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<body>
<div>*** START OF THE PROJECT GUTENBERG EBOOK 52848 ***</div>
<div id="cover" class="img">
<img id="coverpage" src="images/cover.jpg" alt="Sky Nomads—Meteorites in Sky, Field, & Laboratory" width="500" height="724" />
</div>
<div class="img">
<img id="insidecov" src="images/icover.jpg" alt="Sky Nomads—Meteorites in Sky, Field, & Laboratory" width="500" height="723" />
</div>
<div class="box">
<p class="jr1">LINCOLN LAPAZ
<br />AND JEAN LAPAZ</p>
<h1><span class="large">SPACE
<br />NOMADS</span>
<br /><span class="smaller">METEORITES IN SKY,
<br />FIELD, & LABORATORY</span></h1>
<p class="tbcenter">HOLIDAY HOUSE, NEW YORK</p>
</div>
<p class="jr1"><span class="smaller"><span class="sc">COPYRIGHT, 1961, BY LINCOLN LaPAZ & JEAN LaPAZ</span>
<br />PRINTED IN THE U.S.A.</span></p>
<div class="pb" id="Page_2">2</div>
<div class="img" id="fig1">
<img src="images/p02.jpg" alt="" width="800" height="948" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Fireball speeding across field of camera during the photographing
of the Great Spiral Nebula in Andromeda, by Josef Klepesta, at the
Prague Observatory, Czechoslovakia, September 12, 1923.</p>
</div>
<div class="pb" id="Page_5">5</div>
<h2 id="c1"><span class="small">PREFACE</span></h2>
<p>Meteoritics is the study of the only tangible entities that reach
us from outer space. Except for the meteorites, scientists have to depend
entirely on studies of some form of <i>radiation</i> for all their knowledge
of the wider cosmos lying outside of the atmosphere of the earth.
And none of the radiations reaching us from various sources afar can
be held in the hand for examination. Each type of radiant energy incident
upon our earth—whether that energy be light from the sun or
from the more distant stars or the galaxies, or the reflected light from
the planets and moons of our Solar System, or the less familiar forms
of radiation, such as radio waves and cosmic rays—must be measured
and permanently recorded by complicated instruments. Often the results
given by even the most sensitive and tractable of these scientific
robots turn out to be exceedingly difficult for man, their master, to
interpret.</p>
<p>But the meteorites require no such temperamental instruments for
their measurement. They are themselves a permanent record. They
can be weighed, sectioned, and polished. They can be studied chemically,
microscopically, and radiometrically. In fact, they can be investigated
<i>directly</i>, just as they are themselves, in our hands, by any
method modern science may be clever enough to devise.</p>
<p>This is why, now with the world’s attention drawn to ambitious
plans for the exploration of the cosmos, meteors and meteorites are
of increasing interest and importance.</p>
<p>We have planned and written this book to be a sound and yet
largely nontechnical introduction to the science of meteoritics. Our
daily experiences in the Institute of Meteoritics have afforded us a
<span class="pb" id="Page_6">6</span>
fortunate advantage in making such a presentation. For, in addition
to our work in the field, laboratory, and classrooms, we have
frequently conducted young people through the museum and workrooms
of the Institute and so have had the opportunity of learning
their point of view at the same time they were venturing into ours. We
hope our book will instill in the reader an abiding interest in the location
and protection, the recovery and preservation and especially in
the study of those cosmic missiles of iron, iron-stone, or stony composition
that represent mankind’s only ponderable links with the vast
universe lying beyond the limits of the earth’s atmosphere.</p>
<p>Although all photographs and special depictions not made by our
staff are individually credited, we wish to express our personal thanks
for the privilege of reprinting them here. All photographs that are
without a credit line have been made by members of our staff.</p>
<p><span class="lr"><i>Lincoln LaPaz</i><span class="hst"> <i>Jean LaPaz</i></span></span>
<span class="lr"><i>University of New Mexico, Albuquerque, March 20, 1961</i></span></p>
<div class="pb" id="Page_7">7</div>
<h2 class="center">TABLE OF CONTENTS</h2>
<dl class="toc">
<dt><a href="#c1"><span class="cn"> </span>PREFACE</a> 5</dt>
<dt><a href="#c2"><span class="cn">1. </span>A METEORITE FALLS IN THE TAIGA, U.S.S.R.</a> 11</dt>
<dt><a href="#c3"><span class="cn">2. </span>A METEORITE FALLS IN THE WHEATLAND, U.S.A.</a> 23</dt>
<dt><a href="#c4"><span class="cn">3. </span>FOUND AND LOST GIANTS</a> 36</dt>
<dt><a href="#c5"><span class="cn">4. </span>WHEN IS A CRATER A METEORITE CRATER?</a> 42</dt>
<dt><a href="#c6"><span class="cn">5. </span>HEAVEN KNOWS WHERE OR WHEN</a> 66</dt>
<dt><a href="#c7"><span class="cn">6. </span>FINDERS FOOLISH, FINDERS WISE</a> 75</dt>
<dt><a href="#c8"><span class="cn">7. </span>LANDMARKS, SKYMARKS, & DETECTORS</a> 84</dt>
<dt><a href="#c9"><span class="cn">8. </span>THE NATURE OF METEORS</a> 101</dt>
<dt><a href="#c10"><span class="cn">9. </span>THE NATURE OF METEORITES</a> 118</dt>
<dt><a href="#c11"><span class="cn">10. </span>TEKTITES, IMPACTITES, & “FOSSIL” METEORITES</a> 134</dt>
<dt><a href="#c12"><span class="cn">11. </span>OMENS AND FANTASIES</a> 147</dt>
<dt><a href="#c13"><span class="cn">12. </span>THE MODERN VIEW</a> 158</dt>
<dt><a href="#c14"><span class="cn">13. </span>PRESENT AND FUTURE APPLICATIONS</a> 166</dt>
<dt><a href="#c15"><span class="cn"> </span>FOR FURTHER READING</a> 177</dt>
<dt><a href="#c16"><span class="cn"> </span>INDEX</a> 181</dt>
</dl>
<h1 title="">SPACE NOMADS
<br />METEORITES IN SKY, FIELD, & LABORATORY</h1>
<div class="pb" id="Page_10">10</div>
<div class="img" id="fig2">
<img src="images/p03.jpg" alt="" width="703" height="800" />
<p class="pcap">Painting of the Ussuri fireball by the Iman artist, P. I. Medvedev.</p>
</div>
<div class="pb" id="Page_11">11</div>
<h2 id="c2"><span class="small">1. A METEORITE FALLS IN THE TAIGA, U.S.S.R.</span></h2>
<p>The morning of February 12, 1947, dawned cold but bright
and sunny in the wide Ussuri valley of Eastern Siberia. During
the early morning hours the people in the villages went about
their everyday chores as usual. Farmers fed and watered their
livestock, while housewives tidied rooms and fired up stoves for
heating and baking. Miners went to work deep underground.
An artist seated himself outdoors near his home to make exercise
sketches. In a densely wooded area on the slopes of a
nearby mountain range, a logging crew began a day’s timber-cutting.</p>
<p>Suddenly, at 10:35 a.m., an extraordinarily large and brilliant
fireball flashed above the central part of the mountain
range. It streaked across the sky in less than 5 seconds and
disappeared beyond the western foothills of the range. Then the
inhabitants of a wide area heard what seemed to them a mighty
thunderclap followed by a powerful roar like an artillery cannonade.
Many people felt a strong airwave. (Field parties later
found that those who noticed this effect were quite close to the
place where the meteorite fell.)</p>
<p>For several hours afterward, a large black column of smoke
tinged with a reddish-rose color stood above the place of fall.
Gradually, this cloud spread outward, became curved and then
zigzag in form, and finally vanished toward the end of the day.</p>
<p>The flash of the fireball and the loud noises that followed it
<span class="pb" id="Page_12">12</span>
caused panic among the farm animals. Cows lowed mournfully
and herds of goats scattered in every direction, chickens and
other fowl squawked in alarm, and dogs ran whining for shelter
or crouched against the legs of their masters.</p>
<p>In the villages, the airwave blew snow off the roofs of houses
and other buildings, while the strong earth-shocks opened windows
and made doors swing ajar. Housewives were dismayed
to see glass windowpanes shattered in their frames and burning
coals and firebrands jolted out of the wood-burning stoves.</p>
<p>Even deep in the mineshaft, the vibrations in the air were
strong enough to snuff out the miners’ lamps, leaving the men
in darkness.</p>
<p>On seeing the huge fireball streak across the sky, the artist
put aside his practice sketch and began a picture of the display
before his impressions of it could fade. His painting of this
natural event is now famous. Not only is it on display in scientific
museums all around the world, but a color reproduction
of it has been issued in Russia as a postage stamp.</p>
<p>The forester supervising the logging crew reported that his
attention was first attracted to the sky when he noticed a strange
“second” shadow rotating rapidly about the tree that cast it.
On looking up, he saw a blindingly bright fireball, twice as large
as the sun, a fiery globe that threw off multicolored sparks as
it passed. Not long after the fireball disappeared behind the
trees, the forester heard a loud noise like nearby cannonading
and saw a large dark-colored cloud—later tinged with red—billow
up over the impact point. (The members of the logging
crew were among the very few persons actually abroad near
<span class="pb" id="Page_13">13</span>
the place of fall. It turned out that they were only about 9 miles
from it.)</p>
<p>As soon as the many eyewitnesses of the fireball had recovered
from their fright, the questions almost everyone asked
were “What could it have been?” and “Where did it come
down?” To answer the first question was not as difficult as to
answer the second. Local scientists in Vladivostok and Khabarovsk,
the nearest cities of some size, suspected from the first
that a very large meteorite fall had occurred. But exactly where?
All they could be certain of was that the impact point lay in
the Ussuri taiga, a formidable wilderness.</p>
<p>The Sikhote-Alin mountains lie along the Siberian coast between
the Sea of Japan and the Tatar Strait. The Ussuri taiga
is a vast, low-lying, marshy, densely forested region fronting
the western flanks of these mountains. Ordinary cedars, pines,
oaks, and aspen grow in the taiga, but the region is also noted
for such rare plants and trees as the celebrated ginseng, the
cork tree, the Greek nut tree, and the black birch. Wild grape
and ivy vines intertwine the upper branches of the thick forest,
and the trunks of the trees themselves rise from an almost impenetrable
maze of brush and downed timber.</p>
<p>So dense is the forest that in summer, a man can see no more
than 10 or 12 feet in any direction. Yet in winter, the explorer’s
lot is no easier; for, although the deciduous trees then stand
leafless, the ground is covered by three feet or more of snow.
And in the early fall, violent cloudbursts often flood the taiga,
making travel impossible.</p>
<p>Such was the inhospitable region in which the Ussuri, or (as
<span class="pb" id="Page_14">14</span>
it is now known in the U.S.S.R.) Sikhote-Alin meteorite, had
chanced to fall. For any search parties traveling on the ground,
the likelihood that they could find the fallen meteorite in that
wilderness would have been very small.</p>
<p>The impact point of the Ussuri meteorite was discovered in
the only way really practical: from the air. Fortunately, the
center of impact lay almost directly below the airlane connecting
the towns of Iman and Ulunga, so that the devastation produced
by the meteorite fall in the taiga was clearly visible to
aviators following this active air route.</p>
<p>The accounts several fliers gave concerning the widespread
cratering and destruction they had seen from the air in the impact
area led to the organization of two separate ground-search
parties, one at Khabarovsk, the other at Vladivostok. The Khabarovsk
group, made up of four members of the Geological
Society, flew to the village of Kharkovo, the inhabited point
nearest the site of fall. After a rough and dangerous landing
on the small, snow-covered airfield at Kharkovo, the geologists
began their trek into the taiga on foot. Throughout the entire
trip, the men, burdened with supplies and equipment, waded
through waist-deep snow and camped in the open despite the
arctic cold.</p>
<p>At almost the same time, a geologist from Vladivostok set
out from the railway line up the Ussuri valley to track down
the fallen meteorite. His progress was even more difficult than
that of the Khabarovsk party. In addition to following a much
longer route, he did not have the invaluable information that
the first party had got from the aviators. He had to make his
way slowly from village to village, questioning eyewitnesses as
he went and gradually determining the probable end-point of
the meteorite fall.</p>
<div class="pb" id="Page_15">15</div>
<div class="img" id="fig3">
<img src="images/p04.jpg" alt="" width="800" height="598" />
<p class="pcap"><span class="jr">COURTESY OF E. L. KRINOV</span>
Splintered and broken trees at the site of the Ussuri fall.</p>
</div>
<div class="pb" id="Page_16">16</div>
<p>The route followed by the Vladivostok geologist lay through
the heart of the trackless snow-covered taiga. Fortunately, he
had with him two hunters who were well acquainted with the
rigors of travel through the taiga and knew how to live off the
land.</p>
<p>They slept in hunters’ huts or under overhanging trees, drank
melted snow water, and ate fried quail. But they had not gone
far when they found that their footwear was completely useless
for a trek through the wet, snowy taiga, because their felt hiking
boots quickly soaked up water and became very heavy. So they
swathed their feet in warm dry grass over which they tied large
pieces of untanned leather. After that, the walking was much
easier. They were able to cover the ground so rapidly that they
reached Kharkovo only a day after the Khabarovsk geologists
had landed there at the small airfield.</p>
<p>At Kharkovo, the three feasted on pork, milk, and honey.
Then loading a few provisions on a borrowed horse, they started
out to overtake the Khabarovsk party. They made such good
time that the two groups were able to join forces and to enter
the impact area as one expedition, on February 24, 1947.</p>
<p>A scene of great desolation awaited them in the central region
of the meteorite fall. Masses of crushed stone had been
hurled hundreds of feet by the violent impact. Denuded, uprooted
trees lay about—some cut in two as neatly as if by a
saw. Large cedars had been splintered where they stood or had
been torn up by the roots and thrown some scores of yards.</p>
<div class="pb" id="Page_17">17</div>
<div class="img" id="fig4">
<img src="images/p05.jpg" alt="" width="800" height="598" />
<p class="pcap"><span class="jr">COURTESY OF E. L. KRINOV</span>
Workmen excavating one of the large craters formed by the impact
of the Ussuri meteorites.</p>
</div>
<div class="pb" id="Page_18">18</div>
<p>Most impressive of all, though, were the numerous meteorite
craters ranging in size from small bowl-like features to a basin
more than 28 yards across and over 6 yards deep—a depression
large enough to hold a two-story house. The investigators recovered
many fragments of the iron meteorite that had broken
to pieces not far above the earth’s surface and had peppered the
area of fall with high-speed meteoritic “shrapnel.”</p>
<p>With their meteorite recoveries and photographs of the cratered
area, the members of this first expedition returned to their
respective towns and began a campaign by letter and wire to
interest the Moscow office of the Academy of Sciences of the
U.S.S.R. in making a full-scale investigation of the Ussuri fall.
The officials of the Academy decided at once to send a special
scientific expedition to the site of the meteorite fall.</p>
<p>A member of this later and better-equipped expedition compared
the Ussuri crater field to a bombed-out area. In fact, some
of the meteorite specimens were fragments that closely resembled
pieces of shattered shell-casing. The edges of these fragments
were jagged and bent, and their surfaces, which often displayed
a rainbow-colored sheen, were grooved and scarred by
impact against the hard rock underlying the region in which the
crater field had been formed. In rare instances, the investigators
noted spiral twisting of the fragments, an indication of the unusually
violent disruptive forces to which they had been subjected
at impact.</p>
<p>The scientists found several instances in which fist-sized
meteorite fragments had actually penetrated into or through
standing tree trunks, either becoming imbedded in the wood or
driving a hole right through the trunk.</p>
<div class="pb" id="Page_19">19</div>
<div class="img" id="fig5">
<img src="images/p06.jpg" alt="" width="800" height="623" />
<p class="pcap"><span class="jr">COURTESY OF E. L. KRINOV</span>
A nickel-iron meteorite from the Ussuri fall imbedded in the trunk
of a cedar tree.</p>
</div>
<div class="pb" id="Page_20">20</div>
<p>Many whole individual meteorites also were recovered.
These were almost always covered by a thin, smooth “glaze”
known as <i>fusion crust</i>. This crust forms on the surface of a
meteorite as it plunges rapidly through the air. The heat generated
during its flight causes the outer “skin” of the meteorite to
melt. Later, when the mass has cooled off, the thin coating of
melted material hardens, forming a rind or crust.</p>
<p>By the beginning of 1951, the Russians had sent three more
expeditions to the site of the Ussuri fall. Their scientists found,
in all, 122 craters (the largest more than 80 feet in diameter) as
well as numerous funnels resulting from the penetration of
smaller meteorites into the earth. By means of both visual and
instrumental searches, they also recovered 20,000 meteoritic
fragments and individual meteorites. The smallest Ussuri specimens
weighed no more than the thousandth part of a gram.
(There are 453.59 grams in a pound.) Some of these tiny masses
were found lying cupped in leaves. The largest individual meteorite
recovered weighed about 3,839 pounds. Altogether, approximately
23 tons of meteoritic material from the Ussuri fall
are now in the collection of the Meteorite Committee of the
Academy of Sciences, Moscow, while another 47 tons are believed
to still be buried in the Ussuri crater field.</p>
<div class="pb" id="Page_21">21</div>
<div class="img" id="fig6">
<img src="images/p07.jpg" alt="" width="800" height="521" />
<p class="pcap"><span class="jr">COURTESY OF E. L. KRINOV</span>
An individual Ussuri meteorite with fusion crust and characteristic
surface sculpturing produced during high-speed flight through the
resisting atmosphere.</p>
</div>
<div class="pb" id="Page_22">22</div>
<p>The Russian scientists carefully mapped the locations of the
individual craters, penetration funnels, and meteorite recoveries.
They made geologic and magnetometric surveys of the
crater field, took aerial photographs of the entire area of fall,
and prepared a documentary motion-picture covering the activities
of the various expeditions. The area of the crater field
has been set aside by the Russian government as a sort of scientific
preserve, and is being made into the equivalent of what is
termed a National Monument in the U.S.A. Several of the
typical craters are protected by overroofed shelters to preserve
these features for generations yet to come.</p>
<div class="pb" id="Page_23">23</div>
<h2 id="c3"><span class="small">2. A METEORITE FALLS IN THE WHEATLAND, U.S.A.</span></h2>
<p>February 18, 1948, had been a pleasant day in northwestern
Kansas and as the supper hour approached, the sky remained
blue and cloudless. Shortly before 5:00 p.m., a few people were
still out of doors. An eleven-year old girl was hanging up the
last of the family wash on a high clothesline. In the late afternoon
sunshine, a woman and her son were enjoying a walk
around the back yard of their home on a large Kansas ranch.
Outside his house, a ten-year old boy was playing basketball
with friends. A veteran of World War II was loading fodder in
a silo. In the feedlot of his ranch, a farmer was stacking hay.
A filling station attendant was working outside at the pumps,
grateful for a spell of milder winter weather.</p>
<p>Without warning, a large and very bright fireball streaked
across the clear sky from southwest to northeast. Ominous-looking
white smoke-clouds mushroomed up from points in the
fireball’s path. Shortly after the fireball disappeared, loud explosions
and rumbling sounds drove thousands of people out
into the open. The whole astonishing luminous display was over
in a few seconds, but the strange clouds and the frightening
sounds that followed the fireball’s passage continued much
longer.</p>
<p>Although startled by the brilliant fireball and the strange
thundering noises, the young girl, whose face had been turned
skyward as she hung up the clothes, noted very carefully where
<span class="pb" id="Page_24">24</span>
she had seen the fireball disappear behind the tallest building
in her home town. (Her sighting was later of great value to field
parties from the Institute of Meteoritics of the University of
New Mexico.)</p>
<p>The woman and her son were amazed to see an angry, boiling
white cloud tinged with red developing overhead in the
blue sky and to hear strange whizzing noises in the air around
them.</p>
<p>The boy playing basketball heard a peculiar whistling or
hissing noise just as he was ready to shoot a basket and, on
looking up, saw the ball of fire slanting earthward. (This boy’s
report was of particular interest, since it related to an unusual
type of “sound” that travels at the speed of light rather than
at the velocity of ordinary soundwaves.)</p>
<p>As a cannonading louder than any the veteran had heard on
the battlefields of Europe echoed over the rolling countryside,
he went temporarily into a state of shock.</p>
<p>The farmer stacking hay heard several explosions, felt a violent
air blast, and finally heard a solid object strike the ground
“with a smack,” as he put it, “like a clod hitting the earth.”
(Later, field searchers found that this man lived only about two
and a half miles south of the point where the largest fragment of
the meteorite fell.)</p>
<p>Shortly after the passage of the fireball, the filling station
attendant felt the legs of his trousers flap as if he were standing
in a high wind, although he was more than 11 miles distant from
the actual path along which the fireball moved on its way to the
earth.</p>
<div class="pb" id="Page_25">25</div>
<p>As in the case of the Ussuri fall, which had occurred about a
year earlier, farm animals, chickens, and dogs were terrified by
the strange and noisy event. Cattle tried to run through a fence
to escape the deafening racket. A fine pair of horses panicked
and ran headlong into a narrow gully, the walls of which collapsed
on them during their struggles. Chickens dashed for the
henhouse, screeching and cackling all the way. A dog that feared
lightning jumped behind a haystack and finally ran to his master
in alarm.</p>
<p>Although the majority of the people did not see the fireball
itself, they were driven out-of-doors by the violent concussions
that followed its passage, and thus got out under the open sky
in ample time to see several large, turbulent white clouds mushrooming
far overhead. From these clouds, a thick powder or
dust filtered down through the air and collected on the surfaces
of stock ponds and water tanks.</p>
<p>Some people thought the peculiar clouds were similar to
those produced by atom bomb explosions. Many suspected that
a V-2 rocket had “run away” from the proving ground at White
Sands, New Mexico. One man disagreed with the opinion of
his friends that the military had been experimenting and declared
that it was “the Lord who was experimenting!”</p>
<p>The February 18 meteorite fall caused great excitement
throughout Kansas and Nebraska, and it was the chief topic of
conversation for days among the residents of the many small
farming communities along the western half of the Kansas-Nebraska
state line.</p>
<p>The Ussuri fall was studied by Russian scientists exclusively,
<span class="pb" id="Page_26">26</span>
and we have of necessity given, in Chapter 1, a secondhand
account of the fall and surveys the Russians made; but
field parties from the Institute of Meteoritics conducted on-the-spot
investigations of the Norton, Kansas fall. As we were members
of several of these field parties, the story to follow is a
firsthand report.</p>
<p>A little before 6:00 p.m. on February 18, word of the mysterious
explosion centering near Norton, Kansas reached the
Institute of Meteoritics, in Albuquerque, N. M., through the
kind offices of Civil Air Patrol personnel. Since a number of
early reports had described the incident as an airplane falling
in flames, it was only natural that the Civil Air Patrol and similar
groups would take an interest in the occurrence. At once,
the staff of the Institute began to interview eyewitnesses of the
event through Civil Air Patrol channels and by long distance
telephone, telegram, and letter. Soon we had collected enough
information to show clearly that a large meteorite fall had been
responsible for the unusual light and sound effects that had
startled the inhabitants of Kansas, Nebraska, and adjoining
states.</p>
<p>By March 3, the Institute staff had made a first determination
of the probable area of fall. The center of this oval-shaped, 8
by 4 mile area lay about 15 miles north-northwest of Norton,
Kansas and nearly on the Kansas-Nebraska state line. The
meteorite had fallen in a region of wheat fields, pasture lands,
and widely scattered farm houses. The countryside there is open
and gently rolling. The small creeks winding through shallow
valleys are marked in spring and summer by narrow bands of
low green trees and bushes. Many of the hillsides are covered
with unplowed buffalo sod.</p>
<div class="pb" id="Page_27">27</div>
<div class="img" id="fig7">
<img src="images/p08.jpg" alt="" width="800" height="573" />
<p class="pcap">A fragment of the Norton fall is removed still imbedded in the tough
buffalo grass sod into which it penetrated.</p>
</div>
<div class="pb" id="Page_28">28</div>
<p>On March 24, a field party left the University of New Mexico
to make a survey of this area. Unfortunately, Kansas blizzards
can be as severe as any in Siberia, and although the scientists
gathered many helpful reports from eyewitnesses of the fall,
heavy snow and high winds seriously hampered the work. The
information they collected, however, confirmed the accuracy
of the Institute staff’s first determination of the probable area
of fall.</p>
<p>Late in the spring, a farmer in this area found a “strange
stone” on his land and held it for identification by the second
Institute party. This strange stone—which smelled like sulfur
and had metallic specks in it—was the first piece of the fallen
meteorite to be recovered.</p>
<p>Scientists and farmers soon found many other fragments during
systematic searches of the rolling farm and pasture lands.
The fourteen-year-old boy who had been walking with his
mother at the time of the fall discovered a 130-pound fragment
of the meteorite in a pasture that had already been carefully
searched by grown-up meteorite hunters! This find was one of
the two largest fragments recovered from the entire fall. The
landing place of this large piece was marked only by a small
hole in the sod, but, on prodding into this hole, the boy struck
something rather solid. He ran at once to tell the lady who
owned the pastureland, and together they dug out the fine
meteorite.</p>
<div class="pb" id="Page_29">29</div>
<div class="img" id="fig8">
<img src="images/p09.jpg" alt="" width="800" height="660" />
<p class="pcap">The Furnas County, Nebraska, stony meteorite in place at the bottom
of its 10-foot “penetration funnel.”</p>
</div>
<div class="pb" id="Page_30">30</div>
<p>This discovery brought interest in finding meteorites to a
fever pitch, and it was soon possible to look in almost any direction
and see farmers, or their wives and children, walking slowly
across the fields and looking for meteorites.</p>
<p>Finally, in August, two farmers cutting wheat in a field just
a short distance north of the Kansas-Nebraska state line found
a deep hole when their tractor almost fell into it. They investigated
and discovered that a very large fragment of the meteorite
had buried itself deep in the ground.</p>
<p>Scientists from the University of Nebraska and the Institute
of Meteoritics carefully excavated this huge meteorite. They
found that the mass had plunged more than 10 feet into the
earth. Quite by chance, its lower surface had come to rest in
the ashes of a long-buried primitive cooking site.</p>
<p>The excavated meteorite looked and felt like a huge stone.
Actually, it was stony in nature, but of a texture so fragile that
it had to be wrapped in tissue paper, then in burlap, and finally
covered with a thick coating of plaster of Paris before it could
be lifted out of the ground. Those in charge of the removal of
the meteorite borrowed this procedure from the paleontologists,
who use it in the removal of fossil tusks and bones that otherwise
would crumble away.</p>
<p>After the great meteorite had been raised out of the excavation,
it was taken by truck to the University of New Mexico, in
Albuquerque. There it was put on display beside the smaller
130-pound fragment found in May. By careful measurements,
scientists determined the weight of the main mass to be approximately
2,360 pounds—a record weight for stony meteorites.<a class="fn" id="fr_1" href="#fn_1">[1]</a>
This remarkable meteorite, known as the Furnas County, Nebraska,
stone, is now a prized item in the collection of the Institute
of Meteoritics.</p>
<div class="pb" id="Page_31">31</div>
<div class="img" id="fig9">
<img src="images/p10.jpg" alt="" width="800" height="658" />
<p class="pcap">Field party proudly surrounds the Furnas stone in its protective
“armor.”</p>
</div>
<div class="pb" id="Page_32">32</div>
<p>As more and more finds were made in the area of fall, we
accurately recorded their weights and mapped their locations.
In this way, we could tell how the pieces of the meteorite had
distributed themselves according to size and weight over the
oval-shaped area. The smaller and lighter fragments were
slowed down by air resistance and fell first, while the 2,360-pound
mass carried on beyond them and came to earth at the
farthest point along the direction of flight.</p>
<p>The staff of the Institute took many photographs of the meteorites
that were found, of the impact funnel made by the largest
mass, and of the excavation and removal of that giant stone.
Some of these pictures were published in scientific journals,
others in magazine and newspaper articles. A few of our best
photographs are included in this chapter.</p>
<p>Although the light and sound effects that accompanied the
Ussuri and Norton falls were similar, the meteorites recovered
from them were not at all alike. The Ussuri specimens were
masses of nickel-iron so malleable that on high-speed impact
with hard rock they had held together and taken twisted and
ragged shapes. But the Norton meteorites were very fragile
stony masses, many of which went to pieces either in the air or
when they struck the ground. Almost all of the recoveries made
of this very rare type of stony meteorite were fragments, not
whole specimens. They somewhat resembled pieces of a strange
whitish mixture of chalk and crystalline limestone containing
tiny specks and lumps of nickel-iron. Many specimens were
covered wholly or in part by a shiny varnish-like fusion crust,
varying in color from jet black through yellow to almost pure
white.</p>
<div class="pb" id="Page_33">33</div>
<div class="img" id="fig10">
<img src="images/p11.jpg" alt="" width="800" height="564" />
<p class="pcap">The Furnas stone, protected by its “armor,” hangs suspended from
the truck crane that raised it out of its deep “penetration funnel” in
the earth.</p>
</div>
<div class="pb" id="Page_34">34</div>
<p>The largest meteorite recovered from the Norton fall was
the 2,360-pound mass that formed the deep impact funnel. The
smallest Norton specimens, like their Ussuri counterparts,
weighed no more than the thousandth part of a gram. Altogether,
nearly a ton and a half of meteoritic material from the
Norton fall was collected by the Institute. Other small fragments
may remain undiscovered in the Kansas and Nebraska
wheatlands, but, unfortunately, because of the soft and fragile
nature of the material they are composed of, it is likely that they
have now weathered away so completely that they are no longer
recognizable as meteorites.</p>
<p>Our stories of the Ussuri and Norton meteorite falls show
how hard scientists work themselves (and others!) to find meteorites.
Therefore meteorites must be important. The two accounts
given also make clear that investigators of meteorite
falls are almost entirely dependent upon observations made by
nonscientists.</p>
<p>Scientists investigating meteorite falls greatly appreciate the
help given them by children and adults alike. Field parties are
powerless without it, and we should like to encourage people
of all ages to continue this type of valuable cooperation. In
Chapter 7, we shall tell more about how the individual observer
of a meteorite fall can make his report really count.</p>
<div class="pb" id="Page_35">35</div>
<div class="img" id="fig11">
<img src="images/p12.jpg" alt="" width="800" height="645" />
<p class="pcap">A close-up of the Furnas County stone, the largest stony meteorite
ever recovered.</p>
</div>
<div class="pb" id="Page_36">36</div>
<h2 id="c4"><span class="small">3. FOUND AND LOST GIANTS</span></h2>
<p>All meteorites are important from the standpoint of
science, but a few deserve special mention because of the human-interest
stories connected with them.</p>
<p>First place among famous finds should no doubt go to the
massive Cape York, Greenland, iron, the largest recovered
meteorite actually to have been weighed. The Eskimos called
this enormous object “Ahnighito,” which means “The Tent.”
Robert E. Peary, the discoverer of the North Pole, brought it to
New York City by ship in 1897. His party had great difficulty
hoisting the 34-ton mass aboard. Later, when the ship had put
to sea, she encountered a serious navigational hazard. To the
amazement and alarm of the crew, the huge nickel-iron meteorite
caused magnetic disturbances that severely affected the
ship’s compass.</p>
<p>Another of the giant meteorites, the 14-ton Willamette, Oregon,
iron, became the center of a long legal battle in the early
1900’s. The man who originally found the meteorite and recognized
its true nature felt that because the iron was on the
surface of the ground and not buried beneath it (as the ore of
a metal would have been), there was no reason why he should
not move the mass from the place of find to his own property,
three-fourths of a mile away. He did this very laboriously by
means of a log-timber car, a capstan with wire rope, and a
small horse. On learning what the finder had done, the company
that owned the land from which the meteorite had been removed
put its attorneys on the job of recovering the “purloined”
meteorite. The Oregon courts, bowing to decisions made in
previous cases involving ownership of meteorites, brought in
a verdict favoring the owners of the land. Although the finder
of the Willamette meteorite lost the decision, he nevertheless
won the distinction of being the only man to have successfully
made off with a treasure weighing 14 tons!</p>
<div class="pb" id="Page_37">37</div>
<div class="img" id="fig12">
<img src="images/p13.jpg" alt="" width="800" height="350" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Peary’s photograph of the Cape York meteorite as it was being
moved for loading aboard his ship.</p>
</div>
<div class="img" id="fig13">
<img src="images/p13a.jpg" alt="" width="800" height="417" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Arrival of the 34-ton iron mass
at the American Museum of Natural History, New York City.</p>
</div>
<div class="pb" id="Page_38">38</div>
<p>The biggest meteorite of all, of course, is the one that “got
away.” In 1916, a captain in the Mauritanian army was taken
by a native guide, secretly and at night, to the site of a colossal
iron meteorite located in the dunes of the Adrar desert, in the
far western reaches of the vast Sahara. The officer described the
mass as measuring 100 meters (over 300 feet) by 40 meters (over
120 feet), with the third dimension hidden by the sand dunes.
According to him, the mass “... jutted up in the midst of sand
dunes that were covered by a desert plant, the <i>sba</i>, and it had
the form of a compact, unfissured parallelopiped. The visible
portion of the surface was vertical, dominating in the manner of
a cliff, the wind-blown sand that was scooped away from the
base of the mass so that the summit overhung; and that portion
exposed to eolian [wind] erosion was polished like a mirror.”</p>
<p>The captain, at the request of his uneasy guide, returned from
his hurried excursion without taking notes or making a map.
But he did bring back a small 10-pound fragment of iron which
he had found lying on top of the giant mass. This small fragment
later proved to be a genuine meteorite, and is the only
known specimen of the famous Adrar mass. It is preserved at
present in the Museum of Natural History at Paris.</p>
<div class="pb" id="Page_39">39</div>
<div class="img" id="fig14">
<img src="images/p14.jpg" alt="" width="800" height="621" />
<p class="pcap"><span class="jr">J. OTIS WHEELOCK PHOTO</span>
<span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Man and boy carrying off the famous “purloined” Willamette meteorite
on a homemade dolly car with wheels of tree-trunk sections.
Note hole piercing this 14-ton chunk of iron.</p>
</div>
<div class="pb" id="Page_40">40</div>
<p>What has been called a conspiracy of silence among the natives
of the Adrar area and the inhospitable nature of the region
itself have successfully preserved the secret of the location of
the enormous metallic mass described by the captain. The native
guide died, apparently of poison, and although many inhabitants
of the region are no doubt familiar with the whereabouts
of the mass (whatever it is!), those questioned have
consistently denied knowledge of its very existence. All recent
attempts, not only by military but even by scientific expeditions,
to relocate the gigantic metallic mass have failed. The whole
Adrar case remains an intriguing puzzle to be unraveled, it is
hoped, by future generations of meteorite hunters.</p>
<p>Another “lost” meteorite is one composed of stone and iron.
The Port Orford, Oregon, stony-iron (as it is now named) was
originally found in 1859 by a U.S. geologist who was engaged
in a survey of what were then the Oregon and Washington
Territories. According to him, the mass was quite irregular in
shape and “4 or 5 feet [of it] projected from the surface of the
mountain,” while it was “about the same number of feet in
width and perhaps 3 or 4 feet in thickness.” He broke off a small
fragment of it (far smaller than the one taken from Adrar) and
packed this specimen away with his collection of rock and mineral
samples. Years later, the geological collection was cataloged
and analyzed in the East. At that time, the fragment collected
in 1859 was found to be a piece of a stony-iron meteorite.
After that, scientists and others made many attempts to rediscover
the main mass of the large Port Orford meteorite, all of
them unsuccessful. Today the sum total of material recovered
from this stony-iron amounts to 25 grams in the U.S. National
<span class="pb" id="Page_41">41</span>
Museum, about 4 grams in the Natural History Museum of
Vienna, and a few tiny specks in the Museum of the Geological
Survey of India.</p>
<p>The Red River, Texas, iron is still another famous meteorite.
It was originally discovered by Pawnee and Hietan Indians, and
a group of them took a party of traders, in 1808, to the site. Two
years later, two rival parties, each led by a man who had been a
member of the 1808 trading expedition, began a search for the
meteorite. The members of one of the two parties were from
Nacogodoches, Texas. They reached the meteorite first but had
left home so hurriedly on their eager hunt that they were not
properly prepared to move so large a mass. They went away
from the site to get horses and a wagon, after they had laboriously
hidden the meteorite under a huge flat stone, to prevent
the other party from finding it. The members of the other party,
hailing from Natchitoches, Louisiana, set out better prepared.
After a lengthy hunt, they finally found the hidden meteorite.
Using tools they had the foresight to bring, they built a truck
wagon and drove away with their prize. Eventually, the Red
River meteorite, weighing 1,635 pounds, became a part of the
collection at Yale University. But two other, smaller, masses of
the same metal, known in the early days to the Pawnees and a
few traders, remain still undiscovered in the Red River area.</p>
<div class="pb" id="Page_42">42</div>
<h2 id="c5"><span class="small">4. WHEN IS A CRATER A METEORITE CRATER?</span></h2>
<p>Not all meteorites form craters at impact, as the larger Ussuri
fragments did. Even the largest mass of the Norton meteorite
merely buried itself in a funnel-like hole only about 10 feet
deep. And the Russian investigators found a number of the
lighter Ussuri fragments at the bottom of small penetration
funnels. Cosmic missiles that are large enough to blast out craters
in the ground are of particular interest to science, however,
not only because of the extraordinarily intense light, sound,
and other effects that accompany their fall, but also because
they produce characteristic and long-lasting basin-like features
in the outer shell of the earth.</p>
<p>Natural processes that change the surface features of the
earth have long been the subjects of field studies by scientists.
Geologists have carefully investigated the major folds formed
in the earth’s crust by mountain-building forces, the clefts and
depressions resulting from earthquake activity and erosion, and
the vast plains leveled off by the scouring action of great ice-sheets.
All of these different natural processes, though, have one
thing in common: their source is the earth-body itself. They take
place either <i>within</i> the earth’s crust as a result of local shifts or
changes in pressure (like earthquakes and volcanic eruptions),
or <i>on</i> the surface of the earth as a result of the action of water
or of changes in temperature (like erosion and glaciation).</p>
<p>On the other hand, meteorite impact craters are not formed
<span class="pb" id="Page_43">43</span>
by earth-processes at all. As we have seen, they result when
large bodies of matter from the regions of space <i>outside</i> the
earth chance to strike the surface of our planet at high speed.
The study of meteorite craters is therefore a special field. It is
also one of quite recent development; not until 1905 was the first
meteorite crater recognized as such.</p>
<p>The first thing to be said on this subject is, of course, that
not all holes in the ground, however large and impressive, were
necessarily formed by the impact of meteorites. Features that
resemble meteorite craters may result from certain ordinary
earth-processes. For example, the rock layers underlying a particular
area may be dissolved away by waters circulating beneath
the surface of the ground. The overlying crust will eventually
collapse into the empty space, and what geologists call a
“sink hole” or a “sink” is formed. Many such sinks surround the
genuine meteorite crater near Odessa, Texas, and at times have
been mistaken for the real thing.</p>
<p>Since there is some possibility of confusion about whether or
not a hole in the ground is a meteorite crater, it is comforting
to know that scientists have come up with a handy set of rules
for reaching a decision on this point. These rules can be stated
in the form of several questions that crater-investigators should
ask themselves:</p>
<blockquote>
<p>Have you found meteorites in or near the crater-like feature?</p>
<p>In its vicinity, have you found pieces of country rock that show
the effects of high temperature and pressure (melting or crushing)?</p>
</blockquote>
<blockquote>
<div class="pb" id="Page_44">44</div>
<p>Did people actually see a meteorite come to earth at the point
where the crater is located and where, to their certain knowledge,
no crater existed before?</p>
</blockquote>
<p>If the answer to all—or even one—of these questions is
yes, then it is quite likely that the crater-like feature is actually
a meteorite crater. Naturally, if the answer to the <i>first</i> question is
yes, the matter is practically settled in favor of the meteoritic
origin of the feature.</p>
<p>If the impact has taken place in horizontally bedded rock
strata—that is, in flat beds of rock lying one on top of another
like the layers in a stack of griddle cakes—a meteorite crater
will have a characteristic <i>rim</i> of upturned or even overturned
rock layers. (None of the ordinary sink holes near the Odessa
crater show such rims.) In addition, pieces of rock shattered
and thrown out by the impact will be found in all directions
around the crater. The amount and size of this fragmented
material will decrease with distance outward from the crater.</p>
<p>A list of the recognized (or genuine) meteorite craters of the
world is given in the table on <a href="#Page_65">page 65</a>. All of these craters except
the two Russian ones were formed many thousands of years
ago, and, in most cases, the earth processes of erosion and
weathering have by now dimmed the sharp outlines of their
rims and silted up their deep interior funnels until only basin-like
bowls remain.</p>
<div class="pb" id="Page_45">45</div>
<div class="img" id="fig15">
<img src="images/p15.jpg" alt="" width="800" height="451" />
<p class="pcap">Cross-section showing the manner in which horizontally bedded
rock strata may be broken and tilted upward by the impact of a
crater-forming meteorite. This schematic diagram is based on excavations
at several meteorite craters.</p>
</div>
<div class="pb" id="Page_46">46</div>
<p>You may have visited the very first crater in the world to be
recognized by scientists as a meteorite crater. This huge basin,
now known as the Canyon Diablo meteorite crater (although
often referred to incorrectly as “Meteor Crater”), lies about 20
miles west of Winslow, Arizona. It is the best known of all the
craters listed in the table because in recent years it has been
developed under private ownership as one of the leading tourist
attractions on U.S. Highway 66.</p>
<p>From the paved road that turns off Highway 66 toward the
crater, the visitor sees the rim as a chain of low, hummocky,
tan-colored hills which contrast sharply with the grayish or
reddish hue of the desert plain.</p>
<p>The outer slopes of the crater rim rise very gently from the
level plain in which the crater was formed, and they are covered
with rock fragments of various sizes thrown out at the time the
meteorite struck the earth. This fragmented material ranges in
size from tiny particles of “rock-flour” as soft as face-powder
to gigantic solid masses like Monument Rock, which is estimated
to weigh 4,000 tons.</p>
<p>Field parties have found 50- to 100-pound fragments of the
limestone layer underlying the Canyon Diablo area at distances
of 1½ to 2 miles from the crater. Sizable rock and meteorite
fragments out to distances of 6 miles from the rim have turned
up, and smaller fragments of both materials at even greater
distances.</p>
<p>On their first visit to the Canyon Diablo crater, people are
always astonished at the steepness of the inner walls of the crater
and at the very great size of its bowl. This crater is more
than 4,000 feet across and 570 feet deep. It is the largest <i>recognized</i>
meteorite crater so far discovered in the world, although
other larger, basin-like features elsewhere on the surface of the
earth have been suspected but not proved to have a similar
origin.</p>
<div class="pb" id="Page_47">47</div>
<div class="img" id="fig16">
<img src="images/p16.jpg" alt="" width="800" height="655" />
<p class="pcap"><span class="jr">COURTESY OF TRANS-WORLD AIRLINES</span>
Aerial view of the Canyon Diablo, Arizona, meteorite crater.</p>
</div>
<div class="pb" id="Page_48">48</div>
<p>When the Canyon Diablo meteorite plunged into the horizontally
bedded rock layers underlying the area of fall, the
force of the explosion following the impact actually bent these
layers upward. All around the inside of the crater, the rock
strata tilt away from the center at steep angles.</p>
<p>Cowboys, ranchers, and scientists have found thousands of
solid nickel-iron meteorite fragments around the crater. The
largest of these weighs 1,406 pounds. The smallest spherules
and grains are almost or quite microscopic in size. (These tiny
granules have been well known to scientists since 1905 in spite
of current fables claiming that they are a recent discovery.) In
the rim and on the plain outside the crater, large and small <i>shale
balls</i>, composed of weathered meteoritic material, were found
in considerable numbers in the early days. Along with many
solid iron meteorites, shale balls have also been found at various
depths in recent times by field parties from the Institute
employing specially designed meteorite detectors.</p>
<p>In the first two decades of the twentieth century, investigators
sank (at great expense!) a number of shafts and drill holes in
the interior and on the south rim of the crater, in unsuccessful
attempts to locate the supposed “main mass” of the Canyon
Diablo meteorite. Most authorities now believe, however, that
the extremely high temperatures, developed at the time the
Canyon Diablo meteorite penetrated into the earth, changed
almost all of the gigantic cosmic missile into vapor.</p>
<div class="pb" id="Page_49">49</div>
<div class="img" id="fig17">
<img src="images/p17.jpg" alt="" width="800" height="643" />
<p class="pcap">View of the interior of the Canyon Diablo crater showing the steep
inner slopes of the huge basin.</p>
</div>
<div class="pb" id="Page_50">50</div>
<p>No better example of an ancient meteorite crater has been
found than this one near Canyon Diablo. The other craters
listed in the table (even the two recently formed ones), while
bearing resemblances to it, also show individual differences
from it.</p>
<p>Some, like Henbury, Campo del Cielo, and Haviland, are
not single craters but rather consist of fields of craters. In these
cases, the earth was struck not by a single large meteoritic body
that held together right down to impact, but either by a “swarm”
of meteorites traveling together through space or by the fragments
of a large meteorite that separated into pieces shortly
before it struck the surface of the ground.</p>
<p>Again, the type of ground into which the meteorite strikes
affects the character of the craters formed. As an illustration,
the Wabar, Arabia, craters were not smashed out of sedimentary,
horizontally bedded rock layers (as was the Canyon Diablo
crater) but were formed in clean desert sand dunes. In this
case, the crater rims are composed primarily of almost pure
silica-glass formed by the fusion of the sand at the time of impact.
It is not hard to imagine the terrific boiling and frothing
up of melted sand and meteoritic material that must have accompanied
the formation of the Wabar craters.</p>
<p>Except for Podkamennaya Tunguska and Ussuri, the craters
listed in the table were formed, as we have mentioned, a great
many thousands of years in the past. Just how many thousands
is a difficult question to answer, for all of our estimates must
necessarily be made on the basis of <i>indirect</i> evidence rather than
on <i>direct</i> observation.</p>
<div class="pb" id="Page_51">51</div>
<div class="img" id="fig18">
<img src="images/p18.jpg" alt="" width="800" height="776" />
<p class="pcap">Before impact of Canyon Diablo meteorite, these rock layers were
horizontal.</p>
</div>
<div class="pb" id="Page_52">52</div>
<p>Paleontologists, geologists, and other scientists give us an
age of from 20,000 to 70,000 years for the Canyon Diablo crater.
The discovery of the fossil remains of a prehistoric horse
buried in the Odessa, Texas, crater fill has shown that the age
of that crater is not less than 200,000 years. The oldest craters
known in the United States are the Haviland group produced by
the Brenham, Kansas, meteorites. Long-continued weathering
has almost completely worn down the rims and covered up the
craters of this group. On the basis of the rate at which nickel-oxide
has spread out into the soil about a large deeply buried
Brenham meteorite, calculations carried out at the Institute
of Meteoritics have led to a tentative age of more than 600,000
years for the Kansas craters.</p>
<p>Perhaps the oldest meteorite crater of all is the one blasted
into what the geologists identify as pre-Cambrian quartzite at
Wolf Creek, Western Australia. Even the highly resistant iron
meteorites found around this crater have almost completely
weathered away. Only tiny specks and thin veinlets of metal
are now visible on the cut surfaces of meteorites that, untold
hundreds of thousands of years ago, were solid masses of nickel-iron.</p>
<p>You may have noticed that the widely publicized circular,
water-filled Chubb crater in the Quebec Province of Canada
was not included in the table. This Canadian feature was left
out because the answer to each of the three questions listed
earlier in this chapter is no.</p>
<div class="pb" id="Page_53">53</div>
<div class="img" id="fig19">
<img src="images/p19.jpg" alt="" width="800" height="596" />
<p class="pcap"><span class="jr">COURTESY OF WILLIAM A. CASSIDY</span>
Two of the deeply weathered meteorites found at Wolf Creek crater
in western Australia.</p>
</div>
<div class="pb" id="Page_54">54</div>
<p>The field parties that have carefully searched the Chubb
crater and its surroundings, even when they used one of the
Institute’s powerful drag magnets, were unable to find any trace
whatever either of meteorites or of such weathered remains of
meteorites as show the true nature of the Wolf Creek crater.
Furthermore, no searcher has discovered any fragments of
ordinary rock showing the effects of the extreme heat and pressure
that accompany large-scale meteoritic impact. Finally, the
meteorite supposed by some to have produced the Chubb crater
was not a recorded witnessed fall, for the crater is of very
ancient origin indeed.</p>
<p>Perhaps further search of the Chubb crater site and especially
of the debris in its deep, water-filled interior will succeed in
bringing to light either specimens of meteorites or of silica-glass
or other products of meteoritic impact. If so, then and only
then will identification of the Canadian crater as a meteorite
crater be justified.</p>
<p>Up to this point, we have talked only of very old meteorite
craters. But two crater-producing meteorite falls have occurred
within this century, both in Siberia. The Ussuri fall was one of
these and the more recent of the two.</p>
<p>The earlier and more unusual fall took place on June 30,
1908, at about 8:00 a.m., approximately 40 miles northwest of
the trading post of Vanovara. A fireball exceeding the sun in
brilliance flashed across the sky and was followed by extremely
violent airwaves and earth-tremors.</p>
<p>The pressure wave in the atmosphere set up by this meteorite
fall was strong enough to damage roofs and doors of houses
near the point of impact, as for example, in the village of Vanovara.
On both rivers and lakes in the area of fall, the pressure
wave in the air piled up high, sharp-fronted water waves that resembled
<span class="pb" id="Page_55">55</span>
the bores on the Seine and Severn and that upset fishing
craft and swamped other small boats. Throughout a wide region
at somewhat greater distances from the impact point, tidal-like
bores were raised on rivers and lakes. So gigantic was the atmospheric
disturbance, that it was detected at almost every station
in the world where sufficiently sensitive barometers were
in operation.</p>
<p>Eyewitnesses of this meteorite fall said that at the time the
fireball passed near them, they felt almost unbearable heat.</p>
<p>A huge “fiery pillar” rose above the point of impact, which
by good fortune was in a desolate and almost uninhabited
swampy basin between the Chunya and the Podkamennaya
(i.e., “Stony”) Tunguska rivers. The meteorite fall takes its
name from the latter stream.</p>
<p>The central portion of the region of impact is marked not
only by a number of craters in the swampy terrain, but also by
mute evidence of the extraordinary destructive power of the
Podkamennaya Tunguska meteorite. Over an area of many
square miles, the explosion blew down the standing forest so
that the tops of the overthrown trees (estimated by the Russians
to number more than 80,000,000!) all point away from the impact
center. The intense heat charred the trunks and branches
of the trees in this area in much the same way as the heat from
the first of all atomic bomb explosions scorched the desert
shrubs around the test site in south-central New Mexico.</p>
<p>Within the area of fall, countless reindeer belonging to the
native Tunguse herdsmen were killed, only their charred carcasses
remaining. How great the heat released at impact was
<span class="pb" id="Page_56">56</span>
may be judged by the well-established fact that the prized silver
samovars of the nomads were found melted amid the debris of
their flattened camps. In at least one instance, a Tunguse was so
overcome by the terrible event he had witnessed that he was
“sick for a long time.” The whole impact-region came to be
considered as accursed by the natives, who abandoned the use
of all trails crossing it.</p>
<p>For many years the Podkamennaya Tunguska fall was neglected,
partly because of the remoteness of the area in which
it occurred, partly because of unsettled conditions in Russia;
but chiefly because, in general, the Russian scientific and governmental
officials simply did not believe the “fantastic” tales
concerning the fall told by the native Tunguses, from which we
have given a few details above.</p>
<p>Belated study established, however, both the truthfulness of
the Tunguse reports and the exceedingly unusual character of
the meteorite fall itself. In spite of the overwhelming and, in
fact, worldwide evidence that the Podkamennaya Tunguska
fall was one of the greatest and most violent in history, no meteorites
have ever been recovered from any part of the region
devastated by its impact. It is the one and only true meteorite
crater that is meteoriteless!</p>
<p>This strange circumstance led the senior author to suggest,
in 1941, that the almost incredible Podkamennaya Tunguska
incident had resulted from the infall of a meteorite that, together
with an equivalent mass of the earth-target, was transformed
into energy upon contact with our planet. How can such
extraordinary behavior be accounted for?</p>
<div class="pb" id="Page_57">57</div>
<div class="img" id="fig20">
<img src="images/p20.jpg" alt="" width="800" height="817" />
<p class="pcap"><span class="jr">LEONID A. KULIK PHOTO. SOVFOTO</span>
Infall of meteorite, June 30, 1908, had this effect on a Siberian forest.
See <a href="#Page_55">p. 55</a>.</p>
</div>
<div class="pb" id="Page_58">58</div>
<p>The most obvious explanation involves a new and wider
concept of matter. Ordinary terrestrial matter is regarded as
composed of atoms having positively charged nuclei around
which negatively charged electrons revolve.</p>
<p>Suppose that the situation shown in the <a href="#fig21">first diagram</a> were
reversed so that the nucleus of the atom were negatively charged
and the charges of the particles revolving about it were positive,
as in the <a href="#fig21">second diagram</a>. Matter built up from atoms like those
in this diagram would bear somewhat the same relation to ordinary
matter that -2 does to +2. Such matter is now known
variously as <i>reversed matter</i>, <i>anti</i>-matter, or, as it was first called
by V. Rojansky, <i>contraterrene</i> matter. In recent years, scientists
at the University of California Radiation Laboratory have produced
experimentally all the fundamental particles necessary
for the creation of contraterrene matter.</p>
<p>What would happen now if a contraterrene meteorite penetrated
into the ordinary matter of the earth? The answer is that
just as an electron and a positron mutually annihilate each other
when they collide, so the meteorite and an equal mass of the
earth-target itself would vanish at the instant of impact. The
nearest simple analogy to the actual complex physical situation
is represented by the familiar equation -2 + 2 = 0.</p>
<p>Unlike “summing to zero” in simple arithmetic, however, the
disappearance of mass, technically called its annihilation, results
in a release of energy, as was long ago observed in the case
of electron-positron annihilation. Where considerable masses
are annihilated, as in an A-bomb explosion, the amount of energy
released is tremendous, as is now well known to everyone.</p>
<div class="pb" id="Page_59">59</div>
<div class="img" id="fig21">
<img src="images/p21.jpg" alt="" width="800" height="301" />
<p class="pcap"><b>A.</b> Representation of the structure of an atom of ordinary terrestrial
matter. The nucleus is positively charged and around it circle
negatively charged electrons.</p>
<p class="pcap"><b>B.</b> Representation of the structure of an atom of contraterrene matter.
This is the reverse of the situation in (<b>A</b>). The nucleus here is
negatively charged, and around it revolve positively charged electrons,
also called positrons.</p>
</div>
<p>The effect of such an energy release as would accompany the
infall of a contraterrene meteorite would be a <i>natural</i> nuclear
explosion of vast power. Such an explosion would account for
all the sensational phenomena observed at the time of the Podkamennaya
Tunguska incident; and, furthermore, would explain
why the Russian investigators have never succeeded in
recovering meteorites from this fall. (Further details, <a href="#Page_102">p. 102</a>.)</p>
<div class="pb" id="Page_60">60</div>
<p>If the Podkamennaya Tunguska meteorite was contraterrene,
then the soil in the impact area must have been made radioactive
in the same way that the earth around the “ground zero” of
a nuclear explosion is contaminated by radioactivity. After the
senior author had repeatedly urged Russian scientists (who are
the only ones that have been permitted to visit the site of the
Podkamennaya Tunguska fall) to try to detect any long-lasting
radioactivities that might still be present in the ground at Podkamennaya
Tunguska, such a radioactivity survey was finally
carried out in the summer of 1960. According to an official report
of the Soviet news agency TASS, the investigators obtained
“abnormally high radioactivity readings” which the Russians
tentatively considered to be the result of “a natural nuclear explosion”
occurring in the Podkamennaya Tunguska area on
June 30, 1908.</p>
<p>Science-fiction fans in the U.S.S.R. would like to believe that
this “nuclear explosion” resulted from the impact of a Martian
spaceship rather than a contraterrene meteorite. Reputable Russian
scientists, however, have shown how completely absurd
this “fable” of a Martian landing really is.</p>
<p>When and where will the next crater-producing fall occur?
Perhaps on the earth, perhaps on the moon, for our nearest
neighbor in space has also been the target of meteorites of huge
size. The effects of this meteoritic bombardment are shown by
the rarest and most striking type of lunar crater: that which exhibits
long, bright rays extending outward from the crater itself
as the spokes of a wheel radiate from its hub. These so-called
<i>ray-craters</i> show to best advantage at or near the time of full
moon, when they become one of the most remarkable features
visible on our satellite.</p>
<div class="pb" id="Page_61">61</div>
<div class="img" id="fig22">
<img src="images/p22.jpg" alt="" width="800" height="840" />
<p class="pcap"><span class="jr">G. W. RICHEY PHOTO. COURTESY OF YERKES OBSERVATORY</span>
The lunar ray-crater Tycho.</p>
</div>
<div class="pb" id="Page_62">62</div>
<p>In earlier days, most scientists believed that the craters on the
moon had <i>all</i> been formed by volcanic action. Now the pendulum
of scientific opinion seems to have swung toward the view
that <i>all</i> the thousands of lunar craters are the result of meteorite
impacts that took place in the long distant past. Both views are
better examples of how scientific “fashions” control men’s minds
than they are of explanations that really account for all of the
observed facts—as any acceptable explanation must do.</p>
<p>Those who have studied the moon most carefully from an
uncomfortable seat in a cold observatory rather than from a
warm, comfortable armchair are well aware that instead of just
one type of lunar crater, there are really <i>two</i> quite distinct types.
No single “explanation” can be expected to explain satisfactorily
lunar features as strikingly different as:</p>
<p>First, the rare and distinctive <i>ray-craters</i> described above,
which are scattered at random over the moon, just as the points
of impact of meteorites are upon our own globe. (Roughly defined,
a random distribution is one showing no apparent pattern.
For example, if you were to throw a handful of rice up in the
air, the points where the grains of rice finally came to rest on the
floor would be randomly distributed or very nearly so.)</p>
<p>Second, the ordinary or “run-of-the-mill” craters sprinkled
in profuse but non-random fashion over the visible face of our
satellite.</p>
<p>The ray-craters on the moon are the counterparts of the meteorite
craters on the earth. This fact is shown not only by their
<span class="pb" id="Page_63">63</span>
random distribution, but by the long, bright rays which gave
them their name. On the earth, rays of similar appearance, composed
of thrown-out material, are one of the most characteristic
features of explosion craters, whether the cause of the explosion
is the high-speed impact of a great meteorite or the detonation
of a charge of high explosive (either conventional or
nuclear).</p>
<p>The hypothesis that meteorite craters do exist on the moon is
therefore justified even though it applies to far fewer craters
than its supporters believe.</p>
<p>As for the ordinary, non-ray lunar craters, these features are
not at all volcanic craters in the usual sense. One of the few good
things to come out of World War II was the first satisfactory explanation
of the “run-of-the-mill” craters on the moon. Jeremi
Wasiutynski, a brilliant Polish scientist forced to take refuge in
Norway, sought to explain these craters as originating in <i>convection</i>
processes.</p>
<p>While the term “convection” may not be familiar, the role
convection plays in filling the sky with beautiful clouds on a
hot summer’s day is well known. Such cloud formation results
from convection in the gaseous free atmosphere. Much more
remarkable and regular are the results of <i>controlled</i> convection
in layers of <i>liquids</i> rather than gases. Laboratory investigation
of the effects produced by convection processes in heated liquids
formed the basis for Wasiutynski’s new theory.</p>
<p>According to this theory, convection processes in the only
partially solidified outer shell of the youthful moon could have
given rise to great numbers of surface features having the size,
<span class="pb" id="Page_64">64</span>
shape, and distribution of the common lunar craters. In far more
satisfactory fashion than any other theory so far proposed, the
convection-current hypothesis of Wasiutynski explains the many
and distinctive characteristics of the non-ray craters on the
moon.</p>
<div class="pb" id="Page_65">65</div>
<h3>RECOGNIZED METEORITE CRATERS OF THE WORLD</h3>
<table class="center" summary="">
<tr class="th"><th><span class="small">NAME</span> </th><th class="l"><span class="small">LOCATION</span> </th><th class="c"><span class="small">DATE OF RECOGNITION</span></th></tr>
<tr><td class="l">Canyon Diablo </td><td class="l">Coconino County, Arizona </td><td class="c">1905</td></tr>
<tr><td class="l">Odessa </td><td class="l">Ector County, Texas </td><td class="c">1929</td></tr>
<tr><td class="l">Henbury </td><td class="l">McDonnell Ranges, Central Australia </td><td class="c">1932</td></tr>
<tr><td class="l">Wabar </td><td class="l">Rub’ al Khali, Arabia </td><td class="c">1932</td></tr>
<tr><td class="l">Campo del Cielo </td><td class="l">Gran Chaco, Argentina </td><td class="c">1933</td></tr>
<tr><td class="l"><a class="fn" id="fr_2" href="#fn_2">[2]</a>Haviland (Brenham) </td><td class="l">Kiowa County, Kansas </td><td class="c">1933</td></tr>
<tr><td class="l">Mount Darwin </td><td class="l">Tasmania </td><td class="c">1933</td></tr>
<tr><td class="l"><a class="fn" id="fr_3" href="#fn_3">[3]</a>Podkamennaya Tunguska </td><td class="l">Yeniseisk District, Siberia </td><td class="c">1933</td></tr>
<tr><td class="l">Box Hole Station </td><td class="l">Plenty River, Central Australia </td><td class="c">1937</td></tr>
<tr><td class="l">Kaalijarv </td><td class="l">Oesel, Estonia </td><td class="c">1937</td></tr>
<tr><td class="l">Dalgaranga </td><td class="l">Western Australia </td><td class="c">1938</td></tr>
<tr><td class="l">Ussuri (Sikhote-Alin) </td><td class="l">Eastern Siberia </td><td class="c">1947</td></tr>
<tr><td class="l">Wolf Creek </td><td class="l">Wyndham, Kimberley, Western Australia </td><td class="c">1948</td></tr>
<tr><td class="l">Aouelloul </td><td class="l">Adrar, Western Sahara </td><td class="c">1952</td></tr>
</table>
<div class="pb" id="Page_66">66</div>
<h2 id="c6"><span class="small">5. HEAVEN KNOWS WHERE OR WHEN</span></h2>
<p>Meteorites have been falling upon our planet for a long
time—how long, it is hard to say with accuracy. Up to now, no
specimens certainly identified as meteorites have been found in
ancient rock layers. Scientists have been able, however, to estimate
the age of several meteorite craters on the basis of the degree
of weathering not only of the crater rims, but also of the
meteorites found around the craters. Age estimates have also
been based on the ages of fossils found in silted-up crater interiors
and on other related indirect evidence.</p>
<p>As we have already noted, the Canyon Diablo, Arizona,
crater is thought to be 20,000 to 70,000 years old. The Odessa,
Texas, crater is at least 200,000 years old; and the Haviland
(Brenham), Kansas, craters more than 600,000 years old.
Clearly, meteorite falls have been occurring over a very long
period of earth history.</p>
<p>For many years, scientists have studied the distribution of recovered
meteorites around the world in an effort to find out
whether there are any places on the land surface of our globe
where meteorites have fallen in unusually large numbers.</p>
<p>The idea that any particular spot on the land surface of the
earth might in some way attract more meteorites to it than
other locations seems unreasonable because of the very nature
of the target presented by our planet to the meteorites wandering
through space. Not only is the earth in motion, but it is in
<span class="pb" id="Page_67">67</span>
very complicated motion. Our earth revolves about a sun which
is also in motion through space. At the same time, the earth is
rotating on its axis. A single point on the surface of the earth
therefore traces a very erratic path in space with the passage of
the years, and the likelihood that this particular point would be
struck by more than one meteorite (if indeed by one!) must be
very small.</p>
<p>Studies have shown that the people of the earth have a great
deal more to do with “concentrations” of meteorite recoveries
than anything else. <i>Population density</i> is the first important factor.
Clearly, the more people living in a given area, the higher
the probability that a meteorite fall will be seen and reported
and that the fallen mass itself will be recovered. A prime example
is India, one of the most densely populated regions of the
world. Of the 102 meteorites recovered in that country up to
1953, 97 were of witnessed fall. This extremely high proportion
of falls is undoubtedly due to the fact that for centuries such
an event could hardly have taken place in that country without
attracting the attention of large numbers of people. Apparently,
the majority of Indian meteorites have been recovered as they
fell, for only 5 unwitnessed falls are recorded for that country.</p>
<p>On the other hand, from French West Africa only 5 falls and
3 finds have been reported throughout an area slightly larger
even than India’s. This country thus provides an example of a
sparsely populated region, in many provinces of which a meteorite
fall might pass unobserved, and a fallen meteorite might
remain undiscovered.</p>
<p>A second factor is the <i>degree of civilization</i> reached by the
<span class="pb" id="Page_68">68</span>
inhabitants of a particular area. Those regions of the world
which have been settled the longest and which have seen the
development of the higher cultures will be the most likely to
support a populace that will take an interest in and report the
occurrences of natural events like meteorite falls. Such a populace
will also be more likely to bring suspected meteorites to
the attention of experts.</p>
<p>For example, up to 1953, 55 witnessed falls and 3 unwitnessed
falls were known from France, a country of relatively small
area, but with a high population density and an advanced degree
of civilization. From the whole vast area of Siberia, on the
other hand, only 20 meteorite falls and 23 finds have been reported
during the same interval.</p>
<p>In the past, scientists have suggested that various natural
forces, such as the magnetic field of the earth or the attraction
of high and massive mountain ranges, might cause more meteorites
to fall in one place than another. But all available evidence
indicates that this is not the case. The fall of meteorites upon
the earth has been and is a process that shows no apparent pattern.
Only “human” factors (like population density and scientific
interest in meteorites) can be considered as accounting for
any concentrations of meteorite falls in particular regions or
countries.</p>
<p>In historic times, the number of man-built structures (houses,
barns, hotels, office buildings, etc.) has increased tremendously.
Such structures have presented an ever-expanding target to hits
by falling meteorites. On pages <a href="#Page_73">73</a>, <a href="#Page_74">74</a> is a listing of some of
the meteorites that have struck and damaged buildings during
<span class="pb" id="Page_69">69</span>
the last 150 years or so. The items included in this list were
chosen on the basis of interest, authenticity, and concreteness
of detail.</p>
<p>The stories of all these meteorite falls are exciting, but none
more so, perhaps, than that of the Beddgelert, North Wales,
stone. This meteorite fell in the small hours of the morning on
September 21, 1949. Not many people saw the fireball that accompanied
its descent because of the early hour (1:45 a.m.),
but one of the few persons who happened to be outside said that
it resembled a huge rocket as it flashed across the sky. He also
reported that the appearance of the fireball nearly frightened
the swans in the local park to death, the birds fleeing in all
directions.</p>
<p>The manager of one of the hotels in Beddgelert simultaneously
was awakened from a sound sleep by the barking of his
dog. This was an unusual occurrence, and the man was surprised
by it. While he was trying to account for the dog’s peculiar behavior,
he suddenly realized that something quite out of the ordinary
was happening outside. He heard a series of unevenly
spaced bangs that he later compared to “a naval broadside.”
But as the noise died away and nothing further happened, he
went back to sleep.</p>
<p>About noon on the next day, the manager’s wife went into
the upstairs lounge of the hotel, a room right under a part of
the roof. She was astonished to find plaster dust all over the
floor. It had obviously come from a jagged hole in the ceiling.
And, on the floor, she found an odd-looking dark stone.</p>
<p>Investigation showed that this stone had indeed fallen through
<span class="pb" id="Page_70">70</span>
the roof. It had made a neat round hole in four overlapping
thicknesses of slate, shattered the underlying lath, made a dent
in the lower edge of an H-section iron girder, and had finally
broken through the plaster ceiling into the hotel’s upstairs
lounge.</p>
<p>Although it was clear that the stone had come through the
roof, the hotel manager did not connect the event in any way
with the peculiar noises he had heard during the preceding night.</p>
<p>He tried to cut the stone on an emery wheel, but it was too
hard.</p>
<p>That evening, an old miner in the hotel restaurant recognized
the stone as a meteorite. Many years before, he had visited
a museum and had seen specimens of meteorites on display
there.</p>
<p>The slabs of slate penetrated by the meteorite would have
provided good evidence as to the speed of the cosmic missile at
the time it struck the roof. But, unfortunately, these appear to
have been thrown away at the time the roof was repaired. This
fact is mentioned to show that important scientific evidence is
sometimes unwittingly destroyed before investigators can get a
chance to examine it.</p>
<p>Along with the rapid increase in the number of man-made
buildings has, of course, gone a simultaneous increase in the
world’s population itself. A person does not present as large a
target to a falling meteorite as a house or barn, but even so, if
there were enough people on the earth, it would seem that someone
was bound to be hit sooner or later.</p>
<div class="pb" id="Page_71">71</div>
<div class="img" id="fig23">
<img src="images/p23.jpg" alt="" width="800" height="783" />
<p class="pcap"><span class="jr">G. W. SWINDEL, JR. PHOTO</span>
<span class="jr">COURTESY OF ALABAMA MUSEUM OF NATURAL HISTORY</span>
The Sylacauga, Alabama, stone meteorite and the roof (note circle)
through which it plunged and struck a person.</p>
</div>
<div class="pb" id="Page_72">72</div>
<p>Actually, the first <i>authentic</i> case of a person being struck by
a meteorite did not occur until November 30, 1954. Even then,
the hit was an indirect one. At Sylacauga, Alabama, a meteorite
fell through the roof of a house, went through the ceiling of
the living room, struck the top of a radio, and—bouncing in a
6-foot arc—hit the lady of the house, who was taking a nap on
the couch. Fortunately, nearly all of the energy of the meteorite
was spent by the time it struck the woman, and, moreover, she
was covered with two heavy quilts so that she was not critically
injured. But she did receive bruises serious enough to send her
to the hospital.</p>
<p>The instances just given show that a number of meteorites
have struck buildings and, in one case, a cosmic missile has hit
a human being. Nevertheless, such events are really quite rare.
In fact, mathematical calculations indicate that, on the average,
we can expect one meteorite to fall per township (36 square
miles) per 1000 years. A rate like this does not justify the loss
of any sleep over the possibility that you might some time be hit
by a falling meteorite!</p>
<div class="pb" id="Page_73">73</div>
<div class="pb" id="Page_74">74</div>
<h3>SELECTED LIST OF METEORITES THAT HAVE STRUCK AND DAMAGED BUILDINGS</h3>
<table class="center" summary="">
<tr class="th"><th><span class="small">NAME AND LOCATION</span> </th><th class="l"><span class="small">TYPE</span> </th><th class="r"><span class="small">APPROXIMATE WEIGHT</span> </th><th class="r"><span class="small">YEAR</span></th></tr>
<tr><td class="l">Baxter, Missouri </td><td class="l">stone </td><td class="r">611 gm.<a class="fn" id="fr_4" href="#fn_4">[4]</a> </td><td class="r">1916</td></tr>
<tr><td class="j" colspan="4">Meteorite penetrated roof and struck a log joist, which checked the fall. The stone lodged in the attic.</td></tr>
<tr><td class="l">Beddgelert, North Wales </td><td class="l">stone </td><td class="r">794 gm. </td><td class="r">1949</td></tr>
<tr><td class="j" colspan="4">Meteorite made a clean hole through 4 thicknesses of slate roof. It then shattered underlying wood, made tiny dent in bottom edge of H-section iron girder, and broke through plaster ceiling into hotel lounge below.</td></tr>
<tr><td class="l">Benld, Illinois </td><td class="l">stone </td><td class="r">1770 gm. </td><td class="r">1938</td></tr>
<tr><td class="j" colspan="4">Meteorite penetrated garage roof, top of car, and seat cushion. It struck and put 1-inch dent in muffler, then bounded back up and became entangled in seat cushion springs.</td></tr>
<tr><td class="l">Bethlehem, New York </td><td class="l">stone </td><td class="r">11 gm. </td><td class="r">1859</td></tr>
<tr><td class="j" colspan="4">Meteorite struck the side of wagon house, bounded off, hit log upon ground, bounded again, and rolled into the grass. (A dog lying in the doorway of the wagon house jumped up, ran out and seized the meteorite, but dropped it right away, probably because of the warmth and sulfurous odor of the stone.)</td></tr>
<tr><td class="l">Branau, Bohemia </td><td class="l">iron </td><td class="r">19,000 gm. </td><td class="r">1847</td></tr>
<tr><td class="j" colspan="4">Meteorite penetrated into room where 3 children were sleeping and covered them with plaster and debris. They were unharmed.</td></tr>
<tr><td class="l">Constantia, South Africa </td><td class="l">stone </td><td class="r">999 gm. </td><td class="r">1906</td></tr>
<tr><td class="j" colspan="4">Meteorite penetrated 2 thicknesses of corrugated iron roofing and smashed ceiling.</td></tr>
<tr><td class="l">Kasamatsu, Japan </td><td class="l">stone </td><td class="r">721 gm. </td><td class="r">1938</td></tr>
<tr><td class="j" colspan="4">Meteorite penetrated roof of house and stopped on floor. It went through roof tile, ⅓-inch wooden roof-panel, and layer of clay 1 inch thick between them.</td></tr>
<tr><td class="l">Kilbourn, Wisconsin </td><td class="l">stone </td><td class="r">772 gm. </td><td class="r">1911</td></tr>
<tr><td class="j" colspan="4">Meteorite went through 3 thicknesses of shingles, a 1-inch hemlock roof board, and a ⅞-inch hemlock floor board. It then glanced in turn against the side of a manger and the stone foundation of the barn and finally penetrated 2½ inches into the clay floor of the barn.</td></tr>
<tr><td class="l">Pantar, Philippine Is. </td><td class="l">stone </td><td class="r">shower </td><td class="r">1938</td></tr>
<tr><td class="j" colspan="4">Sixteen stones were recovered; thousands “as big as corn and rice grains” fell on roofs.</td></tr>
<tr><td class="l">Sylacauga, Alabama </td><td class="l">stone </td><td class="r">3863 gm. </td><td class="r">1954</td></tr>
<tr><td class="j" colspan="4">Meteorite penetrated composition roof material, ¾-inch wooden decking, ¾-inch wooden ceiling, and interior wallboard. It then hit a radio, punching a 1-inch hole in plywood top, and bounced 90° towards the east, striking woman lying on couch.</td></tr>
</table>
<div class="pb" id="Page_75">75</div>
<h2 id="c7"><span class="small">6. FINDERS FOOLISH, FINDERS WISE</span></h2>
<p>People find a great many meteorites that were not seen to
fall. Most of these landed on the surface of the earth at some
time in the remote past or happened to fall in an originally unpopulated
portion of the land area of the globe. Generally, such
meteorites are discovered entirely by accident, although in recent
years quite a few recoveries of unwitnessed falls have been
made by design. This has been the case during the systematic
surveys with meteorite detectors conducted around such recognized
meteorite crater areas as Canyon Diablo, Arizona; Odessa,
Texas; and Wolf Creek, Australia.</p>
<p>The different modes of discovery of meteorites not seen to
fall are interesting in themselves. The largest percentage of finds
has unquestionably been made by farmers. The Plymouth, Indiana,
meteorite, for example, was plowed up or, as the farmer
nursing the rib bruised by his bucking plow would probably
prefer to say, “plowed into.” So were such meteorites as the
Algoma, Wisconsin; the Bridgewater, North Carolina; the Carlton,
Texas; and the Chesterfield, South Carolina, to name only
a few. A farmer found the Kenton, Kentucky, iron while he was
cleaning out a spring. Another farmer was removing debris
from an abandoned water well in an attempt to revive it when
he discovered the Richland, Texas, iron. A field drainage project
brought the Seeläsgen, Poland, iron to light. A man planting an
apple tree near his house dug out the Mount Joy, Pennsylvania,
<span class="pb" id="Page_76">76</span>
iron, and a farmer hoeing tobacco turned up the Scottsville,
Kentucky, iron.</p>
<p>The second largest percentage of finds probably has been
made by miners. Prospectors and placer miners have mistaken
numerous iron meteorites for lumps of silver ore. Among these
are the Murfreesboro, Tennessee; Lick Creek, North Carolina;
and Illinois Gulch, Montana, irons. The Aggie Creek, Alaska,
iron was raised by a gold dredge. The gold miners recognized
this meteorite as an unusual “haul” when it announced its presence
by clanging loudly on the metallic screen of the dredge.</p>
<p>Men at work on road construction are also to be thanked for
chancing upon meteorites of unwitnessed fall, for example, the
irons found by road crews at Bear Lodge, Wyoming, and at
Bald Eagle, Pennsylvania.</p>
<p>Some meteorites have been “found twice.” At Opava, Czechoslovakia,
archeologists discovered seven pieces of meteoritic
iron in a buried Stone Age campsite—the oldest meteorite collection
so far on record! Apparently the paleolithic inhabitants
of the Opava region had gathered the heavy masses together and
used them to bolster the fireplaces in their rude encampment.</p>
<p>Investigators discovered the Mesaverde, Colorado, iron in the
Sun Shrine on the north side of the Pipe Shrine House, and the
Casas Grandes, Mexico, iron in the middle of a large room of
the Montezuma temple ruins, carefully wrapped in linen cloth
like a mummy. Members of an early archeological survey found
the small Anderson Township, Ohio, meteoritic specimens on
altars in mounds of the Little Miami Valley group of prehistoric
earthworks. Some scientists believe that the American Indians
transported these specimens to Ohio from the site of the Brenham
meteorites in Kiowa County, Kansas.</p>
<div class="pb" id="Page_77">77</div>
<div class="img" id="fig24">
<img src="images/p24.jpg" alt="" width="800" height="720" />
<p class="pcap">The Lake Murray, Oklahoma, iron meteorite in place, just as it was
found. See <a href="#Page_80">p. 80</a>.</p>
</div>
<div class="pb" id="Page_78">78</div>
<p>Other modes of discovery fall into no pattern and must be
regarded as merely curious. A farmer plowing his field near
Pittsburgh, Pennsylvania, came across a snake. In looking for a
suitable stone with which to kill it, he first seized upon a mass
of iron too heavy to lift. After he had killed the snake with a
handy rock, the farmer’s attention was drawn back to the small
but remarkably heavy mass he had first tried to pick up. He
carted it off to the city, where eventually it was recognized as
a meteorite.</p>
<p>In another unusual recovery, fishermen brought the Lake
Okeechobee, Florida, stone up from the waters of the lake in
a net—the only such recovery recorded in the whole literature
of meteoritics, although three-fourths of all meteorites must necessarily
fall into water on our ocean-covered globe. Again, the
members of the Australasian Antarctic Expedition of 1911-1914
were surprised to find the Adelie Land, Antarctica, stone lying
on the snow some 20 miles west of Cape Denison.</p>
<p>Because the true nature of meteorite finds has often been
unrecognized—sometimes for many years—these masses have
been put to some rather lowly uses. The finder of the Rafrüti,
Switzerland, iron meteorite used it as a footwarmer, and many
of the heavy irons have been employed as haystack, fence, and
barrel-cover weights, or as anvils, nutcrackers, and doorstops.</p>
<div class="pb" id="Page_79">79</div>
<div class="img" id="fig25">
<img src="images/p25.jpg" alt="" width="800" height="637" />
<p class="pcap">It’s a whopper! See <a href="#Page_80">p. 80</a>.</p>
</div>
<div class="pb" id="Page_80">80</div>
<p>Some have fared better, as did the 1,375-pound La Caille,
France, meteorite, which the people of the village used for two
centuries as a seat in front of their church. Others, however,
have fared even worse. Blacksmiths and assayers have smelted
up and destroyed a number of iron meteorites either in the making
of tools (like plowshares, axe-heads, and knife-blades) or
in the quest for precious metals. Nearly all of the iron meteorite
that was found by the farmer near Pittsburgh was worked up by
a blacksmith and lost to science. Even the stone meteorites have
occasionally fallen victims to man’s greed for gold. Miners who
believed that the 80-pound San Emigdio, California, stony meteorite
was gold-bearing mashed it to powder in an ore-crusher.</p>
<p>On the contrary, people who, in one way or another, have
become acquainted with the characteristics of meteorites have
brought a number of these objects to the attention of scientists.
For example, one of the University of Nebraska men who
worked on the excavation and removal of the large Furnas
County stone meteorite (see <a href="#c3">Chapter 2</a>) became keenly interested
at that time in meteorites in general, and took the trouble
to learn as much as he could about them. Several years later,
after he had become director of a state park museum in southern
Oklahoma, a large metallic mass was reported to him. The finder
of this mass of metal had known of its existence for some 20
years, but had never succeeded in getting anyone to examine it
carefully. The former field worker took one look at the object
and, on the basis of his knowledge of meteorites, concluded that
it probably was a huge iron meteorite. He immediately called
the Institute of Meteoritics by long distance and was able to give
such a wealth of significant details that a field party left at once
for the site. In this way, the Lake Murray, Oklahoma, meteorite
was identified and recovered.</p>
<div class="pb" id="Page_81">81</div>
<div class="img" id="fig26">
<img src="images/p26.jpg" alt="" width="800" height="649" />
<p class="pcap">The Lake Murray core mounted on the meteorite saw which cut it
in half. One of the worn soft iron saw-blades is held above the
meteorite by the saw guides. See pp. <a href="#Page_167">167</a>, <a href="#Page_168">168</a>.</p>
</div>
<div class="pb" id="Page_82">82</div>
<p>The unoxidized central core of this iron weighed more than
600 pounds. Before excavation this core was surrounded by a
“shell” of oxidized meteoritic material several inches thick, as
shown on <a href="#Page_77">page 77</a>. Such a shell of oxide clearly indicated that
the meteorite had been subjected to weathering in the ground
for many thousands of years.</p>
<p>In general, meteorites <i>seen to fall</i>—possibly because of the
magnitude and impressiveness of the light and sound effects
connected with their descent—have received respectful treatment
after recovery. Most of them have been presented to men
of science for study and eventual display in some museum collection.
Even when kept by their finders, the specimens usually
have been well cared for. After the fall of the Flows, North
Carolina, meteorite in 1849, the owner of the land on which it
came down set the stone in a place of honor on top of a barrel
fixed to a post. On the post he put up the notice:</p>
<blockquote>
<p>“<i>Gentlemen, sirs—please not to break this rock,
which fell from the skies and weighs 19.5 pounds.</i>”</p>
</blockquote>
<p>This landowner
obviously realized that nearly everyone has the unfortunate urge
to hammer on strange rocks.</p>
<p>Of course, there have been exceptions to the respectful treatment
of meteorites seen to fall. The finder of one fragment of
the Zhovtnevy Hutor, Russia, fall tossed it into the stove, and a
farm woman lost another by throwing it at an unruly horse. A
peasant who thought meteorites possessed miraculous powers
powdered up a piece of the diamond-bearing Novo-Urei, Russia,
stone and ate it!</p>
<div class="pb" id="Page_83">83</div>
<div class="img" id="fig27">
<img src="images/p27.jpg" alt="" width="800" height="597" />
<p class="pcap">A polished and etched face of the Lake Murray meteorite. The
length of the cut is a good 23 inches.</p>
</div>
<div class="pb" id="Page_84">84</div>
<h2 id="c8"><span class="small">7. LANDMARKS, SKYMARKS & DETECTORS</span></h2>
<p>The chemist can easily obtain materials for his research
work from reliable supply houses. The meteoriticist (as a scientist
who studies meteors and meteorites is known), is not this lucky.
He must search for the specimens he wishes to investigate wherever
they may have landed on the wide, wide earth. This “needle-in-a-haystack”
problem could rarely be solved if it were not for
certain mathematical and instrumental aids that swing the balance
in favor of the meteorite hunter. When meteorites are seen
to fall, these aids can be brought into play only if certain information
is supplied by eyewitnesses of the falls. For this reason,
everyone ought to be acquainted with the facts about meteorite
falls that scientists will need to know in order to make finds, and
should understand how these facts must be reported in order to
be of maximum use to field parties.<a class="fn" id="fr_5" href="#fn_5">[5]</a></p>
<p>The problem of working out the path a fireball has followed
in the sky boils down to this. The investigating scientists must
be able to fix the position <i>in space</i> of certain important points
on the fireball’s path. This idea of fixing points is not really difficult
at all. Suppose, to take an analogy from baseball, we have
base runners on first and third. These two players are intently
watching their team’s clean-up hitter, who is “crowding the
plate.” Consequently their lines of sight intersect at home plate
and give a very good “fix on” its position, as navigators say. This
is the way a fix can be obtained in <i>two</i> dimensions; that is, essentially,
in the plane of the earth’s surface.</p>
<div class="pb" id="Page_85">85</div>
<div class="img" id="fig28">
<img src="images/p28.jpg" alt="" width="800" height="354" />
<p class="pcap"><b>A.</b> A fix determined in two dimensions. The lines of sight of the
runners on first and third intersect at <b>x</b>.</p>
<p class="pcap"><b>B.</b> A fix determined in three dimensions. The lines of sight of the
runners on the first and third intersect at <b>x</b>.</p>
</div>
<p>Now, let us move into the <i>third</i> dimension, since a fireball’s
path through the atmosphere lies in space, not in the “flat” plane
of the earth’s surface. Returning to our baseball diamond, let us
suppose that a helicopter with an enterprising photographer
aboard hovers over the centerfield bleachers so that he can take
pictures of the record crowd. While the umpire is dusting off
home plate, the two runners on first and third simultaneously
sneak a look to see what the helicopter is doing. Their lines of
<span class="pb" id="Page_86">86</span>
sight now intersect at the helicopter and fix its position <i>in space</i>.</p>
<p>Similarly, the location of a fireball path in space is determined
by the fixing of certain points on the luminous streak seen in the
sky. Instead of using only two intersecting lines of sight (those
of the runners on first and third in our analogy), scientists investigating
a meteorite fall try to collect as many different lines
of sight as possible from people in the region above which the
fireball streaked. The more commonly determined points are
those of the fireball’s appearance and disappearance and those
where “explosions” took place. These points are generally located
by use of the method we have described in some detail
above, the so-called <i>intersecting-lines-of-sight</i> method.</p>
<p>The most important point on a fireball path is the point of
disappearance. The most valuable single piece of information
you can supply about a meteorite fall is as accurate an answer
as possible to the question: In what compass direction were you
looking when you <i>last</i> saw the fireball? This question has often
been twisted around in newspaper and radio accounts into the
meaningless question: In what direction was the fireball going
when you saw it?</p>
<p>One person cannot give the answer to the second question
because from a single station it is impossible to determine the
<i>true</i> direction of motion of an object seen in the sky. One person
can report only an <i>apparent</i> direction of motion, which is of
little or no value in locating the last point on the luminous path,
generally referred to as the “end-point.” Therefore, though you
cannot by yourself determine the actual direction in which a
fireball is <i>moving</i>, you can report the direction in which you
<span class="pb" id="Page_87">87</span>
were <i>looking</i> when you last saw the fireball, that is, due south,
southwest, northeast, etc.</p>
<div class="img" id="fig29">
<img src="images/p29.jpg" alt="" width="800" height="452" />
<p class="pcap"><b>O</b> is an observer squinting along the top of a ping-pong table. A
ping-pong ball rolls along the top of the table from <b>B</b> (beginning)
to <b>E</b> (end). To the observer at <b>O</b>, however, the ball would appear to
start at <b>B</b> and end at <b>E</b> if it rolled along any one of the dashed lines
leading from <b>OB</b> to <b>OE</b>. By means of a similar space-figure, it can
be shown that a single observer at <b>O</b> cannot determine the <i>true</i> direction
of motion of a luminous object in the sky, like a meteor.</p>
</div>
<p>Scientists are eager to obtain reliable reports on the compass
direction to the fireball’s point of disappearance from as many
widely separated eyewitnesses as possible. They then can plot
the individual lines of sight on a good map, marking exactly
where these lines intersect. In this way, the investigators can
<span class="pb" id="Page_88">88</span>
make reasonably accurate fixes of the position of the point on
the earth’s surface that is situated directly below the end-point
of the fireball path, as this end-point was seen in the sky by each
pair of eyewitnesses.</p>
<p>Instead of using the ordinary compass direction to a fireball’s
point of disappearance, you may prefer, as do astronomers, to
use the azimuth. What we have been calling a “compass direction”
is one that is expressed in terms of the cardinal points:
north, south, east, west. An azimuth is a direction stated in <i>degrees</i>.
Rough azimuths can be taken with a compass, but for
accurate work, a graduated circle, like that on a transit or theodolite,
must be used. Astronomical azimuths begin at the <i>south</i>
point and continue clockwise full circle to 360°. For example,
the lines of sight in the diagram, <a href="#Page_87">p. 87</a>, could very well have
been given as astronomical azimuths. And, in the diagram, <a href="#Page_91">p. 91</a>,
the line of sight C₁ could have had the precise designation 118°
and C₂ that of 222°.</p>
<p>Every fix serves to guide field parties to areas that are to be
carefully searched for fallen meteorites. Extra-thorough searches
are made if the people living in a particular area reported that
they heard meteorite fragments hissing and whining on their
way to earth or heard the thumps of their impacts on the ground.</p>
<p>You will notice that so far we have been treating our problem
as a two-dimensional one. We have been working with <i>directions</i>
only and have plotted out direction indicators on a map
representing the plane of the earth’s surface. Now, as we did in
our baseball analogy, let us move into the third dimension.</p>
<div class="pb" id="Page_89">89</div>
<div class="img" id="fig30">
<img src="images/p30.jpg" alt="" width="800" height="440" />
<p class="pcap">Diagram (not drawn to scale) showing plotted compass directions
to the last visible point on a fireball path. (The point denoted by <b>L</b>
in <a href="#fig30">next diagram</a>.) Black dots represent positions of various observers.
Each arrowed line is directed toward the last visible point as it
was estimated by the individual observer. The oval area, which includes
points of intersection of all observed lines of sight taken in
pairs, marks out region in which meteorites have probably fallen.</p>
</div>
<div class="pb" id="Page_90">90</div>
<p>If, in addition to compass directions to the observed endpoint,
scientists can also obtain the apparent <i>elevation</i>, in degrees,
of this point as seen by the various eyewitnesses, then
with the help of a little trigonometry, they can fix the position
<i>in space</i> of the end-point itself rather than the position of its
<i>projection</i> on the surface of the earth.</p>
<p>This same procedure can be followed in fixing the space-position
of any well-observed point on the fireball path. It therefore
becomes possible when <i>both</i> elevations and compass directions
are reported for several points on the fireball path to determine
the flight-path or, as it is technically called, the <i>trajectory</i>, of
the falling meteorite through the atmosphere. Trajectory determinations
are of great scientific value.</p>
<p>You can estimate the compass directions and elevations to
the important points on a meteorite trajectory at the actual time
of fall. Or you can have the scientific field party make or check
your measurement at some later time by setting up a surveying
instrument at the very point from which you saw the fireball.</p>
<p>The accuracy of your measurements can be improved if you
have been able to “line up” the point, L, at which you saw the
fireball disappear, with some familiar object on the horizon,
such as a church steeple, a tall tree, a telephone pole, or a lightning
rod on a farm building. You will recall that an eleven-year
old girl provided one of the field parties from the Institute of
Meteoritics with an excellent observation of the point of disappearance
of the Norton fireball. She was able to do this because
she remembered just where it went out of sight behind a familiar
landmark.</p>
<div class="pb" id="Page_91">91</div>
<div class="img" id="fig31">
<img src="images/p31.jpg" alt="" width="800" height="426" />
<p class="pcap">Method for locating a point on a fireball path. (In this case the point
of disappearance, <b>L</b>.)</p>
<dl class="undent pcap"><dt>O₁ First observer.</dt>
<dt>A₁ Apparent height of point of disappearance (50°).</dt>
<dt>C₁ Compass direction of point of disappearance (N 62° W).</dt>
<dt>O₂ Second observer.</dt>
<dt>A₂ Apparent height of point of disappearance (45°).</dt>
<dt>C₂ Compass direction of point of disappearance (N 42° E).</dt></dl>
</div>
<div class="pb" id="Page_92">92</div>
<p>If the fall occurs at night, you can help investigators greatly
if you are familiar enough with the brighter stars to use them
as “skymarks.” You simply note as quickly and sharply as you
can just where the fireball path was in reference to those prominent
stars. This alert observation of yours will at least be a great
aid to investigators who are searching for meteorites that may
have fallen from the fireball; and, moreover, there is no telling
what else your quick eye might have captured for science.</p>
<p>While looking through a window, Kayser, the Polish astronomer,
saw a fireball appear at Rigel and move to Sirius, where it
disappeared. This observation of his proved to be one of the
most accurate and <i>significant</i> ever made of the fall of a meteorite.
For it enabled the German mathematician, Galle, to show
that the Pultusk meteorite, which produced the fireball Kayser
saw, came into the Solar System from interstellar space!</p>
<p>It is very essential to carefully notice and mark the exact spot
from which your observation was made so that you can return
to it if scientists wish to set up surveying instruments there.</p>
<p>The map and side view of the Norton County, Kansas, meteorite
trajectory show the practical results that the Institute obtained
by use of the intersecting-lines-of-sight method. The fireball
accompanying the Norton meteorite fall appeared at A.
The first “explosion” took place at E₁, the second at E₂, and the
fireball disappeared at L.</p>
<p>If markers were dropped straight down to earth from each
point along the trajectory or flight-path of a meteorite through
the atmosphere, the line joining the points where the markers
fell would be the <i>earth-trace</i> of this trajectory. The directions of
sight to these various points are indicated for people living in
the towns along and near the earth-trace of the Norton meteorite
fall. The solid-line arrows represent the direction of the point
of disappearance; the dotted-line arrows, the point of appearance;
the dash-dot arrows, E₁; and the dashed arrows, E₂. The
probable area of fall is shown as an oval-shaped area, the longer
axis of which is identical with the direction of motion of the
meteorite.</p>
<div class="pb" id="Page_93">93</div>
<div class="img" id="fig32">
<img src="images/p32.jpg" alt="" width="604" height="800" />
<p class="pcap">Path of the Norton meteorite.</p>
</div>
<div class="pb" id="Page_94">94</div>
<p>The many fragments of all sizes recovered from the Norton
fall were all found within the bounds of this oval-shaped area,
although unavoidable errors of observation placed the center
of the oval about 4 miles too far to the north.</p>
<p>In addition to the questions about direction and elevation,
there are a few more that investigators of meteorite falls would
like to have observers answer.</p>
<blockquote>
<p>At what time (determined as accurately as possible) did the
fall occur? Knowledge of this time is necessary if the path in
which the meteorite was moving about the sun is to be calculated
by scientists.</p>
<p>Did you hear any sounds, either while you were watching the
fireball or after it disappeared? If you heard such sounds as the
whining or hissing of meteorite fragments flying through the
air or the heavy thumps of their impacts on the earth, then you
were very close to where the meteorite came down!</p>
<p>How many minutes and seconds (again determined as accurately
as you can) passed between the time when you saw the
<span class="pb" id="Page_95">95</span>
fireball vanish and the instant when you first heard sounds from
it? Such sound data permit rough determination of the distance
from the observer to the point where the meteorite fell.</p>
<p>How long did the sounds set up by the meteorite last, and in
what direction did these sounds seem to die out?</p>
</blockquote>
<p>If you or your neighbors find fragments that you suspect are
pieces of the meteorite, these specimens should be shown to
the investigating field parties at once—preferably undisturbed
and in the very places where they fell. In any event, the suspect
masses should not be hammered on and broken up! Even
as late as 1958 in a country as science-conscious as Germany,
a beautiful stony meteorite, seen to fall and speedily found by
an alert group of children playing out of doors, was deliberately
broken up into 5 pieces in order that each of the children
(aged 9 years and up) might take home a “souvenir” of the
event. Later, these pieces had to be laboriously reassembled by
scientists before any idea could be gained of the original shape
and surface features of the meteorite.</p>
<p>Even when thorough searches are made, not all the meteorite
fragments in the area of fall may be found for many months.
But if the people living in the region have been alerted and are
on the lookout for unusual specimens or signs of meteoritic impact
(such as freshly made holes or “craters” in the ground,
shattered tree limbs, and so forth), the chances of ultimately
finding many or most of the fallen masses are good.</p>
<p>As we have already mentioned, numerous fragments of the
<span class="pb" id="Page_96">96</span>
Norton meteorite (including one weighing 130 pounds) were
found within two to three months after its fall on February 18,
1948. But the main mass was not discovered until the following
August, when a caterpillar tractor nearly tipped over into the
large impact funnel that this huge stone had made in the earth.
Fortunately, field searchers from the Institute had already talked
to one of the farmers using the tractor and had told him that
just such a “crater” might be found in the very area under cultivation.
Consequently, the crater was promptly reported.</p>
<p>In surveys concerned with the location and recovery of meteorites
<i>not</i> seen to fall, we find that sometimes meteorite fragments,
particularly the smaller ones, lie on the surface of the
ground or at shallow depth. Such fragments were probably too
light to penetrate deep into the ground or, in the years since
their fall, the action of rain, wind, and frost has uncovered them.</p>
<p>In such cases, a party of searchers generally spreads out in
order to get over as much ground as possible and each member
of the group looks for meteorite specimens without using instrumental
aids. Visual searches of this type have been very successful,
for example, around the Canyon Diablo crater, where
almost the entire plain out to several miles from the rim once
was sprinkled with large and small fragments of meteoritic
nickel-iron. This type of meteorite hunt is of only limited effectiveness
because the specimens (or at least a part of each one)
must be visible to the searchers.</p>
<div class="pb" id="Page_97">97</div>
<div class="img" id="fig33">
<img src="images/p33.jpg" alt="" width="800" height="617" />
<p class="pcap">Collecting small surface specimens of meteorites with portable detecting
devices: a powerful alnico magnet mounted on a light wooden
sled, and a horseshoe magnet at the end of a cane. See <a href="#Page_98">p. 98</a>.</p>
</div>
<div class="pb" id="Page_98">98</div>
<p>To increase recoveries, searchers have employed, in addition
to their eyes, various types of permanent magnets, either mounted
on the end of a cane and used to probe the upper few inches of
loose soil, or dragged behind the searcher on a small, light sled.
Meteorite hunters have also used more powerful portable electromagnets
to collect large amounts of meteoritic material (both
solid iron and iron-shale) not only from the surface but also from
shallow depths. Even the best of these simple magnetic devices,
however, are useless in the detection of really deeply buried meteoritic
material.</p>
<p>Meteorites do not merely fall upon the earth (as most astronomical
textbooks still insist), but usually penetrate into it—often
quite deeply. In fact, one of our mathematical investigations
showed that perhaps 100,000 times as much meteoritic
nickel-iron is concentrated below maximum plow-depth (approximately
one foot) as lies above that depth. Clearly, some
form of instrument capable of detecting deeply buried meteorites
needed to be devised if this wealth of buried material was
not to be lost to science. This need was answered by the development
of special <i>meteorite detectors</i>.</p>
<p>Although meteorite detectors working on several different
principles have been constructed, we shall limit attention here
to the simplest and most field-worthy design. The essential principle
on which it operates is one familiar to any Boy or Girl
Scout who has used a magnetic compass. The first lesson Scoutmasters
teach is not to read compass directions from such an
instrument when it is held near a mass of iron of considerable
size, such as an automobile. Such a large iron mass alters or
distorts the local magnetic field of the earth on which the direction-finding
ability of the ordinary compass depends. It is this
very characteristic, so bothersome to the user of a compass, that
is the principle on which meteorite detectors work. For if an
electrically driven meteorite detector capable of generating its
own magnetic field is carried over a deeply buried iron meteorite,
the instrument’s magnetic field will be distorted by the presence
of the metal mass, just as the local magnetic field of the
earth was distorted by the metal of the automobile.</p>
<div class="pb" id="Page_99">99</div>
<div class="img" id="fig34">
<img src="images/p34.jpg" alt="" width="394" height="800" />
<p class="pcap">A 146-pound iron, found by this girl without the use of instruments
although only a small corner of the meteorite was visible above the
surface of the ground.</p>
</div>
<div class="img" id="fig35">
<img src="images/p34a.jpg" alt="" width="574" height="800" />
<p class="pcap">A commercially built meteorite detector in operation.</p>
</div>
<div class="pb" id="Page_100">100</div>
<p>The operator of such a meteorite detector wears earphones
and watches a signal needle in plain sight on the top panel of
the detector. Since the phone and signal-needle circuits of the
meteorite detector are <i>in balance</i> only when the magnetic field
generated by the detector is undistorted, the disturbing presence
of a deeply buried meteorite is at once revealed by a shrill note
sounding in the earphones and simultaneous motion of the signal
needle. If, as in all buried treasure stories, we use “X” to
stand for the spot where the signals from the detector are strongest,
then the meteorite-hunter has only to dig deep enough at
“X” to recover the celestial treasure-trove he is after.</p>
<div class="pb" id="Page_101">101</div>
<h2 id="c9"><span class="small">8. THE NATURE OF METEORS</span></h2>
<p>In answer to an exam question, a freshman astronomy student
wrote:</p>
<div class="verse">
<p class="t0">A <i>meteor</i> is the flash of light</p>
<p class="t0">Made by a falling <i>meteorite</i></p>
<p class="t0">As it rushes through the air in flight—</p>
<p class="t0">I hope to gosh this answer’s right!</p>
</div>
<p>Doggerel or not, the student’s definition correctly stated the true
distinction between the two terms, and the teacher marked his
off-beat answer correct.</p>
<p>Defined in more scientific terms, a meteor is the streak of
light (usually of brief duration) that accompanies the flight of
a particle of matter from outer space through our atmosphere.
This particle may be as small as a tiny dust grain or as large as
one of the minor planets which are called asteroids. Fortunately
for the inhabitants of the earth, most of the meteor-forming
masses encountered by our globe are of the “small-fry” variety!</p>
<p>As the rapidly moving particle plunges earthward through
denser and denser layers of atmosphere, the air molecules offer
ever-increasing resistance to its passage. This resistance heats
up the meteorite body until it glows. Technically speaking, it becomes
incandescent. <i>The meteor is this incandescence.</i> We see
it as a darting point. Or as a ball of white, orange, bluish, or
reddish light. But the <i>material object</i> that produced this light is
the <i>meteorite</i>. The distinction between these two terms—meteor
and meteorite—we must emphasize again and again because
people continue to use them incorrectly, as, for instance, when
<span class="pb" id="Page_102">102</span>
they keep saying “meteor crater” instead of “meteorite crater.”</p>
<p>The majority of the meteors we observe represent the heat-induced
“evaporation” of exceedingly small fragments of cosmic
matter. The smallest meteor-forming bodies reach the surface
of the earth only as the finest of dust particles or as microscopic
droplets of solidified meteorite melt.</p>
<p>These residues descend slowly through the atmosphere and
may be carried for great distances. Afterwards, they may be
found scattered so widely and uniformly on the ground that their
presence in any given locality cannot be accounted for by the fall
of any specific meteorite. This is a fact that, for example, one
school of modern Russian meteoriticists overlooked when they
were dealing with tiny granules of meteoritic dust that had been
recently found at Podkamennaya Tunguska. These scientists
tried to identify the tiny granules with the meteorite that had
fallen there, June 30, 1908. But the members of the latest (1958)
Russian expedition to that region about the impact point of
1908 clearly recognize the widespread character of meteoritic
dust. So they reject the theory that such dust found in the Podkamennaya
Tunguska area is specifically connected with the
meteorite that fell there a half century ago.</p>
<p>If sizable chunks of meteoritic material enter the atmosphere,
they may produce exceptionally large and brilliant meteors.
A spectacular meteor is generally known as a “fireball” if it is
as bright as Venus or Jupiter. It receives the French term <i>bolide</i>
if, in addition to showing great brilliance, its flight is accompanied
by detonations like the alarming sounds heard at the
time of the Ussuri and Norton meteorite falls.</p>
<div class="pb" id="Page_103">103</div>
<div class="img" id="fig36">
<img src="images/p35.jpg" alt="" width="800" height="808" />
<p class="pcap"><span class="jr">COURTESY OF UNIVERSITY OF NEW MEXICO PRESS</span>
A bright Giacobinid meteor, photographed from a B-29 during the
shower of October 9, 1946. See <a href="#Page_115">p. 115</a>.</p>
</div>
<div class="pb" id="Page_104">104</div>
<p>The term “shooting star,” which is often applied to meteors,
in newspapers and magazine articles, is a misnomer. A meteor
is <i>not</i> a distant sun (that is, a star) in rapid motion, for the
whole path of the meteor lies close at hand within a restricted
zone of the earth’s atmosphere.</p>
<p>The word “meteor” comes from the Greek word <i>meteōra</i>,
which once applied to any natural occurrence <i>in the atmosphere</i>—for
example, rainbows, halos, auroras, and so forth. Nowadays,
the word “meteor” is used in a much more specialized
sense than it was by the ancient Greeks. We have a specialized
word, <i>meteoritics</i>, for the study of meteors and meteorites. No
one should confuse meteoritics with <i>meteorology</i>, which is the
science of things <i>other</i> than meteors and meteorites, in the atmosphere—for
example, clouds, storms, air currents.</p>
<p>The region in which meteoric phenomena take place was long
the subject of controversy. Some persons felt that meteors were
nearby, like lightning. Others said that they moved at the distances
of the remote fixed stars. This controversy on the whereabouts
of meteors became heated, although it could have been
settled quickly by a simple experiment you can try out for yourself.</p>
<p>Hold a pencil against the tip of your nose and look at it first
with your right eye closed and then with your left eye closed.
Repeat this experiment with the pencil held at arm’s length. In
the first case, the pencil will seem to shift position very greatly;
in the second, although the same base line (the distance between
your eyes) is used, the pencil will seem to shift position
only slightly.</p>
<div class="pb" id="Page_105">105</div>
<p>Such an apparent shift in position is called a <i>parallactic displacement</i>,
or, simply, <i>parallax</i>. The notion of parallax is of the
greatest importance in most branches of astronomy, and it leads
(with proper instruments and a little mathematics) to exact determinations
of the distances of remote objects.</p>
<p>For our purpose, we need not go into all the interesting but
complicated details. Our experiment with the pencil shows that
if a meteor was close by, like a blinding bolt of lightning, then,
as seen by a pair of observers separated by only a few blocks,
the meteor would show a large parallax. But if this meteor was
as far away as the stars, it would show no parallax at all, no
matter how widely the pair of observers were separated on the
earth.</p>
<p>There were many clever scientists among the Greeks, and it
is quite possible that a pair of them actually tried out this simple
parallax experiment on the meteors and so were able to prove
that these beautiful light effects occurred in the high but not too
distant layers of the atmosphere. The earliest calculations of
meteor heights that are so far known, however, were made in
Bologna, Italy, in 1719 and 1745—long after the heyday of
Greek science.</p>
<p>The meteor heights found by the Italians were quite low in
the atmosphere, probably for two reasons. First, the visual (unaided-eye)
observations they had to use were made by eyewitnesses
stationed so close together that accurate fixes were impossible.
Secondly, these visual observations must have related only
to the very brightest and therefore lowest portions of the luminous
paths of the meteors through the atmosphere.</p>
<div class="pb" id="Page_106">106</div>
<p>In 1798, two German students operating from carefully
chosen and widely separated stations began the systematic observation
of meteors for parallax. They found that the height of
appearance of most meteors lay between 48 and 60 miles above
the earth’s surface. It is now known that most meteors, as observed
with the naked eye, appear at about 70 miles and disappear
at about 50 miles above the surface of the earth. These
figures, obtained from visual work, still stand in spite of the development
of such modern techniques as photographic and
radar recording of meteor paths.</p>
<p>Rarely, meteors may appear at heights of 150 or more miles
and fireballs may penetrate to within a few miles of the earth.
The average meteors, however, appear and disappear within a
well-defined, high-altitude zone in the atmosphere. Fortunately,
this atmospheric zone serves us as an effective shield against the
constant bombardment of the smaller and much more numerous
particles from outer space.</p>
<p>In earlier times, scientists thought that the particles becoming
visible as meteors must be tiny dense masses of iron or stone like
the material composing the recovered meteorites. Most modern
investigators, however, believe that the typical meteor-forming
particles may be small loosely bound-together “dust-balls”; that
is, fluffy clusters of matter held together by frozen cosmic vapors,
generally referred to simply as “ices.” In any event, these
masses are usually very small, ranging perhaps from the size of
a pinhead to that of a marble.</p>
<p>Because we cannot collect the tiny masses that are seen only
as meteors, it is impossible to determine their composition by
<span class="pb" id="Page_107">107</span>
ordinary laboratory methods. The best we can do is to observe
and record carefully the light these masses give off when they
become incandescent in their plunge through the atmosphere.</p>
<p>We can examine this meteor light by using the spectroscope
and spectrograph. Through these specially designed instruments
we can make the meteor light reveal the chemical elements present
in the incandescent masses. Each such element sends out
light rays as characteristic of its nature as fingerprints are of the
individual who made them. Photographs taken of these characteristic
light rays are called <i>spectrograms</i>, and what might be
termed the “fingerprints of light” recorded on these spectrograms
are known as <i>spectra</i>—which is the plural of the word
<i>spectrum</i>. If the source of light is a meteor, the photograph
shows a meteor spectrum.</p>
<p>From a study of a considerable number of good quality meteor
spectra, scientists have found that the principal elements in
the masses responsible for meteors are iron, calcium, manganese,
magnesium, chromium, silicon, nickel, aluminum, and
sodium.</p>
<p>As we have already noted, the resistance encountered by meteor-forming
particles as they dash through our atmosphere is
so great that they become incandescent and vaporize. These
small bodies must therefore be in very rapid motion.</p>
<p>Before we attempt to find out the nature of the paths in space
followed by meteorites, we must take into account the fact that
these bodies are observed from a station—the earth—which is
itself in rapid motion. You may have noticed that on a still day,
when rain drops fall vertically downward, the streaks they leave
<span class="pb" id="Page_108">108</span>
on the windows of a swiftly moving car are not vertical but
almost horizontal. Obviously, it would be wrong to say the rain
drops are falling from left to right or from right to left when they
are actually falling almost straight down, and it is only the forward
motion of the car that makes them leave horizontal streaks.</p>
<div class="img" id="fig37">
<img src="images/p36.jpg" alt="" width="800" height="431" />
<p class="pcap">Diagram showing meteorite moving along a “closed” (elliptic) orbit,
<b>e</b>, which intersects the earth’s orbit, <b>E</b>. Held by the gravitational
attraction of the sun, the meteorite is a permanent member of the
Solar System.</p>
</div>
<p>Similarly, neither the apparent speed nor the apparent direction
of motion of a meteorite with respect to the moving earth is
significant. The important factor is the meteorite’s velocity <i>with
respect to the sun</i> at the time the meteorite is picked up by the
earth.</p>
<div class="pb" id="Page_109">109</div>
<div class="img" id="fig38">
<img src="images/p36a.jpg" alt="" width="800" height="430" />
<p class="pcap">Diagram showing meteorite moving across the earth’s orbit, <b>E</b>,
along an “open” (hyperbolic) orbit, <b>h</b>. The meteorite is traveling
at such high velocity that it will pass right through the Solar System
and back out into space unless it should chance to collide with the
earth or another planet. The sun, however, in any case is able to
change materially the direction of motion of the transient visitor to
our Solar System.</p>
</div>
<p>This factor enables us to determine in which of two possible
kinds of path the meteorite was moving <i>before</i> it was “fielded,”
as we might say in baseball, by the earth. This factor tells us
whether the meteorite was moving about the sun in a relatively
short, closed, oval-shaped path or, instead, was following an indefinitely
long, open path which began in the depths of space and
would have returned there if the collision with the earth had
not prevented.</p>
<div class="pb" id="Page_110">110</div>
<p>Either type of path is technically called an <i>orbit</i>. The closed
orbits are what the mathematicians term <i>ellipses</i>; the open orbits,
<i>hyperbolas</i>.</p>
<p>To scientists, the nature of the orbits followed by meteorites
is most important, especially in efforts to determine the mode
and place of origin of these bodies. To rocket engineers and astronauts,
it also matters a good deal whether the meteorites encountered
on flights through space are traveling sedately along
closed orbits about the sun or are zipping swiftly along open
orbits.</p>
<p>The greater the speed of these cosmic “hot-rods,” the more
dangerous they are to space travelers. For example, a mere grain
of nickel-iron moving at 40 miles per second is quite as lethal as
a .50-caliber machine-gun slug, which, relatively speaking, is
traveling at only a snail’s pace.</p>
<p>As our earth moves along its orbit about the sun, meteoritic
bodies can run into it from any direction. The direction from
which they do approach strongly influences the speed of these
bodies as they plunge through the earth’s atmosphere. A meteorite
moving slowly about the sun in the same direction as the earth
and chancing to catch up with our globe more or less from behind
will have an observed speed of only a few miles a second.
For example, the speed calculated from Harvard meteor-photographs
of one such not-too-spectacular “rear-end” collision
amounted to no more than 7.3 miles per second, just about the
speed a rocket must acquire to escape from the apron strings of
Mother Earth.</p>
<div class="pb" id="Page_111">111</div>
<div class="img" id="fig39">
<img src="images/p37.jpg" alt="" width="800" height="472" />
<p class="pcap">Meteor shower. Earth and particle-swarm passing through the intersection
of their orbits at nearly the same moment.</p>
</div>
<p>In contrast to such a “rear-end” collision, the speed observed
would be far greater if the meteorite happened to collide exactly
“head-on” with the earth. For, in this case, the orbital speed of
our planet would be <i>added</i> to that of the meteorite about the
sun. As an example, suppose that at the earth’s average distance
from the center of our Solar System, the speed of a meteorite
with respect to the sun were 32.23 miles per second. (This speed
was actually found for the mass that produced one of the first meteors
photographed simultaneously by the Harvard stations at
Cambridge and Oak Ridge, Massachusetts.) Then if such a meteorite
ran “head-on” into the earth, the speed observed for it
<span class="pb" id="Page_112">112</span>
in the atmosphere would be over 51 miles per second. And
mathematics would show that the orbit of this meteorite with respect
to the sun was a wide open hyperbola.</p>
<p>If the orbit of the earth and the orbit of a swarm of particles of
cosmic matter intersect, and if the earth and the swarm pass
through this intersection in space at nearly the same moment,
multitudes of meteors appear. We then say that a <i>meteor shower</i>
takes place. The position of the point at which the particle-swarm
crosses the earth’s orbit about the sun fixes the date of the meteor
shower.</p>
<p>Because the particles that make a meteor shower are moving
through space along parallel paths as they come into the earth’s
atmosphere, the meteors all seem to shoot out from a single
small area in the sky. You may have seen something like this
in the case of the sunrise or sunset effect known as “the sun drawing
water.” In this more familiar phenomenon, the sun’s disk is
the area from which shafts of sunlight radiate out in a beautiful,
if somewhat irregular, fan-like pattern. The area from which the
meteors of a given shower seem to come is the <i>radiant</i> of that
shower.</p>
<p>Meteor showers are named for the constellation in which
their radiant lies. The suffix “-id” (Greek for “daughters of”),
or some modification of this suffix, is added to the name of the
constellation from which the meteors seem to radiate. The Orionid
radiant, for example, is in Orion, the Hunter; the Leonid
radiant is in Leo, the Lion; and the Lyrid radiant is in Lyra, the
Harp. Exceptions to this rule do occur, however. Astronomers
may refer to a shower sometimes appearing on the night of October
9 as the “Giacobinid” shower in honor of the comet Giacobini-Zinner,
which is associated with this particle-swarm.</p>
<div class="pb" id="Page_113">113</div>
<div class="img" id="fig40">
<img src="images/p38.jpg" alt="" width="800" height="598" />
<p class="pcap">Radiant of a meteor shower. Generally not a point but a small area,
here intentionally exaggerated in size. Solid arrows represent plotted
paths of observed meteors. By extending these paths backwards,
observer can determine the radiant.</p>
</div>
<div class="pb" id="Page_114">114</div>
<p>In the course of each year, the earth passes through a number
of particle-swarms of varying densities. Some of the resulting
meteor showers, like the Leonids and Giacobinids, are very feeble
in most years, but sometimes produce spectacular displays.</p>
<p>The more important recognized meteor showers are:</p>
<table class="center" summary="">
<tr><td class="l"><span class="sc">NAME OF SHOWER</span> </td><td class="l"><span class="sc">DATE OF MAXIMUM</span></td></tr>
<tr><td class="l">Quadrantids </td><td class="l">January 1-3</td></tr>
<tr><td class="l">Lyrids </td><td class="l">April 21</td></tr>
<tr><td class="l">Eta-Aquarids </td><td class="l">May 4-6</td></tr>
<tr><td class="l">Perseids </td><td class="l">August 10-14</td></tr>
<tr><td class="l">Giacobinids (Nu-Draconids) </td><td class="l">October 9</td></tr>
<tr><td class="l">Orionids </td><td class="l">October 20-23</td></tr>
<tr><td class="l">Leonids </td><td class="l">November 16-17</td></tr>
<tr><td class="l">Geminids </td><td class="l">December 12-13</td></tr>
</table>
<p>Certain daytime streams are also known to be active during June
and July. These daytime showers are, of course, invisible in the
glare of sunlight, but they can be picked up by radar devices like
those used in World War II to spot enemy airplanes.</p>
<p>Some meteor showers have been splendid enough to make a
place for themselves in the historical record. Examples are the
Leonid returns of 1833 and 1866, and the Giacobinid showers
of 1933 and 1946. During these displays, meteors fell in a veritable
fiery snowstorm, several hundred meteors sometimes appearing
within a minute.</p>
<p>Not every annual return of a meteor shower is spectacular,
<span class="pb" id="Page_115">115</span>
however, since conditions may not be favorable each year for a
brilliant display. After all, both parties to a traffic collision at an
intersection must try to pass through the intersection at the same
time. Our earth, like a well-managed train, always goes through
the intersection on schedule, but the particles responsible for
meteor showers are much more erratic. They may be early or
late—or they may not show up at all. Of the meteor showers seen
annually, the Perseids are the most dependable. The Leonids put
on their best shows at intervals of 33 years (1799-1800, 1832-33,
1866, etc.). The Giacobinids at intervals of 6½ years (1933,
strong; 1939-40, poor; 1946, magnificent).</p>
<p>If you plan to observe a meteor shower, here are some suggestions.
You will need:</p>
<blockquote>
<p>Acquaintance with the stars, both faint and bright, in the region
containing the radiant of the shower.</p>
<p>Comfortable reclining lawn-chair.</p>
<p>Warm clothing (including blankets) for winter showers or summer
ones at high elevations.</p>
<p>A patient family that will not only approve of your observing
but will help you get up to watch after midnight, when most
showers are at their best.</p>
<p>A corner of your back yard (or sun roof) where you can shade
your eyes from street lights and other illumination.</p>
<p>Timepiece, preferably with radiant dial.</p>
</blockquote>
<div class="pb" id="Page_116">116</div>
<p>Sit back and watch Nature put on her show. Any records you
make may have some scientific value even if you note only these
two things: Hourly number of meteors seen. Condition of the
sky (clear, hazy, cloudy, etc.) during each hour of your watch.<a class="fn" id="fr_6" href="#fn_6">[6]</a>
At present, we know of only one instance in which it seems
probable that a meteorite came to earth during a meteor shower.
The Mazapil, Mexico, iron meteorite fell at 9:00 p.m. on November
27, 1885, during a return of the now very weak Bielid
meteor shower. Scientists still cannot decide whether or not a
mere coincidence was involved in this case.</p>
<p>As we have already mentioned, most of the cosmic particles
rushing into our atmosphere evaporate and do not reach the
earth at all except as the tiny congealed droplets and spherules
of their own melt. Some cosmic particles, the <i>micro-meteorites</i>,
are so tiny that they “stall” rather than fall down. These minute
objects do not melt or disintegrate and so preserve their original
cosmic form unchanged. Scientists have developed various
methods for the collection of both of these types of material in
order that at least rough estimates of their rate of accumulation
on the earth can be made.</p>
<p>One of the simplest methods of collecting this so-called “meteoritic
dust” is to expose a sticky glycerine-coated glass microscope
slide for at least a 24-hour period in a protected spot well
<span class="pb" id="Page_117">117</span>
away from locations where any industrial contamination is in
the air. At the end of the period of exposure, the “catch” on the
slide is examined microscopically, and the individual trapped
particles are counted and classified. Meteoritic dust is also carried
down to the ground by rain, snow, and hail and can therefore
be obtained by filtering rainwater or melted glacier-ice,
snow, and hail.</p>
<p>Such collection efforts have been plagued by the difficulty of
identifying the particles. How can a collector be sure that the
dust he has trapped, even though magnetic and possibly even in
part metallic, does not come from some smelter or other industrial
plant? Because of such uncertainties, the current estimates
of the annual deposit of meteoritic dust for the world range from
approximately 20 tons to several million tons. We need improved
collection and identification techniques if we are to obtain trustworthy
figures.</p>
<p>Recent analyses of rainfall records indicate that the infall of
meteoritic dust produces at least one interesting weather-effect.
These analyses show that rainfall peaks often occur some 30
days after the appearance of important meteor showers. Apparently,
as meteoritic dust particles from the meteor showers filter
down through the cloud systems in the lower layers of the atmosphere,
the individual particles serve as centers about which
atmospheric moisture condenses to form raindrops. The time lag
of approximately a month is considered to be due to the very
slow rate of fall of such tiny particles. It looks very much as if
Mother Nature had beaten man to the idea of “seeding” the
clouds to produce rainfall!</p>
<div class="pb" id="Page_118">118</div>
<h2 id="c10"><span class="small">9. THE NATURE OF METEORITES</span></h2>
<p>So far in this book we have dealt with meteorites indirectly,
chiefly in connection with their fall, distribution, and recovery.
In this chapter, however, we are shifting our attention to the meteorites
themselves, and will tell what the main types of meteorites
are, what meteorites are made of, what they look like, and
how to tell them from ordinary rocks.</p>
<p>First of all, meteorites neither all look alike nor have the same
composition. The general term “meteorite” applies to any mass
that reaches the earth from space. Such masses are made up of
metals and minerals in varying proportions. The term “meteorite”
is nearly as general in meaning as the word “rock,” which
geologists apply to bodies, large and small, that are formed by
earth processes and are composed of various kinds of minerals.
Actually, there are almost as many different kinds of meteorites
as there are kinds of rocks; so you can see that in meteorites a
wide range of composition and appearance is possible.</p>
<p>All recognized meteorites belong to one of three main divisions,<a class="fn" id="fr_7" href="#fn_7">[7]</a>
<i>irons</i>, <i>stones</i>, and <i>stony-irons</i>.</p>
<p>The irons are composed of an alloy of iron and nickel which
may contain small inclusions of nonmetallic minerals.</p>
<div class="pb" id="Page_119">119</div>
<div class="img" id="fig41">
<img src="images/p39.jpg" alt="" width="800" height="674" />
<p class="pcap">Internal structure revealed when the “etching” process is applied to
that type of meteorite known as a “granular hexahedrite.” See
<a href="#Page_120">p. 120</a>.</p>
</div>
<div class="pb" id="Page_120">120</div>
<p>After a cut section of an iron meteorite has been polished, the
flat surface, except for possible inclusions, is mirror-like and resembles
stainless steel. It appears to be remarkably uniform and
uninteresting, but this appearance is misleading. A characteristic
and beautiful structural pattern develops when such a polished
nickel-iron surface is treated with, for example, a special
mixture of nitric acid, alcohol, and Arabol glue.</p>
<p>This process of treatment is known as “etching.” The different
structural patterns brought out by such etching give us the basis
for classifying the iron meteorites.</p>
<p>If the etching process reveals certain features from which we
can infer a cubic, or 6-faced, crystalline structure, we classify
the iron meteorite as a <i>hexahedrite</i>.</p>
<p>If etching produces a certain special pattern from which we
can infer an 8-faced, or octahedral, crystalline structure, we
recognize the second subdivision of iron meteorites: the <i>octahedrites</i>.
This remarkable pattern was discovered and first described
by Alois von Widmanstätten, of Vienna, in 1808.</p>
<p>The third subdivision of iron meteorites consists of the “structureless”
<i>ataxites</i>. (From the Greek for “without arrangement.”)
On an ataxite, etching brings out only a finely granular pattern
with a stippled appearance.</p>
<p>The <i>stones</i> are composed chiefly of minerals that are combinations
of various elements with silicon and oxygen—for example,
olivine (Mg, Fe)₂SiO₄. Meteorites belonging to this division
also contain combinations of elements with oxygen—such
as magnesium oxide (MgO) and aluminum oxide (Al₂O₃).
Usually, the stony groundmass contains scattered specks, grains,
and thin veins of the same shiny nickel-iron alloy that makes
up the iron meteorites almost in their entirety.</p>
<div class="pb" id="Page_121">121</div>
<div class="img" id="fig42">
<img src="images/p40.jpg" alt="" width="800" height="695" />
<p class="pcap"><span class="jr">A. BREZINA & E. COHEN PHOTO</span>
Widmanstätten pattern which emerges when the carefully polished
surface of that type of iron meteorite technically known as a “fine
octahedrite” is “etched.”</p>
</div>
<div class="pb" id="Page_122">122</div>
<p>The <i>stony-irons</i>, as the name indicates, are an “in-between”
division. Some of the stony-irons, called <i>pallasites</i>, are sponge-like
but rigid networks of nickel-iron alloy in which the smoothly
rounded openings in the sponge enclose small gemlike masses of
olivine. A cut and polished section of a pallasite showing round
and oval gems of yellow-green olivine set in a silvery mesh of
nickel-iron is a beautiful museum specimen indeed!</p>
<p>In the <i>silicate-siderites</i>, another type of stony-iron, a nickel-iron
matrix is studded with angular fragments, shreds, and
splinters of silicate minerals of all sizes. In the photograph, we
can see that each of the various areas of the nickel-iron matrix
(lighter in color) exhibits its own distinct crystallographic orientation,
as is clearly indicated by the different Widmanstätten
patterns.</p>
<p>Even a hasty comparison of polished sections of silicate-siderites
and pallasites will leave no doubt that two quite distinct
modes of formation were required to produce stony-irons of such
different types.</p>
<p>Meteoritic nickel-iron has the following average chemical
composition. To the nearest tenth, this alloy contains: Iron
(Fe), 90.9%; nickel (Ni), 8.5%; cobalt (Co), 0.6%. This
alloy gave scientists the key to the development of commercial
stainless steels. It may also contain small amounts of phosphorous,
sulfur, copper, chromium, and carbon.</p>
<p>The average chemical composition of stony meteoritic material
is somewhat more complicated. To the nearest tenth, the
“stones” contain: oxygen (O), 41.0%; silicon (Si), 21.0%;
iron (Fe), 15.5%; magnesium (Mg), 14.3%; aluminum (Al),
1.6%; calcium (Ca), 1.8%; sulfur (S), 1.8%. The stony material
may also contain smaller percentages of nickel, cobalt,
copper, carbon, chromium, and titanium.</p>
<div class="pb" id="Page_123">123</div>
<div class="img" id="fig43">
<img src="images/p41.jpg" alt="" width="794" height="361" />
<p class="pcap"><span class="jr">A. BREZINA & E. COHEN PHOTO</span>
Enlarged section of a stony-iron meteorite showing rounded
olivine grains (dark in color) set in a network of nickel-iron alloy
(light in color).</p>
</div>
<div class="img" id="fig44">
<img src="images/p41a.jpg" alt="" width="800" height="319" />
<p class="pcap"><span class="jr">A. BREZINA & E. COHEN PHOTO</span>
Polished and etched section of a silicate-siderite showing
angular fragments of silicate minerals (dark in color) imbedded in a
metallic matrix.</p>
</div>
<div class="pb" id="Page_124">124</div>
<p>In the stony-iron meteorites, we analyze the nickel-iron and
stony portions separately. On the average, each of these portions
has about the chemical composition that is given for it
above.</p>
<p>Mineralogists have identified a variety of familiar minerals
in meteorites. These include olivine, the plagioclase feldspars,
magnetite, quartz, chromite, and, rarely, microscopic diamonds.
All of these minerals are found here on earth in such igneous
rocks as basalts and peridotites.</p>
<p>On the other hand, the meteoritic nickel-iron alloys (kamacite,
taenite, and plessite, for example) and such meteoritic
minerals as schreibersite (nickel-iron phosphide) and daubreelite
(iron chromium sulfide) do <i>not</i> occur naturally on the
earth.</p>
<p>We should stress here that although unusual <i>combinations</i>
of known elements are present in meteorites, no new <i>elements</i>
have been discovered during the increasingly intensive study of
these masses during the last 150 years.</p>
<p>The majority of stony meteorites show a structure not found
in terrestrial rocks. These meteorites are made up of rounded,
shot-like bodies called <i>chondrules</i> (from the Greek word for
“grain”). The individual chondrules may vary in size from
those as large or even larger than a walnut down to dust-sized
grains. The most common size is about that of peppercorns. The
chondrules are often composed of the same material as the
groundmass in which they are imbedded and unless the meteorite
containing them is a very fragile one, they will break with
the rest of the mass, as will sand grains in a quartzite. If the
meteorite is fragile, however, the individual chondrules can
generally be broken out whole. Meteorites containing chondrules
are called <i>chondrites</i>.</p>
<div class="pb" id="Page_125">125</div>
<div class="img" id="fig45">
<img src="images/p42.jpg" alt="" width="800" height="696" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Microphotograph of a thin section of a chondrite, showing the circular,
or nearly circular, cross sections of a number of chondrules,
including one of large size at the upper edge of the section.</p>
</div>
<div class="pb" id="Page_126">126</div>
<p>A small percentage of stony meteorites have no chondrules.
These meteorites are known as <i>achondrites</i> (meaning “not
chondrites”) and they resemble terrestrial rocks more closely
than the chondrites do. Some achondrites contain almost
no trace whatever of metal, although in others (for example,
the Norton County meteorite, of <a href="#c3">Chapter 2</a>) small lumps and
specks of nickel-iron are sparsely distributed through the stony
groundmass.</p>
<p>Meteorites are as variable in shape as they are in composition
and structure. Many are cone-shaped; others shield-, bell-, or
ring-shaped; still others pear-shaped. One iron fragment recently
recovered from the Glorieta, New Mexico, fall has been
described as “macro-spicular,” meaning needle-shaped on a very
large scale. The photographs opposite illustrate a number of the
commoner forms known. The Glorieta specimen has been nicknamed
“Alley Oop’s shillelagh,” for only a person of great
strength could wield this 13-pounder with ease!</p>
<p>In general, the shape of meteorites depends upon the amount
of mass lost by “evaporation” during passage through the earth’s
atmosphere. This factor, in turn, depends not only upon the
speed of transit, but also on such physical characteristics of
the meteorite as its tensile strength and whether or not it contains
certain alloys and minerals that vaporize more easily than
the rest of the meteorite. The ring-shape of the Tucson, Arizona,
iron is believed to have resulted from the “melting away” of a
huge inclusion of stony material during the descent of the meteorite.</p>
<div class="pb" id="Page_127">127</div>
<div class="img" id="fig46">
<img src="images/p43.jpg" alt="" width="800" height="693" />
<p class="pcap"><span class="jr">CHICAGO MUSEUM OF NATURAL HISTORY PHOTOS</span>
<span class="jr">(BOTTOM RIGHT) INSTITUTE OF METEORITICS PHOTO</span>
A few of the many shapes exhibited by meteorites: ring-shaped,
perforated and highly irregular, pear-shaped, jaw shaped, needle-shaped.</p>
</div>
<div class="pb" id="Page_128">128</div>
<p>When meteorites are recovered and taken to the laboratory
for study, one of the first things scientists do is to weigh them.
If a meteorite is very large, special scales sometimes have to be
constructed for this purpose. Such was the case for the largest
meteorite so far weighed: the giant Ahnighito, Greenland, meteorite,
which Peary brought to New York City by ship. (See
<a href="#c4">Chapter 3</a>.) A specially constructed scale on which this huge
mass is now mounted gives for its weight about 68,000 pounds.
Other meteorites famous for their great size are: the Bacubirito,
Mexico, 27 tons; Willamette, Oregon, 14 tons; Morito, Mexico,
11 tons; and the Bendego, Brazil, 5 tons. All of these are irons.</p>
<p>The largest stone meteorite so far recovered as one mass is
the so-called Furnas County, Nebraska, stone, which is the principal
fragment of the Norton, Kansas, fall, and weighs about
2,360 pounds.</p>
<p>At the other end of the size-range, investigators have recovered
meteoritic masses weighing no more than a small fraction
of a gram. From a stone shower that occurred at Holbrook,
Arizona, field searchers have found some of the very smallest
specimens in anthills. The insects had carried these tiny meteorites
along with sand and garnet grains in building their
hills!</p>
<div class="pb" id="Page_129">129</div>
<div class="img" id="fig47">
<img src="images/p44.jpg" alt="" width="800" height="720" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
The Willamette iron, famous for its great size and weight (14 tons),
on exhibit at the Hayden Planetarium, New York City. See pp. <a href="#Page_36">36</a>,
<a href="#Page_39">39</a>.</p>
</div>
<div class="pb" id="Page_130">130</div>
<p>The only sure way to determine whether or not an object
<i>is</i> a meteorite is to have a small piece of it (say, a fragment
the size of an egg) tested chemically and microscopically by an
expert on meteorites. Nevertheless, there are several questions
whose answers will help you to decide whether or not you are
on the right track in suspecting that a “rock” you have found
may be a meteorite:</p>
<blockquote>
<p>Is your specimen especially heavy?</p>
<p>Does your specimen show a thin blackish or brownish
crust on its outer surface?</p>
<p>Does your “rock” have shallow, oval pits on its outer
surface?</p>
<p>If the specimen has a corner knocked off, do you see
specks and grains of metal on the broken surface?</p>
</blockquote>
<p>Is your specimen especially heavy? The iron and stony-iron
meteorites are very heavy. A 1-inch cube of iron meteorite
weighs approximately 8 times as much as a 1-inch cube of ice.
Even the stones, which are only about half as dense as the irons,
are much heavier than ordinary rocks.</p>
<p>Does your specimen show a thin blackish or brownish crust
on its outer surfaces? You will recall that specimens of both
the Ussuri and Norton meteorites showed a “glaze” of fused
material which we call fusion crust. Most freshly-fallen meteorites
are covered with such a crust. To illustrate how this crust
forms, consider a snowball that you bravely hold in your freezing
hand until the outer surface melts. If you then were to leave
the snowball outside overnight, the melted outer surface would
freeze into a hard crust.</p>
<div class="pb" id="Page_131">131</div>
<div class="img" id="fig48">
<img src="images/p45.jpg" alt="" width="800" height="580" />
<p class="pcap">Piezoglyphs (oval pits resembling thumb-prints) in a stone meteorite,
found at Belly River, Canada. See <a href="#Page_132">p. 132</a>.</p>
</div>
<div class="pb" id="Page_132">132</div>
<p>In similar fashion, the surface of a meteorite melts during
the blazing-hot part of its flight through the air, only to “freeze”
into a hard, firm coating in the lower, cooler portions of its
path. This hardened coating, the fusion crust, is of much importance.
Its presence is one of the best indications that a “rock”
is really a meteorite. From the character of the fusion crust,
experts can piece together a good deal about what happened
to a meteorite on its way down to earth. If you should be lucky
enough to find a meteorite, don’t break off the fusion crust. A
whole encrusted specimen in the hand is worth 200 crustless
fragments scattered at your feet!</p>
<p>Does your “rock” have shallow, oval pits or depressions on
its outer surface? Such features are known technically as <i>piezoglyphs</i>
(Greek <i>piezein</i>, to press + <i>glyph</i>, to carve) and popularly
as “thumb-prints.” They were formed during the meteorite’s
flight through the atmosphere when the softer portions of
its outer shell were “eroded” away, leaving small scooped-out
places. These pittings are very similar to the prints that would
be made by the human hand in a lump of modeling clay or
bread dough. In one case, they gave rise to the false idea that
the meteorite had fallen in a plastic state and that the imprints
had been formed when its finders first pulled the mass out of
the ground by hand.</p>
<p>If the specimen you have found already has a corner knocked
off, do you see specks and grains of metal on the broken surface?
Such scattered bits of nickel-iron (not to be confused with
<span class="pb" id="Page_133">133</span>
the shiny mica flakes often seen in igneous rocks) characteristically
occur in the grayish or brownish groundmass of stony
meteorites. If your specimen is unbroken, hold it lightly against
a spinning carborundum wheel or use a file to grind a small flat
surface upon it, and then examine this surface for specks of
metal.</p>
<p>If the answers to these questions are yes, then there is a good
possibility that you have found a genuine meteorite.</p>
<p>If meteorites remain buried in the ground for a long period
of time, their characteristic surface-features may weather away.
Under such conditions, iron meteorites develop heavy-layered
coatings of rust (iron oxide) as much as several inches in thickness.
If irons stay in the ground long enough, they may rust
away almost completely and turn into shale balls, like those
found near the ancient Wolf Creek, Australia meteorite crater.
(See <a href="#c5">Chapter 4</a>.) Stone meteorites buried in the ground for any
great length of time may disintegrate and become completely
unrecognizable as meteorites.</p>
<p>The fact that meteorites of all kinds are attacked by weathering
has always argued strongly in favor of their prompt recovery.
In the case of witnessed falls, prompt recovery is even more
important, for only thus can specimens still retaining measurable
amounts of various short-lived radioactivities be made available
to physicists eager to investigate them with the most modern
radiometric equipment.</p>
<div class="pb" id="Page_134">134</div>
<h2 id="c11"><span class="small">10. TEKTITES, IMPACTITES & “FOSSIL” METEORITES</span></h2>
<p>Before southern Australia was occupied by the white man, the
native tribesmen of that region treasured certain small rounded
pieces of black glass as medicine stones, rainmaking stones,
and message stones. The Wadikali tribe referred to these objects
as <i>mindjimindjilpara</i>, a word meaning “eyes that look at
you like a man staring hard.” The early European settlers of
the area called the same black glassy masses “blackfellows’
buttons.” Both phrases applied to objects that modern scientists
call “australites,” which are now one of the best known types of
<i>tektites</i> (Greek: <i>tēktos</i>, molten).</p>
<p>These Australian tektites and the tektites from many other
countries around the world are a problem to meteoriticists. The
question is, are they really meteorites? Many investigators believe
that the answer is yes, and they are inclined to add to the
three main divisions of true meteorites listed in the preceding
chapter, a fourth: the tektites.</p>
<p>These mysterious glassy objects occur in such widely separated
localities as Czechoslovakia, the Philippine Islands, Borneo,
the Ivory Coast of Africa, Australia, Indo-China, Texas,
Malaya, and Java. In these and still other areas, they have been
found by the thousands in surface deposits of sand, clay, and
gravel.</p>
<div class="pb" id="Page_135">135</div>
<div class="img" id="fig49">
<img src="images/p46.jpg" alt="" width="800" height="858" />
<p class="pcap">(left) “Flanged buttons” from Australia. (right) Several sizes of
“dumbbells” from Australia. See <a href="#Page_136">p. 136</a>.</p>
</div>
<div class="pb" id="Page_136">136</div>
<p>Tektites have never been seen to fall. In spite of this fact, as
we noted above, a number of scientists believe that, like the
meteorites, the tektites really did come from outer space but,
that they fell to earth before man was here to see them come
down—or at least before he had acquired the means and skill
to make lasting records of such an occurrence.</p>
<p>Tektites are usually quite small, weighing between 1 and 100
grams, although a few of much larger size have been found. One
large specimen from the Philippines weighed about ½ pound.
Two giant tektites, one weighing ¾ pound and the other
over 1 pound, are in the collection of the British Museum. In
composition, tektites are an impure silica-glass containing low
percentages of the oxides of such elements as iron, magnesium,
calcium, and titanium.</p>
<p>If tektite fragments are held under a lamp and observed by
reflected light, their thicker parts generally appear to be jet-black.
If, however, these same specimens are held up <i>between</i>
the observer and the light, then their thin razor-sharp edges are
seen to be bottle-green, yellow-green, brownish, or even colorless.</p>
<p>In shape, many tektites are roundish or oval. Others are
shaped like dumbbells, ladles, canoes, and teardrops. So they
are known by those descriptive terms. One particularly interesting
example is the unusual “flanged button” of Australia.
Tektites of this type look like miniature South American gold-pans,
the <i>bateas</i>, heaped high with pay dirt. Australian gold-field
workers regarded these tektites as magical, and used them as
good-luck charms. Superstitious American gold-seekers brought
them into the United States all the way from Australia!</p>
<div class="pb" id="Page_137">137</div>
<div class="img" id="fig50">
<img src="images/p47.jpg" alt="" width="800" height="849" />
<p class="pcap">(above) Rounded tektite from Texas. (below) Deeply grooved bediasite
from Texas.</p>
</div>
<div class="pb" id="Page_138">138</div>
<p>Some tektites (for example, many of the “bediasites” from
Texas) are deeply grooved and channeled, and have a very jagged
and irregular appearance. Even the smoother tektite surfaces
are characterized by flow lines, flow ridges, and bubble pits.</p>
<p>Many weathered pebbles and fragments of obsidian somewhat
resemble the tektites superficially. There is a very simple
test by which you can distinguish true tektites from obsidian.
If you hold a thin splinter of tektite glass in a blowpipe flame,
the glass melts quietly but only with the greatest difficulty. On
the contrary, when you test in the same flame the terrestrial
glass, obsidian, it froths up much more easily, into a bubbly,
whitish mass.</p>
<p>Although the question of where the tektites came from is still
not entirely settled, most scientists agree that all tektites did
have a <i>common</i> origin. For example, tektites from widely scattered
localities on the earth’s surface show not only similar queer
shapes and surface markings (technically known as “sculpturing”),
but also have very much the same chemical composition
and, in particular, the same content of radioactive elements.</p>
<p>Because the tektites chemically resemble certain terrestrial
rocks, scientists at first believed that some kind of earth process
must have created them. One suggestion was that lightning had
fused dust particles suspended in the air to form them; another,
that they had come from volcanoes; still another, that the tektites
were simply inclusions that had weathered out of terrestrial
rocks. A few scientists once took seriously the possibility
that tektites were refuse from primitive glass factories!</p>
<div class="pb" id="Page_139">139</div>
<div class="img" id="fig51">
<img src="images/p48.jpg" alt="" width="800" height="468" />
<p class="pcap">Tektite vs. obsidian, after blowpipe test.</p>
</div>
<div class="pb" id="Page_140">140</div>
<p>While such theories have not yet been completely discarded,
most scientists now feel that the tektites had their origin somewhere
outside the earth. There are several reasons for this
belief. First, the shape of such unusually symmetrical forms as
are found, for example, among the australites, indicates that
these small bodies at one time were members of a swarm of
freely-spinning liquid masses. Again, flow features observed on
the surfaces of certain tektites (and the fusion crust definitely
identified on one specimen) show that these bodies at some time
must have traveled through the earth’s atmosphere at high velocity.</p>
<p>If, then, the tektites were not produced by earth processes,
where did they come from? According to primitive legends, they
were “rocks” or “pebbles” from the moon. Indeed, one of the
earliest scientific theories as to their origin (proposed by the
Dutch authority Verbeek in 1897) likewise attributes them to
debris jetted out from the moon. Another holds that tektites are
fragments of the outermost glassy layers of some so-called “meteorite-planet,”
or planets.<a class="fn" id="fr_8" href="#fn_8">[8]</a> Still another idea is that tektites are
what is left of a comet when it passes so close to the blazing-hot
sun that the “ices” which make up most of the cometary nucleus
(head) are all distilled away.</p>
<p>These theories of the origin of the tektites are based primarily
on their observed shapes, surface features, and compositions.
The senior author of this book has suggested still another
possible theory based on the very unusual nature of the observed
distribution of the tektites on the face of the earth.</p>
<p>To explain this theory, we first recall that the planet on which
we live is more nearly a true sphere than are such familiar
<span class="pb" id="Page_141">141</span>
“spherical” objects as baseballs or basketballs. Consequently,
any plane through the center of the earth cuts its surface in a
curve that to all intents and purposes is what geometers refer
to as a <i>great circle</i>.</p>
<div class="img" id="fig52">
<img src="images/p49.jpg" alt="" width="800" height="400" />
<p class="pcap">Every plane passing through the center of a sphere intersects the
surface in a great circle. In this figure, only the front half of the
great circle cut out by the plane is shown.</p>
</div>
<p>Now the significant fact is that all the tektite deposits known
at present are located on or very near to three great circles on
the earth’s surface. Mathematics shows that if some earth process
had created the tektites at random over the surface of the
<span class="pb" id="Page_142">142</span>
earth, then the odds would be very strongly against the existence
of this peculiar “great-circle distribution.” But such distribution
along great circles would be <i>expected</i> if the tektites had
resulted from what might be likened to “chain-falls” upon the
earth of objects like nearby satellites moving in orbits encircling
our globe.</p>
<p>This notion brings up the interesting possibility that at some
time in the remote past, the earth may have been the proud
possessor of a set of equatorial rings. These rings would have
been similar to those at present circling in the plane of Saturn’s
equator. (Jupiter, too, may once have had its own set of equatorial
rings.) The rings of Saturn are known to be made up of
countless very small meteorites. In the same way, the “earth
rings” of prehistory could have consisted of swarms of tiny
nearby meteoritic satellites—the tektites—moving about the
earth in the plane of its then-existing equator.</p>
<p>Eventually, the innermost of these small natural satellites collapsed
onto the earth’s surface, falling along the old equator. At
least twice thereafter, this process was repeated, the points of
impact of the later tektite falls again lining up along whatever
great circle of the earth happened to be the equator at the time
of fall.</p>
<p>As the geologists and other investigators have shown, major
shifts have occurred in the position of the earth’s equator during
past geologic ages. This fact is well-substantiated by discoveries
of fossil shells and plants on the cold Antarctic continent
and of glacial deposits in hot South Africa. Therefore, we
could hardly expect the tektite deposits, which are believed to
<span class="pb" id="Page_143">143</span>
have fallen at widely separated intervals of time, to have all
occurred along a <i>single</i> great circle on the earth’s surface.</p>
<p>As you can see, the so-called “tektite-puzzle” is a complex
one. As if this were not bad enough, Mother Nature has added
to the confusion by creating in addition to the tektites another
type of silica-glass not only found along the very same three
great circles sprinkled with true tektites, but also having other
features in common with the tektite glasses.</p>
<p>At Mount Darwin in Tasmania and at Wabar in the Rub’ al
Khali desert of Arabia, large and small fragments of this curious
silica-glass have been collected. At Wabar the masses of
silica-glass were found in and about the rims of a series of meteorite
craters formed in nearly pure sand, as we pointed out in
<a href="#c5">Chapter 4</a>. These meteorite craters are known to have resulted
from the high-speed impact of iron meteorites upon the sand
dunes of the Wabar site. Since the silica-glasses of Wabar have
been found to contain countless spherules of nickel-iron of the
same composition as the iron meteorites discovered about the
Wabar meteorite craters, it seems quite certain that both the
sand of the earth target and the nickel-iron of the falling meteorites
were vaporized by the intense heat generated at impact.
Consequently, it is natural that these Wabar masses of congealed
silica-glass and nickel-iron be called <i>impactites</i>. They are silica-glasses,
created chiefly from <i>terrestrial</i> materials by the impact
of large crater-forming meteorites. This same name is
now applied to all silica-glasses believed to have the same origin
as those at Wabar.</p>
<p>As regards size if not composition, the crater-forming meteorites
<span class="pb" id="Page_144">144</span>
responsible for the Wabar and other impactites may have
been big brothers of the small-fry responsible for the showers
of true tektites. Or these big ones may have moved about the
earth in orbits distinct from those followed by the tektite swarms
but lying in the same plane as one of these swarms.</p>
<p>In addition to the curious puzzle of the tektites, meteoriticists
have also run up against the problem of “fossil” meteorites or,
more exactly, the problem of the <i>lack</i> of “fossil” meteorites. As
we have already mentioned, no positively identified meteorite
has ever been found in other than the most recent rock layers.
With all the mining—particularly coal mining—that has gone
on throughout the world in historic times, this fact does seem
astonishing.</p>
<p>A number of explanations can be suggested for this absence
of ancient meteorites. In the geologic past, meteorite falls may
not have occurred as often as they do today. For example, the
primeval atmosphere of the earth may have been so much denser
than at present that even quite large meteorites were totally
vaporized as they passed through it and therefore never reached
the ground. Again, even if the rate of infall of meteorites was
the same in the remote past as now, still various weathering
processes active ever since the earliest meteorites fell may have
so changed them in appearance and composition that they are
no longer recognizable for what they are.</p>
<p>Several unusual lumps of rock from England and a mass
of iron from Austria, all found at some depth by coal miners,
have been tentatively put forward as “fossil” meteorites. But
studies of these masses have so far produced no conclusive results.
Still, we should not ignore the possibility that someday
meteorites may be found and identified in rocks of considerable
age.</p>
<div class="pb" id="Page_145">145</div>
<div class="img" id="fig53">
<img src="images/p50.jpg" alt="" width="800" height="572" />
<p class="pcap"><span class="jr">L. J. SPENCER PHOTO</span>
<span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Mysterious glass objects found in the Libyan Desert. (right) Cut and
polished specimens.</p>
</div>
<div class="pb" id="Page_146">146</div>
<p>Does it seem as if we have posed more problems than we have
solved in this chapter? It is very true that we have done just that.
In speaking briefly about the tektites, the impactites, and the
absence of “fossil” meteorites, we have by no means tried to present
the last word on the troublesome but highly interesting
problems connected with these objects—problems that admittedly
may take scientists years or even decades of further research
to solve. Perhaps you will find here the kind of unusual
and thought-provoking problems that make the study of meteorites
a rather special challenge. If so, you may wish to take
an active part someday in unraveling these puzzles.</p>
<div class="pb" id="Page_147">147</div>
<h2 id="c12"><span class="small">11. OMENS AND FANTASIES</span></h2>
<p>Men seem to have always taken an interest in meteorites, but
not until the early nineteenth century were these objects considered
to be worth preserving for <i>scientific</i> study.</p>
<p>In the beginning, people believed that because meteorites fell
from the heavens, they were either gods themselves or messengers
from the gods. The more civilized of early men therefore
carefully kept the fallen meteorites. They draped them in costly
linens and anointed them with oil. In many instances, the people
built special temples in which meteorites were actually worshipped.
Some of the holy stones of the ancients, such as the
Diana of the Ephesians, mentioned in the Bible as “the image
which fell down from Jupiter,”<a class="fn" id="fr_9" href="#fn_9">[9]</a> are now thought to have been
meteorites.</p>
<p>Meteorite worship was common long ago in the Mediterranean
area and in Africa, India, Japan, and Mexico. This practice
still persists in some regions even in modern times. The
Black Stone of the Kaaba, for example, has been sacred to all
Mohammedans from about 700 <span class="sc">A.D.</span> right up to the present. It
is said to be a meteorite although this fact has never been verified,
because strict religious taboos connected with the stone
prevent any scientific examination or study of it. On the contrary,
the Andhâra, India, meteorite is known to be a genuine
one. The story of the fall and preservation of this meteorite provides
a fairly modern example of practices rooted in the ritual
and custom of far more ancient times.</p>
<div class="pb" id="Page_148">148</div>
<p>At about 4:00 in the afternoon of December 2, 1880, the
people of Andhâra heard a noise like that made by a gun. Some
of the villagers saw a “dark ball” come to earth in a field near
them. This falling object sent up a small cloud of dust as it
struck the ground. After the stone had been recovered from the
field and the dust had been washed from its surface, two Brahmin
priests took charge of it and began to collect money for
the erection of a temple in which the holy object could be
properly displayed.</p>
<p>The scientist who promptly investigated the Andhâra fall reported
that throngs of worshippers were crowding into the as
yet unfinished brick temple to make offerings of flowers, sweetmeats,
milk, rice, water, bel leaves, and of course money. The
stone had been named Adbhuta-Nâth, “the miraculous god.” It
was shaped like a round loaf of blackish bread and weighed an
estimated 6 pounds. The scientist was not allowed to touch it,
but he got close enough to verify that the stone was a meteorite
covered with a typical blackish fusion crust.</p>
<p>Not only has man worshipped meteorites, but during a period
extending from approximately 300 <span class="sc">B.C.</span> to 300 <span class="sc">A.D.</span>, emperors
and self-governing cities frequently marked the fall of meteorites
by minting special coins or medals known as <i>betyls</i>.<a class="fn" id="fr_10" href="#fn_10">[10]</a> One of
these is the betyl of Emisa, Syria, made by Antonius Pius (138-161
<span class="sc">A.D.</span>). The historian, Herodotus, accurately described the
object honored by this betyl as: “A large stone, which on the
lower side is round, and above runs gradually to a point. It has
nearly the form of a cone, and is of a black color. <i>People say of
it in earnest that it fell from Heaven.</i>” The stone is shown on the
coin as carried on a quadriga (a carriage drawn by four horses)
under a canopy of four sunshades.</p>
<div class="pb" id="Page_149">149</div>
<div class="img" id="fig54">
<img src="images/p51.jpg" alt="" width="800" height="579" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Drawing of multiple fireball, over Athens, October 18, 1863. J. F. J.
Schmidt, the celebrated pioneer fireball observer, described it as a
mass of dazzling light “bringing into view land and sea, with the
Acropolis and the Parthenon a mile away across the city.”</p>
</div>
<div class="pb" id="Page_150">150</div>
<p>Many ancient peoples held meteorites in great reverence,
particularly if they were seen to fall. But at the same time, other
more practical-minded individuals made good use of the durable
and easily worked alloy provided by nature in the nickel-iron
meteorites. This alloy was frequently used to make ax-heads,
spear and harpoon points, knives, farming tools, stirrups
and spurs, and even pots and other utensils. Archeologists have
found earrings and similar ornaments overlaid with thin sheets
of hammered meteoritic iron in Indian mounds of the Ohio Valley.
They have also discovered round beads made of nickel-iron
in Indian mounds of the Havana, Illinois, area and in the still
more ancient Egyptian ruins at Gerzah.</p>
<p>Meteoritic iron has often been used in the manufacture of
special swords, daggers, and knives for members of the royalty.
Atilla and other early conquerors of Europe boasted of “swords
from heaven.” Emperor Jehangir (1605-1627) ordered two
sword blades, a knife, and a dagger to be smelted from the Jalandhar,
India, meteorite, which fell on April 10, 1621. In the
early nineteenth century, a sword was manufactured from a
portion of the Cape of Good Hope meteorite for presentation to
Alexander, the Emperor of Russia. Even as late as the end of the
nineteenth century, several swords were made from a part of the
Shirihagi, Japan, iron meteorite at the command of a member of
the Japanese court.</p>
<div class="pb" id="Page_151">151</div>
<div class="img" id="fig55">
<img src="images/p52.jpg" alt="" width="800" height="563" />
<p class="pcap">A Russian artist’s pen-and-ink drawing of an extremely brilliant
detonating fire ball or bolide. See <a href="#Page_102">page 102</a>.</p>
</div>
<div class="pb" id="Page_152">152</div>
<p>In the Europe of the Middle Ages, meteorite falls and meteor
showers, as well as other “unnatural” events like comets, eclipses,
and displays of the aurora borealis, were regarded with superstitious
awe by commoner and king alike. The medieval mind always
sought to interpret events connected in any way with the
heavens as somehow influencing the affairs of men. A bishop
explained that the great meteor shower of April 4, 1095, forecast
“the changes and wanderings of nations from kingdom to kingdom.”
The fact, however, that the First Crusade began within a
year, is mere coincidence.</p>
<p>In referring to celestial events, Shakespeare often expressed
the view that was common in the Middle Ages and the Renaissance.
An example is:</p>
<div class="verse">
<p class="t0">The bay-trees in our country are all wither’d</p>
<p class="t0">And meteors fright the fixed stars of heaven;</p>
<p class="t0">The pale-faced moon looks bloody on the earth</p>
<p class="t0">And lean-look’d prophets whisper fearful change,</p>
<p class="lc"><span class="gs">. . . . . .</span></p>
<p class="t0">These signs forerun the death or fall of kings.</p>
<p class="lr">(<i>Richard II</i>, II, iv, 8-11, 15)</p>
</div>
<p>Yet the descent of meteorites from the heavens was not always
regarded as a forewarning of bad fortune. On November
16, 1492, a 279-pound meteorite fell at Ensisheim in Alsace,
not far from the battle line separating the armies of France and
the Holy Roman Empire. Emperor Maximilian, the leader of
the Empire’s forces, commanded that the fallen stone be carried
to his castle. There a formal war-council was held to determine
what the strange event could mean.</p>
<div class="pb" id="Page_153">153</div>
<div class="img" id="fig56">
<img src="images/p53.jpg" alt="" width="800" height="586" />
<p class="pcap"><span class="jr">COURTESY OF AMERICAN MUSEUM OF NATURAL HISTORY</span>
Drawing of Andromedid meteor shower, November 27, 1872.</p>
</div>
<div class="pb" id="Page_154">154</div>
<p>The Emperor and his councillors decided that the fall of the
meteorite at such a time and place was an omen of divine favor
which meant good fortune to the cause of the Holy Roman
Empire. After breaking off two small pieces of the stone, one
for the Duke of Austria and one for himself, the Emperor forbade
further damage to it. He also gave orders that the stone
be hung in the parish church in Ensisheim for all to see. In
this way, the Ensisheim stone became the very first meteorite
of witnessed fall to be preserved down to the present day—and
all because of the superstition of a famous military leader.</p>
<p>The discussion to this point makes clear that in ancient, medieval,
and Renaissance times, meteorite falls were considered
as startling and disturbing events, which frequently were interpreted
in strange and mistaken ways. But the fact that meteorites
actually did fall from the heavens was not questioned.
As the so-called “Age of Reason” opened, a curious change in
attitude toward meteorite falls took place.</p>
<p>At the very time that knowledge in general increased, men
of learning began to deny that meteorite falls occurred at all!
The scientists of the French Academy, in particular, were very
positive on this point. Since the era was one in which all Europe
sneezed if “la belle France” had a cold in the head, it was a
trying time not only for the early meteoriticists, but for all who
had the nerve to insist they had seen rocks fall from the sky.</p>
<p>By the end of the 1700’s, the authorities had studied the evidence
relating to meteorite falls and had completely rejected
it. They said that there was no “proof” whatever that “stones
fell from the heavens.” These early scientists openly sneered at
people who claimed that they had seen meteorites fall. It was
felt that the spectators of such events either had merely been
<span class="pb" id="Page_155">155</span>
“seeing things,” or had surely been reporting light and sound
effects connected with nothing but ordinary thunderstorms.</p>
<p>When confronted with the “fallen” masses themselves, the
authorities often refused to examine them, or if they did, insisted
that these masses were only rocks that had been struck
by lightning. Such were the opinions of learned men around the
close of the eighteenth century.</p>
<p>Fortunately, scientific facts have a stubborn way of winning
out in the long run. A major part of the credit for seeing that
the truth regarding meteorite falls was at last recognized must
go to E. F. F. Chladni, a German physicist, and to Edward
Howard, an English chemist.</p>
<p>In 1794, Chladni published an extremely important paper
concerning a large spongelike mass of “native iron” found near
Krasnoyarsk, Russia. This object had been discovered in 1749
by a Russian blacksmith, and it was studied in 1772 by P. S.
Pallas, an early traveler. Chladni concluded that the mass of
iron<a class="fn" id="fr_11" href="#fn_11">[11]</a> must have fallen from the heavens, because it had been
“fused” (but not by man, electricity, or fire) and also because
there were no volcanoes anywhere around its place of find.</p>
<p>Chladni supported his theory by listing numerous reports of
meteorite falls dating from ancient and medieval times. But
Chladni’s fellow scientists flatly rejected his theory as clever
but not satisfactory.</p>
<p>With the fall of the Siena meteorites in Italy on June 16, 1794,
<span class="pb" id="Page_156">156</span>
the controversy regarding the possibility that stones actually
fell from the sky became particularly heated, and remained so
for nearly ten years. During this interval, two other important
meteorite falls occurred: Wold Cottage, England, on December
13, 1795, and Benares, India, on December 19, 1798. Scientists
had a hard time finding explanations for these well-observed
events, and some of the theories put forward to account
for them far outdid Chladni’s in “cleverness,” if that be the
correct word.</p>
<p>One scholar, writing in 1796, suggested that the masses
which fell at Siena resulted from the solidification at great
height of volcanic ashes from Mount Vesuvius. These ashes had
supposedly been carried northward beyond Siena and then been
“brought back by a northerly wind, congealing from the air....”</p>
<p>Fortunately, in 1803 Edward Howard’s chemical work on
meteorites came to a successful conclusion. This patient chemist
made analyses of samples from the Siena, Wold Cottage, and
Benares falls and from an older Bohemian fall. He also had the
samples studied mineralogically by a fellow scientist. From the
results of these investigations, he drew the following conclusions,
which admirably supported Chladni’s well-reasoned and
thoroughly documented theory regarding meteorite falls:</p>
<blockquote>
<p>All four of the stones studied had very nearly the same composition.</p>
<p>Despite the fact that the stones contained no new elements, their
mineralogical character differed in several important respects
from that of any rocks found naturally on the earth.</p>
<div class="pb" id="Page_157">157</div>
<p>The four masses must have had a common origin although their
reported falls had been widely separated both in time and in
space.</p>
<p>Finally, said Howard, it was quite possible that the stones had
really fallen from the sky.</p>
</blockquote>
<p>Howard’s views were soon put to the test. Shortly after the
publication of his important paper, a shower of stony meteorites
fell near L’Aigle, France, on April 26, 1803. This event was
carefully investigated by French scientists, and they reluctantly
admitted that about 3,000 stones actually had fallen within an
oval-shaped area about 6 miles long by 2 miles wide. This
shower of meteorites had been accompanied by the same light
and sound effects mentioned in many of the old meteorite-fall
reports collected by Chladni, effects now recognized as characteristic
of the infall of meteorites upon the earth. The evidence
was overwhelming—stones really did fall from the sky. In the
camp of the enemy, so to speak, the reality of meteorite falls
was established once and for all!</p>
<div class="pb" id="Page_158">158</div>
<h2 id="c13"><span class="small">12. THE MODERN VIEW</span></h2>
<p>After the L’Aigle shower of 1803, a whole new era opened
in the study of meteorites. No longer did scientists hold these
objects up to ridicule and scorn. Instead, they came to regard
meteorites as well worth collection and careful study.</p>
<p>The Vienna Museum, the British Museum, the Paris Museum,
the Academy of Science of St. Petersburg (now Leningrad),
and the U.S. National Museum began to build up splendid
meteorite collections. Scientists in Germany, England,
France, and Russia engaged in the painstaking mineralogical
study and classification of individual meteorite specimens.</p>
<p>The modern science of meteoritics is rooted deep in the nineteenth
century. Many special fields of investigation had their
beginnings then. Scientists became interested in the chemistry,
the mineralogy, and the metallurgy of meteorites; in the orbits
of meteorites and the trajectories they follow through the earth’s
atmosphere down to impact with the ground; and in the distribution
of meteorite falls in space and time.</p>
<p>From this period we can date such milestones of progress
in meteoritics as:</p>
<blockquote>
<p>The discovery of the beautiful and significant Widmanstätten
patterns characteristic of the majority of the irons, and the less
spectacular but equally important lines named for J. G. Neumann,
the German meteoriticist who discovered them, in 1848,
in the Braunau meteorite.</p>
<p>The realization that there were many different kinds of meteorites
<span class="pb" id="Page_159">159</span>
and that these diverse objects were very important to an
understanding of the internal structure and origin of the earth,
and perhaps of the Solar System and the wider cosmos as well.</p>
<p>Tentative explanations of the violent and terrifying light and
sound effects connected with meteorite falls.</p>
<p>Tentative explanations of such oval-shaped areas as shown above.</p>
</blockquote>
<div class="img" id="fig57">
<img src="images/p54.jpg" alt="" width="800" height="462" />
<p class="pcap">Typical distribution of meteorite fragments according to size, within
oval-shaped area of fall. The larger masses of the shower carry
farther on, in the direction of the motion of the meteorite. As early
as 1814, investigators had noted this peculiarity of meteorite-shower
distributions. See pp. <a href="#Page_32">32</a>, <a href="#Page_89">89</a>, <a href="#Page_94">94</a>.</p>
</div>
<div class="pb" id="Page_160">160</div>
<p>By 1850, A. Boisse, an early French geologist and meteoriticist,
had put forth the basic <i>meteorite-planet</i> hypothesis. According
to this theory of his, meteorites are the fragments of a planet<a class="fn" id="fr_12" href="#fn_12">[12]</a>
that formerly orbited between Mars and Jupiter in what is now
called the “asteroid belt.” And untold millions of years ago,
this planet was shattered by some unknown but very great force,
possibly collision with another celestial body.</p>
<p>The structure of the meteorite-planet was considered to have
been very much like that of the earth. The various divisions of
recognized meteorites were believed to be representatives of
the several concentric, or nested, shells of material originally
making up the destroyed planet. These shells were progressively
less dense with increasing distance from the center of the planet.</p>
<p>Today Boisse’s theory is one of the most widely accepted as
an explanation of at least one major category of the meteorites.
Some modern investigators would insist that the meteorite-planet
had a thin outer glassy shell from which the tektites came.</p>
<p>Most of the larger fragments of the meteorite-planet, now
called the <i>asteroids</i>, move so that the average asteroidal orbit
very closely approximates the orbit of the original planet. But
many of the smaller fragments follow paths in space that differ
considerably from the original meteorite-planet’s orbit. Even
some of the asteroids behave this way, either because of the high
speeds they acquired at the time of disruption of the meteorite-planet,
or because of the later influence of the major planets and
particularly of the giant planet, Jupiter.</p>
<div class="pb" id="Page_161">161</div>
<div class="img" id="fig58">
<img src="images/p55.jpg" alt="" width="800" height="409" />
<p class="pcap">A diagram (not drawn to scale) showing position of asteroid-belt
with respect to the orbits of Mars and Jupiter. The asteroids with
average orbits move within this belt. The non-typical asteroid indicated
follows an orbit that brings it well inside that of the earth.
There are a number of asteroids with such peculiar orbits. It is possible
that in the past a nickel-iron asteroid in one of these orbits collided
with the earth and produced the Canyon Diablo meteorite
crater.</p>
</div>
<div class="pb" id="Page_162">162</div>
<p>In fact, at the present time, several asteroids move well within
the orbits of the earth and Venus. It is quite possible therefore
that such a large meteorite crater as the one at Canyon Diablo,
was produced by the prehistoric fall of one of these small members
of our Solar System. If so, we have reason to believe that
a core-fragment of the meteorite-planet came to earth at Canyon
Diablo. For the extensive mining operations carried out
there during the last half-century have shown that the projectile
responsible for this greatest of all meteoritic shell-holes in
the face of Mother Earth was a mass of solid nickel-iron, which
in all likelihood was core material.</p>
<p>The lengthy and costly series of mining operations at Canyon
Diablo were all undertaken in the hope of locating the “main
mass” of this huge projectile and thus of opening up what might
be called a cosmic-lode of quite valuable metals. Unfortunately,
the miners overlooked the fact that impacts at meteoritic
speeds produced almost incredible amounts of heat. Even the
solid iron meteorites are vaporized and widely dispersed at the
temperatures resulting from such impacts, as we have seen was
the case at Wabar (see <a href="#c5">Chapter 4</a>). So it was at Canyon Diablo.</p>
<p>The idea of a cosmic-metal mine might at first strike some
readers as too futuristic to take seriously. But the necessity for
catching a core-fragment before it enters the consuming atmosphere
of our planet is really nothing new. As far back as 1939,
the senior author had occasion to point out that if we wish to start
a successful cosmic-metal mine, we must catch our core-fragment
before it is turned into unminable vapor. This point will
come up again in the <a href="#c11">next chapter</a>.</p>
<div class="pb" id="Page_163">163</div>
<div class="img" id="fig59">
<img src="images/p56.jpg" alt="" width="436" height="401" />
<p class="pcap">Cross-section of Boisse’s hypothetical meteorite-planet. Fragmentation
of this sphere was believed to have given rise to the following
divisions of meteorites:</p>
<p class="pcap">The <i>iron</i> meteorites came from <b>A</b>, the dense nickel-iron core.</p>
<p class="pcap">The stony-iron meteorites came from <b>B</b>, the intermediate zone of
cellular nickel-iron and silicate minerals.</p>
<p class="pcap">The <i>stony</i> meteorites came from <b>C</b>, the outer zone of silicate minerals
in which relatively little or no nickel-iron is present. The
chondrites were believed to come from the inner portion of this
zone; the achondrites, from the outer portion.</p>
</div>
<div class="pb" id="Page_164">164</div>
<p>There are several other theories of the origin of meteorites
interesting enough to mention. The early view that the meteorites
were debris thrown out by ancient volcanoes on the moon
or recent ones on the earth came to be discredited largely on
physical grounds. On the other hand, extremely violent <i>primordial</i>
volcanoes on the earth (not the weak ones of historic
times, like Aetna or Vesuvius) could have ejected material that
in much later times fell, and continues to fall back on our globe.
This theory has not been ruled out and it still receives support,
for example, from some authorities in the U.S.S.R. These same
Russian scientists take most seriously a suggestion that the meteorites
(and comets as well) were thrown out by volcanoes
believed to exist on the planet, Jupiter—a theory dating back
almost a century to the English astronomer, R. A. Proctor.</p>
<p>Some scientists believe that meteorites represent the congealed
remains of gaseous bolts of matter ejected by the sun.
Others interpret them as fragments of comets that have been
torn apart by passing too close to the sun, which is the most
powerful gravitational center in the Solar System.</p>
<p>Chemists, geologists, astronomers, and physicists—as well
as the meteoriticists themselves—are constantly working toward
a solution of the problem of the meteorites. Where do these
bodies come from? What can we learn from them about their
age and origin and about the age and origin of our Solar System?
Years may be required, but eventually the riddle of the
meteorites will be solved by the patient, concerted efforts of
men and women of science.</p>
<div class="pb" id="Page_165">165</div>
<div class="img" id="fig60">
<img src="images/p57.jpg" alt="" width="800" height="740" />
<p class="pcap">Collapsed mine buildings in the bottom of the Canyon Diablo meteorite
crater. A shaft was put down here in one of several unsuccessful
attempts to locate the main mass of the meteorite. See pp.
<a href="#Page_44">44</a>-52.</p>
</div>
<div class="pb" id="Page_166">166</div>
<h2 id="c14"><span class="small">13. PRESENT AND FUTURE APPLICATIONS</span></h2>
<p>So far we have considered what might be called the “pure”
rather than the “applied” side of the study of meteorites. The
investigator in any pure science asks of a new discovery, “What
does this tell me about the universe? How does it better help
me to understand the laws of nature?” Of the same discovery,
however, the worker in an applied science will ask, “What practical
use can be made of this gain in knowledge? What can it
be made to do for mankind in general?”</p>
<p>These questions reveal a decided difference in viewpoint,
but this difference does not reflect unfavorably on either class
of scientists. In fact, there is a great deal of truth in the saying
“Today’s pure science is tomorrow’s applied.” Actually, ways
and means of taking advantage of seemingly useless scientific
discoveries are constantly being found. The most famous example
of this principle is the development of the atomic bomb
from the results of Einstein’s researches in the abstract field
of relativity. Here the seemingly mystic formula E = mc² came
to have far-reaching practical applications indeed!</p>
<p>Meteoritics has some exceedingly practical applications. Far
from being completely “out of this world”—as the recovered
meteorites themselves originally were—this science has been
and can be made to serve mankind in a number of rather unexpected
ways. Meteoritics, the onetime “stepchild of astronomy,”
is currently being regarded with ever-increasing respect
<span class="pb" id="Page_167">167</span>
by scientists and engineers working in many different fields.</p>
<p>Consider, first of all, the stainless steels that are so widely
used in modern industry, and even the fine satin-sheen stainless
“silverware” that graces our dining tables. These have
wisely been patterned after a natural alloy with lasting qualities
of strength, tenacity, and resistance to corrosion. This natural
alloy is the one making up the iron meteorites.</p>
<p>Its toughness and durability became well known wherever
attempts were made to section these metallic meteorites. Specially
designed and extra-powerful sawing equipment is required
to slice meteoritic iron, and even with it, progress is
painfully slow. So astounded were those who first tried to cut
iron meteorites with ordinary metal saws that one of the earliest
practical results was the development of battleship armor plate
composed of a commercial alloy called “meteor steel,” which
mimicked the composition of the iron meteorites.</p>
<p>Of course, a good deal of the difficulty of sectioning meteorites
arises from the fact that those doing the cutting are trying
hard not to waste valuable meteoritic material. Every precaution
is taken to keep the amount of “sawdust” to a minimum,
for such finely ground up and contaminated meteoritic material
is of little scientific use. And, in addition, scientists must guard
against heating meteorites to high temperatures because such
heating destroys the delicate internal structure of the masses.
If these two considerations (loss of material and overheating)
were unimportant, even a large meteorite could easily be divided
up by use of such high-powered oxyacetylene torches as
are used to dissect huge obsolete battleships.</p>
<div class="pb" id="Page_168">168</div>
<p>At the Institute of Meteoritics, a thin, water-cooled blade of
soft iron is driven slowly back and forth by an electric motor.
Carborundum grit in water suspension is fed evenly into the
narrow cut over its entire length. This grit becomes imbedded
in the lower edge of the soft iron blade, which then acts as a
“many-toothed” metal saw. Several meteorites can be sectioned
simultaneously by this multiblade saw. In the future, such newly
developed methods as high-speed particle jet streams or ultrasonic
devices may be used to section meteorites both rapidly and
economically.</p>
<p>In the field of cosmic ray studies, particularly those concerned
with the protection of space travelers from harmful
radiation, meteoritics can be of help. The recovered meteorites
have already come through those regions that would be crossed
by even the farthest-ranging spaceships. Consequently, a great
deal can be learned from the study of meteorites about the
intensity of the cosmic radiation that the crews of such ships
must face once they get outside the earth’s protective air-shield.</p>
<p>The first study of this type was made in May, 1948, at the
Institute for Nuclear Studies of the University of Chicago (now
the Enrico Fermi Institute). Scientists made radioactivity tests
on samples of the Norton County meteorite donated for this
purpose by the Institute of Meteoritics and air-expressed to
Chicago because of the intense interest in the radioactivity
question. In October, 1949, English investigators ran similar
tests at the Londonderry Laboratory for Radiochemistry, Durham,
England, on samples of the freshly fallen Beddgelert,
North Wales, meteorite discussed on pp. <a href="#Page_69">69</a>-70. The results of
these two pioneer studies were negative because the “Model-T”
instruments available in 1948 and 1949 were not sensitive
enough to detect the relatively low radioactivities present.</p>
<div class="pb" id="Page_169">169</div>
<div class="img" id="fig61">
<img src="images/p58.jpg" alt="" width="800" height="620" />
<p class="pcap">The 6-blade meteorite gang-saw in the machine shop at the Institute
of Meteoritics.</p>
</div>
<div class="pb" id="Page_170">170</div>
<p>In 1955, however, scientists at Purdue University, using more
refined counters, studied small nuggets of nickel-iron, also from
the Norton meteorite. This time, the results of the radioactivity
tests were positive. The investigators detected tritium (an isotope
of hydrogen produced by cosmic-ray bombardment) in
the samples. Furthermore, the <i>amount</i> of this rare isotope present
indicated that the intensity of cosmic radiation outside the
earth’s atmosphere may be very much higher than had previously
been thought possible. “Forewarned is forearmed,” and
from the standpoint of future astronauts, this is as practical a
result as one could wish for!</p>
<p>In the relatively near future, men will certainly land on the
surface of the moon. We know from radiometric studies that
some degree of radioactivity is induced in meteorites by the
full-intensity cosmic radiation to which they have been exposed
during their motion through space. The nearly airless moon,
like the meteorites, has also been exposed to very intense cosmic
radiation for a long time. So those who are planning to land on
our satellite are concerned about the radioactivities they will
encounter when they begin their explorations of the lunar
surface.</p>
<p>Suppose that extra-sensitive instruments were designed to
pick up and measure the radioactivities. Suppose further that
these instruments were mounted in a space-probe put in an orbit
circling closely about the moon. Plans for such a project are
<span class="pb" id="Page_171">171</span>
now under way. What types and intensities of lunar radioactivities
might such probe-mounted instruments record?</p>
<p>Until such a space-probe becomes available, earth-bound
space-scientists are seeking at least a preliminary answer to
this question. They are doing this by investigating the natural
“probes” that have come to us from space—the meteorites.</p>
<p>Investigators have undertaken such studies very recently
by employing a new radiometric method technically called
<i>gamma-ray spectroscopy</i>. Work of this sort has been and is
being done at the Los Alamos, New Mexico, Scientific Laboratory
on scores of meteorite and tektite specimens loaned to the
Laboratory by the Institute of Meteoritics. Some of the individual
meteorite specimens tested weighed as much as 37 pounds,
and are probably the largest single extra-terrestrial masses yet
tested for cosmic ray-induced radioactivities.</p>
<p>Let us turn now to another important application of meteoritics.
Any body in motion through the air or in space has a
“striking power” of sorts. For some objects, this striking power,
which is technically known as <i>ballistic potential</i>, is very weak,
as in the case of silky milkweed-down drifting through the air.
Hailstones have a good deal more striking power, as may have
been painfully demonstrated on your own head. And, finally,
such masses as falling meteorites (and especially those orbiting
in space, unretarded by atmospheric resistance) have an extraordinarily
formidable ballistic potential. This is because meteorites
are not only tough and dense, as good projectiles must be,
but are also moving at high velocities—particularly high if the
meteorites come into the Solar System from interstellar space.</p>
<div class="pb" id="Page_172">172</div>
<p>For this reason, the speeds of meteorites are very important
to scientists responsible for rocket flights and for keeping satellites
aloft over long periods of time. Clearly, these men must
have as accurate information as possible on where and how
fast meteoritic particles are moving, so as to chart the safest
routes for spaceships, and to develop satisfactory means of protecting
rockets and satellites against the effects of bombardment
by the smaller meteorites. For these “small-fry” cosmic
missiles are so numerous that many of them are sure to be encountered
even in brief flights outside the earth’s atmosphere.</p>
<p>Such information might also prove valuable in the future
to the crews of spaceships on long flights into deep space. Such
men may face the life or death problem of taking successful
“evasive action” against giant meteorites that will seem like
flying hills and mountains.</p>
<p>A strong parallelism exists between a meteorite fall and the
re-entry of a nose-cone or data-capsule into the atmosphere.
To a considerable extent, the difficult problems connected with
the latter are being attacked at present through careful studies
of meteorites. From the air-sculptured shapes of meteorites,
their crustal flow patterns, and the thicknesses and types of fusion
crusts they show, scientists are learning a great deal about
certain factors connected with the re-entry problem. These factors
include rate of vaporization, effects of extreme temperatures,
and types of sculpturing to be expected as a result of encountering
the resisting molecules of the atmosphere.</p>
<div class="pb" id="Page_173">173</div>
<div class="img" id="fig62">
<img src="images/p59.jpg" alt="" width="800" height="669" />
<p class="pcap">Relationship between (<b>A</b>) the trajectory of a falling meteorite, and
(<b>B</b>) the re-entry stage of a V-2 rocket. The solid lines indicate the
similar portions of the two trajectories.</p>
<dl class="undent pcap"><dt><b>A.</b> <span class="small">A METEORITE FALL</span></dt>
<dt><b>B.</b> <span class="small">A V-2 RE-ENTRY</span></dt></dl>
</div>
<div class="pb" id="Page_174">174</div>
<p>One of the most obvious applications of meteoritics in the
future will grow out of the well-known fact that our earthly
resources of many strategic materials—especially metals like
iron and nickel—are fast becoming exhausted. The population
of the earth is increasing at a mad pace, and an end to metal-consuming
wars is still not in sight. The need for such metals
can only become more and more acute.</p>
<p>According to one of the currently favored explanations of
the origin of the meteorites, the core-fragments of the parent
meteorite-planet are solid masses of nickel-iron alloy—like the
mass that blasted out the Canyon Diablo meteorite crater. If
this meteorite-planet hypothesis finally wins general acceptance,
the meteoriticist of the future is almost sure to be set the
task of pin-pointing as exactly as possible the whereabouts in
space and time of the most easily accessible cosmic nickel-iron
lodes of this sort. Once he has given an answer, the space engineers
will take over, and mining operations will be started on
the unlimited sources of essential metals to be found in outer
space.</p>
<p>Initially, no doubt, metal recoveries will be freighted back
to earth in rocket-load lots. But as the need for iron and nickel
increases on a metal-hungry earth, vast engineering projects
may well be undertaken to “snare” the larger metal meteorites
and equip them with rocket motors. This will be done so that
by use of rocket power, the natural orbits of the meteorites can
be changed into orbits bringing them back to earth. Unlike the
natural, uncontrolled Canyon Diablo meteorite fall that vaporized
what would have been a rich nickel-iron deposit, the
rocket-controlled meteoritic “metal mines” will be eased down
to earth all in one piece.</p>
<div class="pb" id="Page_175">175</div>
<p>Reading of the possibility of sending out expeditions to find
large iron meteorites in the depths of space may bring to your
mind an image of the fearless mariners of old who sailed their
stout ships over dangerous, often uncharted seas in search of
the great whales. The rocket crews of day-after-tomorrow will
no doubt be equally fearless and resourceful as they navigate
the sea of space, intent on capturing the great “metal mines”
of the future.</p>
<p>The experience gained in such space-mining ventures will
then be carried over into expeditions to ensnare the larger
stony-iron meteorites. These masses of iron and stone will offer
less favorable mining possibilities, but they can be turned into
rocket-propelled and guided de luxe space-cruisers. By this
term, we do not mean that these natural space-ships will house
all the luxuries of the ocean-liners advertised in the travel magazines.
Rather, we see them as providing roomy, comfortable
“underground” living quarters. Furthermore, their occupants
will be adequately protected by great thicknesses of metal and
rock from the injurious radiations of empty space, and the meteorites
that make the term “empty space” something of a misnomer.</p>
<p>Initially, such worlds-in-miniature will be much sought after
as laboratory sites where the more violent and dangerous of
the many experimental tests which venturesome man will wish
to conduct can be carried on without danger to the close-packed
billions populating the then-crowded earth.</p>
<p>Later on, these meteorites-turned-into-space-ships may be
used to explore the dangerous and faraway corners of the Solar
<span class="pb" id="Page_176">176</span>
System, since the very substance of each massive meteoritic
rocket-body will serve as an adequate and handy source of fuel
supply.</p>
<p>When men have learned to live on such “homes away from
home,” it is quite possible that the larger of these modified
meteorites, after their interiors have been opened up for occupancy
by the inroads of the fuel-hungry rocket-motors, may
be steered into neighborly orbits about old Mother Earth. Here,
these “natural” satellites will assume the unexciting but necessary
roles of the extra living quarters that by then will be so
urgently needed to accommodate the mushrooming population
of the world of the future.</p>
<p>People who live in these super-urban outliers of Mother
Earth may take the same pride in their natural, if converted,
homes as many former city dwellers now take in the old-fashioned
sprawling farmhouses they have rebuilt and occupied.
Perhaps one of your descendants will live in such a meteorite-orb,
and occasionally point the finger of scorn at the more
elegant but unpleasantly overcrowded artificial satellites preferred
by those migrants from teeming earth who lack the true
pioneering instinct. Who knows!</p>
<div class="pb" id="Page_177">177</div>
<h2 id="c15"><span class="small">FOR FURTHER READING</span></h2>
<p>If you are especially interested in meteoritics, you already may
have read some good books on general astronomy. There are many
and most of them are not too advanced for the beginner. Unfortunately,
these books devote but little space to meteoritics, the “Johnny-come-lately”
of astronomy. Almost all of the writings on meteors and
meteorites you will find largely profitable to read are in professional
meteoritical publications. A selected list of such publications, containing
much or at least a worthwhile amount of material you will now be
able to understand, is given below. Your chief difficulty in using this
list will be in finding some of the more important items in the holdings
of your public library, unless it is a large and well-stocked one. Your
librarian, however, may be able to help you get the item from some
other library—perhaps from that of a nearby university or college.</p>
<h4>METEORIC ASTRONOMY</h4>
<p>MEBANE, A. D. “The Canadian Fireball Procession of 1913,
February 9,” <i>Meteoritics</i>, Vol. 1, No. 4 (1956), pp. 405-421. Eyewitness
accounts of the most famous fireball procession on record.</p>
<p>OLIVIER, C. P. <i>Meteors</i>, Williams and Wilkins, Baltimore, 1925.
An exhaustive survey of work done by visual meteor-observers.</p>
<p>SCHIAPARELLI, G. V. <i>Shooting Stars</i>, a translation by C. C.
Wylie and J. R. Naiden, published in the <i>Proceedings, Iowa Academy
of Science</i>, Vol. 50 (1943), pp. 48-153. A pioneer treatise, dated 1867,
which is basic to later work in this field.</p>
<p>WHIPPLE, F. L. “Photographic Meteor Studies, I,” <i>Proceedings,
American Philosophical Society</i>, Vol. 79, No. 4 (1938), pp. 499-548.
Fundamental paper on the subject. Of the six meteors analyzed,
five followed elliptical orbits and one, a strongly hyperbolic orbit.</p>
<div class="pb" id="Page_178">178</div>
<h4>METEORITES</h4>
<p>FARRINGTON, O. C. “A Catalogue of the Meteorites of North
America to January 1, 1909,” <i>Memoirs, National Academy of Sciences</i>,
Vol. 13 (1915). Contains fascinating accounts of the phenomena
connected with meteorite falls, interspersed with lengthy technical
chemical and microscopic studies of meteorites.</p>
<p>FARRINGTON, O. C. <i>Meteorites</i> [published by the author],
Chicago, 1915. The classic American work on meteorites. The first
half of the book is popular; the last half is technical.</p>
<p>HEY, M. H. and PRIOR, G. T. <i>Catalogue of Meteorites</i>, William
Clowes & Sons, London, 1953. An exhaustive catalog of all recognized
and also, unfortunately, of many doubtful meteorite falls and
finds, from the beginning of the historical record up to December
1952.</p>
<p>LAPAZ, LINCOLN. “The Achondritic Shower of February 18,
1948,” <i>Publications, Astronomical Society of the Pacific</i>, Vol. 61
(1949), pp. 63-73.</p>
<p>LAPAZ, LINCOLN. “The Effects of Meteorites upon the
Earth,” <i>Advances in Geophysics</i>, Vol. 4, edited by H. E. Landsberg,
Academic Press, New York, 1958, pp. 217-350. A monograph covering
such topics as meteorite hits upon buildings and people, meteorite
detectors, and the nature and age of meteorite craters.</p>
<p>LEONARD, F. C. “The Furnas County, Kansas, Achondritic Fall
(1000,400),” <i>Contributions, Meteoritical Society</i>, Vol. 4 (1948), pp.
138-141. This paper and the eighth item, above, discuss the phenomena
of the fall of the largest aerolite so far recovered anywhere in the
world.</p>
<p>MERRILL, G. P. “The Story of Meteorites,” <i>Minerals from Earth
and Sky</i>, Vol. 3, Part I, Smithsonian Scientific Series, 1929, pp. 1-163.
A chiefly popular survey of the subject by a master meteoriticist.</p>
<div class="pb" id="Page_179">179</div>
<p>PERRY, S. H. <i>The Metallography of Meteoric</i> [meteoritic] <i>Iron</i>,
U. S. National Museum Bulletin No. 184 (1944). A summary of
knowledge on the subject, supplemented by exceptionally fine photographs
of etched meteorite sections.</p>
<p>SWINDEL, G. W., JR., and JONES, WALTER B. “The
Sylacauga, Talladega County, Alabama, Aerolite: A Recent Meteoritic
Fall that Injured a Human Being,” <i>Meteoritics</i>, Vol. 1, No. 2
(1954), pp. 125-132.</p>
<p>WHITE, C. S. and BENSON, OTIS O. (editors) <i>Physics and
Medicine of the Upper Atmosphere</i>, University of New Mexico Press,
Albuquerque, 1952. See Chapter X, “Meteoritic Phenomena and Meteorites,”
by F. L. Whipple, pp. 137-170; and Chapter XIX, “Meteoroids,
Meteorites, and Hyperbolic Meteoritic Velocities,” by Lincoln
LaPaz, pp. 352-393. Modern views on the meteorite velocity
controversy.</p>
<h4>METEORITE CRATERS</h4>
<p>LAPAZ, LINCOLN. “The Craters on the Moon,” <i>Scientific
American</i>, Vol. 181, No. 4 (1949), pp. 2-3. A popular exposition of
the Bénard-Wasiutynski theory of the origin of the ordinary (nonrayed)
craters on the moon.</p>
<p>SPENCER, L. J. “Meteorite Craters as Topographical Features on
the Earth’s Surface,” <i>Geographical Journal</i>, Vol. 81 (1933), pp. 227-248.
The classic paper on terrestrial meteorite craters.</p>
<h4>METEORITIC DUST</h4>
<p>BUDDHUE, J. D. <i>Meteoritic Dust</i>, The University of New Mexico
Press, Albuquerque, 1950. An account of the various techniques
used in collecting and studying meteoritic dust; and also of the conclusions
drawn from the study of such dust.</p>
<div class="pb" id="Page_181">181</div>
<h2 id="c16"><span class="small">INDEX</span></h2>
<p class="center"><a href="#index_A" class="ab">A</a> <a href="#index_B" class="ab">B</a> <a href="#index_C" class="ab">C</a> <a href="#index_D" class="ab">D</a> <a href="#index_E" class="ab">E</a> <a href="#index_F" class="ab">F</a> <a href="#index_G" class="ab">G</a> <a href="#index_H" class="ab">H</a> <a href="#index_I" class="ab">I</a> <a href="#index_J" class="ab">J</a> <a href="#index_K" class="ab">K</a> <a href="#index_L" class="ab">L</a> <a href="#index_M" class="ab">M</a> <a href="#index_N" class="ab">N</a> <a href="#index_O" class="ab">O</a> <a href="#index_P" class="ab">P</a> <a href="#index_Q" class="ab">Q</a> <a href="#index_R" class="ab">R</a> <a href="#index_S" class="ab">S</a> <a href="#index_T" class="ab">T</a> <a href="#index_U" class="ab">U</a> <a href="#index_V" class="ab">V</a> <a href="#index_W" class="ab">W</a> <span class="ab">X</span> <a href="#index_Y" class="ab">Y</a> <a href="#index_Z" class="ab">Z</a></p>
<dl class="index">
<dt class="center" id="index_A"><b>A</b></dt>
<dt>achondrites, <a href="#Page_126">126</a>, <a href="#Page_163">163</a>, <a href="#Page_178">178</a></dt>
<dt>Adelie Land stone, <a href="#Page_78">78</a></dt>
<dt>Adrar iron, <a href="#Page_38">38</a>, <a href="#Page_40">40</a></dt>
<dt>aerolites, <a href="#Page_178">178</a>, <a href="#Page_179">179</a></dt>
<dd><i>see also</i>, <a href="#index_StonesMeteoritic" class="ab">stones, meteoritic</a></dd>
<dt>age of meteorites and/or craters, <a href="#Page_50">50</a>, <a href="#Page_52">52</a></dt>
<dt>Aggie Creek iron, <a href="#Page_76">76</a></dt>
<dt>Ahnighito iron, <a href="#Page_36">36</a>, <a href="#Page_128">128</a></dt>
<dt>Algoma meteorite, <a href="#Page_75">75</a></dt>
<dt>“Alley Oop’s shillelagh,” <a href="#Page_126">126</a></dt>
<dt><a id="index_Altitude">altitude</a>, <a href="#Page_88">88</a>, <a href="#Page_90">90</a>, <a href="#Page_105">105</a>, <a href="#Page_106">106</a></dt>
<dt>American Meteor Society, <a href="#Page_116">116</a></dt>
<dt>American Museum of Natural History, <a href="#Page_37">37</a></dt>
<dt>Anderson Township meteorites, <a href="#Page_76">76</a></dt>
<dt>Andhâra stone, <a href="#Page_147">147</a>-8</dt>
<dt>Andromeda, Great Spiral Nebula in, <a href="#Page_2">2</a></dt>
<dt>Andromedid shower, <a href="#Page_153">153</a></dt>
<dt>anthills, meteorites in, <a href="#Page_128">128</a></dt>
<dt>anti-matter, <a href="#Page_58">58</a>-60</dt>
<dt>Aouelloul crater, <a href="#Page_65">65</a></dt>
<dt>appearance and disappearance of meteors, <a href="#Page_86">86</a>, <a href="#Page_94">94</a>, <a href="#Page_106">106</a></dt>
<dt>applied science, <a href="#Page_166">166</a></dt>
<dt>archeologists, <a href="#Page_76">76</a>, <a href="#Page_150">150</a></dt>
<dt>areas of fall, <a href="#Page_13">13</a>-4, <a href="#Page_24">24</a>, <a href="#Page_26">26</a>, <a href="#Page_32">32</a>, <a href="#Page_89">89</a>, <a href="#Page_94">94</a>, <a href="#Page_159">159</a></dt>
<dt>armor plate, <a href="#Page_167">167</a></dt>
<dt>asteroid belt and orbits, <a href="#Page_160">160</a>-1</dt>
<dt>astronautics, <a href="#Page_110">110</a>, <a href="#Page_168">168</a>, <a href="#Page_170">170</a>-6</dt>
<dt>ataxites, <a href="#Page_120">120</a></dt>
<dt>Athens, multiple fireball over, <a href="#Page_149">149</a></dt>
<dt>australites, <a href="#Page_134">134</a>, <a href="#Page_140">140</a></dt>
<dt>azimuth, astronomical, <a href="#Page_88">88</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_B"><b>B</b></dt>
<dt>Bacubirito iron, <a href="#Page_128">128</a></dt>
<dt>Bald Eagle iron, <a href="#Page_76">76</a></dt>
<dt>ballistic potential, <a href="#Page_171">171</a></dt>
<dt>Baxter stone, <a href="#Page_73">73</a></dt>
<dt>Bear Lodge iron, <a href="#Page_76">76</a></dt>
<dt>Beddgelert stone, <a href="#Page_69">69</a>-70, <a href="#Page_73">73</a>, <a href="#Page_168">168</a></dt>
<dt>bediasites, <a href="#Page_136">136</a>, <a href="#Page_137">137</a></dt>
<dt>Belly River stone, <a href="#Page_131">131</a></dt>
<dt>Benares meteorite, <a href="#Page_156">156</a></dt>
<dt>Bendego iron, <a href="#Page_128">128</a></dt>
<dt>Benld stone, <a href="#Page_73">73</a></dt>
<dt>Benson, O. O., <a href="#Page_179">179</a></dt>
<dt>Bethlehem stone, <a href="#Page_73">73</a></dt>
<dt>betyls, <a href="#Page_148">148</a>, <a href="#Page_150">150</a></dt>
<dt>Bible, meteorite mentioned in, <a href="#Page_147">147</a></dt>
<dt>Bielid shower, <a href="#Page_116">116</a></dt>
<dt>“blackfellows’ buttons,” <a href="#Page_134">134</a></dt>
<dt>Black Stone of the Kaaba, <a href="#Page_147">147</a></dt>
<dt>Boisse, A., <a href="#Page_160">160</a>, <a href="#Page_163">163</a></dt>
<dt>bolides, <a href="#Page_102">102</a>, <a href="#Page_151">151</a></dt>
<dt>Braunau iron, <a href="#Page_73">73</a></dt>
<dt>Brenham craters and meteorites, <a href="#Page_52">52</a>, <a href="#Page_65">65</a>, <a href="#Page_66">66</a>, <a href="#Page_78">78</a></dt>
<dt>Box Hole Station crater, <a href="#Page_65">65</a></dt>
<dt>Bridgewater meteorite, <a href="#Page_75">75</a></dt>
<dt>British Museum, <a href="#Page_136">136</a>, <a href="#Page_158">158</a></dt>
<dt>Buddhue, J. D., <a href="#Page_179">179</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_C"><b>C</b></dt>
<dt>Campo del Cielo craters, <a href="#Page_50">50</a>, <a href="#Page_65">65</a></dt>
<dt>Canyon Diablo crater, <a href="#Page_44">44</a>-52, <a href="#Page_65">65</a>, <a href="#Page_66">66</a>, <a href="#Page_75">75</a>, <a href="#Page_96">96</a>, <a href="#Page_161">161</a>, <a href="#Page_162">162</a>, <a href="#Page_165">165</a>, <a href="#Page_174">174</a></dt>
<dt>Cape of Good Hope iron, <a href="#Page_150">150</a></dt>
<dt>Cape York iron, <a href="#Page_36">36</a>, <a href="#Page_37">37</a></dt>
<dt>Carlton meteorite, <a href="#Page_75">75</a></dt>
<dt>Casas Grandes iron, <a href="#Page_76">76</a></dt>
<dt>charms, meteorites used as, <a href="#Page_134">134</a>, <a href="#Page_136">136</a></dt>
<dt class="pb" id="Page_182">182</dt>
<dd><i>see also</i> <a href="#index_SacredMeteorites" class="ab">sacred meteorites</a>; <a href="#index_Superstitions" class="ab">superstitions</a></dd>
<dt>Chesterfield meteorite, <a href="#Page_75">75</a></dt>
<dt>Chladni, E. F. F., <a href="#Page_155">155</a>-7</dt>
<dt>chondrules and chondrites, <a href="#Page_124">124</a>-6, <a href="#Page_163">163</a></dt>
<dt>Chubb crater, <a href="#Page_52">52</a>-4</dt>
<dt>coins depicting meteorites, <a href="#Page_148">148</a>, <a href="#Page_150">150</a></dt>
<dt>collection of meteorites in institutions, <a href="#Page_20">20</a>, <a href="#Page_32">32</a>, <a href="#Page_34">34</a>, <a href="#Page_37">37</a>, <a href="#Page_38">38</a>, <a href="#Page_40">40</a>-1, <a href="#Page_90">90</a>, <a href="#Page_136">136</a>, <a href="#Page_158">158</a></dt>
<dt>comets, <a href="#Page_114">114</a>, <a href="#Page_140">140</a>, <a href="#Page_164">164</a></dt>
<dt>composition of meteor-forming particles, <a href="#Page_160">160</a>-7</dt>
<dt>composition of meteorites, <a href="#Page_118">118</a>-26, <a href="#Page_163">163</a>, <a href="#Page_179">179</a></dt>
<dt>composition of tektites, <a href="#Page_136">136</a>-8</dt>
<dt>Constantia stone, <a href="#Page_74">74</a></dt>
<dt>contraterrene matter, <a href="#Page_56">56</a>, <a href="#Page_58">58</a>-60</dt>
<dt>convection-current hypothesis, <a href="#Page_63">63</a>-4</dt>
<dt>cosmic metal mine, <a href="#Page_162">162</a>, <a href="#Page_174">174</a>-6</dt>
<dt>cosmic rays, <a href="#Page_168">168</a>-71</dt>
<dt>craters, <a href="#Page_17">17</a>, <a href="#Page_18">18</a>, <a href="#Page_20">20</a>, <a href="#Page_42">42</a>-65, <a href="#Page_66">66</a>, <a href="#Page_96">96</a>, <a href="#Page_143">143</a>, <a href="#Page_178">178</a>, <a href="#Page_179">179</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_D"><b>D</b></dt>
<dt>Dalgaranga crater, <a href="#Page_65">65</a></dt>
<dt>daubreelite, <a href="#Page_124">124</a></dt>
<dt>destruction by meteorites, <a href="#Page_11">11</a>, <a href="#Page_15">15</a>, <a href="#Page_16">16</a>-19, <a href="#Page_54">54</a>-7, <a href="#Page_68">68</a>-70, <a href="#Page_73">73</a>-4, <a href="#Page_178">178</a></dt>
<dt>diamond-bearing meteorite, <a href="#Page_82">82</a></dt>
<dt>direction measures, <a href="#Page_23">23</a>, <a href="#Page_24">24</a>, <a href="#Page_86">86</a>-9, <a href="#Page_110">110</a></dt>
<dt>distribution of meteorites, <a href="#Page_66">66</a>-68, <a href="#Page_72">72</a>, <a href="#Page_140">140</a>-3, <a href="#Page_159">159</a></dt>
<dt>dog and meteorite, <a href="#Page_73">73</a></dt>
<dt>doubters of meteorites, <a href="#Page_154">154</a>-7</dt>
<dt>“dumbbells,” <a href="#Page_135">135</a>, <a href="#Page_136">136</a></dt>
<dt>“dust balls,” <a href="#Page_106">106</a></dt>
<dt><a id="index_DustMeteoritic">dust, meteoritic</a>, <a href="#Page_102">102</a>, <a href="#Page_116">116</a>-7, <a href="#Page_179">179</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_E"><b>E</b></dt>
<dt>“earth-rings,” <a href="#Page_142">142</a></dt>
<dt><a id="index_EarthTrace">earth-trace</a>, <a href="#Page_92">92</a></dt>
<dt>eating a meteorite, <a href="#Page_82">82</a></dt>
<dt>Einstein, A., <a href="#Page_166">166</a></dt>
<dt>elements in meteorites, <a href="#Page_118">118</a>-24</dt>
<dt>elements in meteor-forming particles, <a href="#Page_107">107</a></dt>
<dt>elevation, apparent, <a href="#Page_88">88</a>, <a href="#Page_90">90</a></dt>
<dd><i>see also</i> <a href="#index_Altitude" class="ab">altitude</a></dd>
<dt>“end-point,” <a href="#Page_16">16</a>, <a href="#Page_86">86</a>-91</dt>
<dt>Enrico Fermi Institute, <a href="#Page_168">168</a></dt>
<dt>Ensisheim stone, <a href="#Page_152">152</a>, <a href="#Page_154">154</a></dt>
<dt>Eta-Aquarid shower, <a href="#Page_114">114</a></dt>
<dt>etching meteorites, <a href="#Page_119">119</a>-123</dt>
<dt>evaporation, <i>see</i> <a href="#index_Vaporization" class="ab">vaporization</a></dt>
<dt>“explosions” of meteors and/or meteorites, <a href="#Page_18">18</a>, <a href="#Page_23">23</a>, <a href="#Page_25">25</a>, <a href="#Page_55">55</a>, <a href="#Page_56">56</a>-60, <a href="#Page_63">63</a>, <a href="#Page_86">86</a>, <a href="#Page_92">92</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_F"><b>F</b></dt>
<dt>fall, determining area of, <a href="#Page_13">13</a>-14, <a href="#Page_24">24</a>, <a href="#Page_26">26</a></dt>
<dd><i>see also</i> <a href="#index_OvalShapedAreasOfFall" class="ab">oval-shaped areas of fall</a></dd>
<dt>falls, witnessed, <a href="#Page_11">11</a>-22, <a href="#Page_23">23</a>-34, <a href="#Page_67">67</a>, <a href="#Page_68">68</a>-72, <a href="#Page_82">82</a>, <a href="#Page_84">84</a>-95</dt>
<dt>Farrington, O. C., <a href="#Page_178">178</a></dt>
<dt>farmers as meteorite finders, <a href="#Page_28">28</a>, <a href="#Page_30">30</a>, <a href="#Page_75">75</a>-6</dt>
<dt>Fermi (Enrico) Institute, <a href="#Page_168">168</a></dt>
<dt>fireballs, <a href="#Page_2">2</a>, <a href="#Page_10">10</a>, <a href="#Page_11">11</a>-13, <a href="#Page_23">23</a>-5, <a href="#Page_54">54</a>, <a href="#Page_69">69</a>, <a href="#Page_84">84</a>-92, <a href="#Page_102">102</a>, <a href="#Page_106">106</a>, <a href="#Page_149">149</a>, <a href="#Page_151">151</a></dt>
<dt>fishermen net meteorite, <a href="#Page_78">78</a></dt>
<dt>fixes, <a href="#Page_84">84</a>-90</dt>
<dt>“flanged buttons,” <a href="#Page_135">135</a>, <a href="#Page_136">136</a></dt>
<dt>flight-path, <i>see</i> <a href="#index_Trajectory" class="ab">trajectory</a></dt>
<dt>Flows meteorite, <a href="#Page_82">82</a></dt>
<dt>footwarmer, meteorite used as, <a href="#Page_78">78</a></dt>
<dt>“fossil” meteorites, <a href="#Page_144">144</a>-6</dt>
<dt class="pb" id="Page_183">183</dt>
<dt>funnels, impact and penetration, <a href="#Page_20">20</a>, <a href="#Page_29">29</a>, <a href="#Page_32">32</a>, <a href="#Page_33">33</a>, <a href="#Page_42">42</a>, <a href="#Page_44">44</a></dt>
<dt>Furnas County stone, <a href="#Page_29">29</a>, <a href="#Page_31">31</a>, <a href="#Page_32">32</a>-4, <a href="#Page_128">128</a>, <a href="#Page_178">178</a></dt>
<dd><i>see also</i> <a href="#index_NortonCountyFall" class="ab">Norton County fall</a></dd>
<dt>fusion crust, <a href="#Page_20">20</a>, <a href="#Page_21">21</a>, <a href="#Page_130">130</a>, <a href="#Page_132">132</a>, <a href="#Page_140">140</a>, <a href="#Page_148">148</a>, <a href="#Page_172">172</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_G"><b>G</b></dt>
<dt>Galle, J. G., <a href="#Page_92">92</a></dt>
<dt>gamma-ray spectroscopy, <a href="#Page_171">171</a></dt>
<dt>Geminid shower, <a href="#Page_114">114</a></dt>
<dt>Giacobinid shower, <a href="#Page_103">103</a>, <a href="#Page_114">114</a>, <a href="#Page_115">115</a></dt>
<dt>Giacobini-Zinner comet, <a href="#Page_114">114</a></dt>
<dt><a id="index_Glass">glass</a>, <a href="#Page_138">138</a>, <a href="#Page_145">145</a></dt>
<dd><i>see also</i> <a href="#index_SilicaGlass" class="ab">silica-glass</a>; <a href="#index_Tektites" class="ab">tektites</a></dd>
<dt>Glorieta iron, <a href="#Page_126">126</a></dt>
<dt>great-circle distributions, <a href="#Page_140">140</a>-3</dt>
</dl>
<dl class="index">
<dt class="center" id="index_H"><b>H</b></dt>
<dt>Harvard meteor-photographs, <a href="#Page_110">110</a>-1</dt>
<dt>Haviland craters, <a href="#Page_50">50</a>, <a href="#Page_52">52</a>, <a href="#Page_65">65</a>, <a href="#Page_66">66</a></dt>
<dt>Hayden Planetarium, <a href="#Page_129">129</a></dt>
<dt>height, <a href="#Page_88">88</a>, <a href="#Page_90">90</a>, <a href="#Page_105">105</a>, <a href="#Page_106">106</a></dt>
<dt>Henbury craters, <a href="#Page_50">50</a>, <a href="#Page_65">65</a></dt>
<dt>Hey, M. H., <a href="#Page_178">178</a></dt>
<dt>hexahedrites, <a href="#Page_119">119</a>, <a href="#Page_120">120</a></dt>
<dt>Holbrook stone shower, <a href="#Page_128">128</a></dt>
<dt>Howard, E., <a href="#Page_155">155</a>-7</dt>
<dt>hunting meteorites, methods of, <a href="#Page_84">84</a>-100</dt>
</dl>
<dl class="index">
<dt class="center" id="index_I"><b>I</b></dt>
<dt>“ices,” <a href="#Page_106">106</a></dt>
<dt>Illinois Gulch iron, <a href="#Page_76">76</a></dt>
<dt>impactites, <a href="#Page_143">143</a>-5</dt>
<dt>India, Museum of the Geological Survey of, <a href="#Page_41">41</a></dt>
<dt>Indians, <a href="#Page_41">41</a>, <a href="#Page_76">76</a>, <a href="#Page_150">150</a></dt>
<dt>Institute for Nuclear Studies, <a href="#Page_168">168</a></dt>
<dt><a id="index_InstituteOfMeteoritics">Institute of Meteoritics</a>, <a href="#Page_5">5</a>, <a href="#Page_24">24</a>, <a href="#Page_26">26</a>-32, <a href="#Page_80">80</a>, <a href="#Page_84">84</a>, <a href="#Page_96">96</a>, <a href="#Page_168">168</a>, <a href="#Page_169">169</a>, <a href="#Page_171">171</a></dt>
<dt>intersecting lines of sight, <a href="#Page_84">84</a>-90</dt>
<dt>interstellar space, <a href="#Page_92">92</a>, <a href="#Page_171">171</a></dt>
<dt>irons, <a href="#Page_19">19</a>, <a href="#Page_36">36</a>, <a href="#Page_37">37</a>, <a href="#Page_39">39</a>, <a href="#Page_40">40</a>, <a href="#Page_41">41</a>, <a href="#Page_48">48</a>, <a href="#Page_73">73</a>, <a href="#Page_75">75</a>, <a href="#Page_76">76</a>, <a href="#Page_78">78</a>, <a href="#Page_82">82</a>, <a href="#Page_99">99</a>, <a href="#Page_116">116</a>, <a href="#Page_118">118</a>, <a href="#Page_120">120</a>, <a href="#Page_121">121</a>, <a href="#Page_128">128</a>, <a href="#Page_129">129</a>, <a href="#Page_133">133</a>, <a href="#Page_143">143</a>, <a href="#Page_150">150</a>, <a href="#Page_155">155</a>, <a href="#Page_163">163</a>, <a href="#Page_167">167</a>, <a href="#Page_174">174</a>-5, <a href="#Page_179">179</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_J"><b>J</b></dt>
<dt>Jones, W. B., <a href="#Page_179">179</a></dt>
<dt>Jupiter, <a href="#Page_102">102</a>, <a href="#Page_142">142</a>, <a href="#Page_160">160</a>, <a href="#Page_161">161</a>, <a href="#Page_164">164</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_K"><b>K</b></dt>
<dt>Kaalijarv crater, <a href="#Page_65">65</a></dt>
<dt>kamacite, <a href="#Page_124">124</a></dt>
<dt>Kasamatsu stone, <a href="#Page_74">74</a></dt>
<dt>Kayser, E., <a href="#Page_92">92</a></dt>
<dt>Kenton iron, <a href="#Page_75">75</a></dt>
<dt>Kilbourn stone, <a href="#Page_74">74</a></dt>
<dt>Klepesta, J., <a href="#Page_2">2</a></dt>
<dt>Krasnoyarsk iron, <a href="#Page_155">155</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_L"><b>L</b></dt>
<dt>laboratory procedures, <a href="#Page_5">5</a>, <a href="#Page_81">81</a>, <a href="#Page_83">83</a>, <a href="#Page_118">118</a>, <a href="#Page_120">120</a>, <a href="#Page_128">128</a>, <a href="#Page_167">167</a>-71</dt>
<dt>La Caille meteorite, <a href="#Page_78">78</a></dt>
<dt>L’Aigle stone shower, <a href="#Page_157">157</a>, <a href="#Page_158">158</a></dt>
<dt>Lake Murray iron, <a href="#Page_77">77</a>, <a href="#Page_79">79</a>, <a href="#Page_80">80</a>-3</dt>
<dt>Lake Okeechobee stone, <a href="#Page_78">78</a></dt>
<dt>LaPaz, L., <a href="#Page_178">178</a>, <a href="#Page_179">179</a></dt>
<dt>largest meteorites, <i>see</i> <a href="#index_WeightsAndWeighingOfMeteorites" class="ab">weights and weighing of meteorites</a></dt>
<dt>Leningrad (St. Petersburg), Academy of Science of, <a href="#Page_158">158</a></dt>
<dt>Leonard, F. C., <a href="#Page_178">178</a></dt>
<dt>Leonid shower, <a href="#Page_114">114</a>, <a href="#Page_115">115</a></dt>
<dt>Lick Creek iron, <a href="#Page_76">76</a></dt>
<dt>Londonderry Laboratory for Radiochemistry, <a href="#Page_168">168</a></dt>
<dt>Los Alamos Scientific Laboratory, <a href="#Page_171">171</a></dt>
<dt>“lost” meteorites, <a href="#Page_38">38</a>, <a href="#Page_40">40</a>, <a href="#Page_41">41</a>, <a href="#Page_80">80</a>, <a href="#Page_82">82</a>, <a href="#Page_95">95</a></dt>
<dt class="pb" id="Page_184">184</dt>
<dt>lunar craters, <a href="#Page_60">60</a>-4, <a href="#Page_179">179</a></dt>
<dd><i>see also</i> <a href="#index_MoonCratersOn" class="ab">moon, craters on</a></dd>
<dt>Lyrid shower, <a href="#Page_112">112</a>, <a href="#Page_114">114</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_M"><b>M</b></dt>
<dt>magic attributed to meteorites, <i>see</i> <a href="#index_Superstitions" class="ab">superstitions</a></dt>
<dt>Mars, <a href="#Page_160">160</a>, <a href="#Page_161">161</a></dt>
<dt>“Martian spaceship,” <a href="#Page_60">60</a></dt>
<dt>Maximilian I, <a href="#Page_152">152</a>-4</dt>
<dt>Mazapil iron, <a href="#Page_116">116</a></dt>
<dt>Mebane, A. D., <a href="#Page_177">177</a></dt>
<dt>Medvedev, P. I., <a href="#Page_10">10</a></dt>
<dt>Merrill, G. P., <a href="#Page_178">178</a></dt>
<dt>Mesaverde iron, <a href="#Page_76">76</a></dt>
<dt>metals, meteorites as sources of, <a href="#Page_174">174</a>-5</dt>
<dt>meteorite detectors, <a href="#Page_48">48</a>, <a href="#Page_52">52</a>, <a href="#Page_96">96</a>-100, <a href="#Page_178">178</a></dt>
<dt>meteoriteless meteorite crater, <a href="#Page_56">56</a></dt>
<dt>meteorite-planet hypothesis, <a href="#Page_140">140</a>, <a href="#Page_160">160</a>, <a href="#Page_163">163</a>, <a href="#Page_174">174</a></dt>
<dt>meteorite showers, <a href="#Page_73">73</a>-4, <a href="#Page_128">128</a>, <a href="#Page_157">157</a>, <a href="#Page_158">158</a>, <a href="#Page_159">159</a></dt>
<dt>meteorites, true or false, <a href="#Page_130">130</a>-3</dt>
<dt>meteoritics, <a href="#Page_5">5</a>, <a href="#Page_104">104</a>, <a href="#Page_166">166</a>-7</dt>
<dt>meteors, <a href="#Page_101">101</a>-17</dt>
<dt>meteor showers, <a href="#Page_103">103</a>, <a href="#Page_111">111</a>, <a href="#Page_112">112</a>-116, <a href="#Page_117">117</a>, <a href="#Page_152">152</a>, <a href="#Page_153">153</a></dt>
<dt>meteor steel, <a href="#Page_167">167</a></dt>
<dt>micro-meteorites, <i>see</i> <a href="#index_DustMeteoritic" class="ab">dust, meteoritic</a></dt>
<dt>minerals in meteorites, <a href="#Page_120">120</a>-6, <a href="#Page_156">156</a>, <a href="#Page_163">163</a></dt>
<dt>miners as meteorite finders, <a href="#Page_70">70</a>, <a href="#Page_76">76</a>, <a href="#Page_144">144</a></dt>
<dt>mining in space, <a href="#Page_162">162</a>, <a href="#Page_174">174</a>-6</dt>
<dt>Montezuma temple iron, <a href="#Page_76">76</a></dt>
<dt>moon, <a href="#Page_60">60</a>-4, <a href="#Page_140">140</a>, <a href="#Page_170">170</a></dt>
<dt><a id="index_MoonCratersOn">moon, craters on</a>, <a href="#Page_60">60</a>-4, <a href="#Page_179">179</a></dt>
<dt>Morito iron, <a href="#Page_128">128</a></dt>
<dt>Moscow, Academy of Sciences at, <a href="#Page_20">20</a></dt>
<dt>Mount Darwin, Tasmania, crater, <a href="#Page_65">65</a>;</dt>
<dd>silica-glass, <a href="#Page_143">143</a></dd>
<dt>Mount Joy iron, <a href="#Page_75">75</a>-6</dt>
<dt>Murfreesboro iron, <a href="#Page_76">76</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_N"><b>N</b></dt>
<dt>“natural nuclear explosion,” <a href="#Page_60">60</a></dt>
<dt>Neumann, J., <a href="#Page_158">158</a></dt>
<dt>nickel-iron, <a href="#Page_19">19</a>, <a href="#Page_32">32</a>, <a href="#Page_96">96</a>, <a href="#Page_98">98</a>, <a href="#Page_118">118</a>, <a href="#Page_120">120</a>, <a href="#Page_122">122</a>, <a href="#Page_123">123</a>, <a href="#Page_124">124</a>, <a href="#Page_126">126</a>, <a href="#Page_132">132</a>, <a href="#Page_143">143</a>, <a href="#Page_150">150</a>, <a href="#Page_161">161</a>, <a href="#Page_163">163</a>, <a href="#Page_170">170</a>, <a href="#Page_174">174</a></dt>
<dt><a id="index_NortonCountyFall">Norton County fall</a>, <a href="#Page_23">23</a>-34, <a href="#Page_90">90</a>, <a href="#Page_93">93</a>, <a href="#Page_94">94</a>, <a href="#Page_96">96</a>, <a href="#Page_126">126</a>, <a href="#Page_128">128</a>, <a href="#Page_130">130</a>, <a href="#Page_168">168</a></dt>
<dt>Novo-Urei stone, <a href="#Page_82">82</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_O"><b>O</b></dt>
<dt>obsidian mistaken for tektite, <a href="#Page_138">138</a>-9</dt>
<dt>octahedrites, <a href="#Page_120">120</a>, <a href="#Page_121">121</a></dt>
<dt>Odessa crater, <a href="#Page_43">43</a>, <a href="#Page_44">44</a>, <a href="#Page_52">52</a>, <a href="#Page_65">65</a>, <a href="#Page_66">66</a>, <a href="#Page_75">75</a></dt>
<dt>oldest collection of meteorites, <a href="#Page_76">76</a></dt>
<dt>oldest crater, <a href="#Page_52">52</a></dt>
<dt>Olivier, C. P., <a href="#Page_116">116</a>, <a href="#Page_177">177</a></dt>
<dt>Opava irons, <a href="#Page_76">76</a></dt>
<dt><a id="index_Orbits">orbits</a>, <a href="#Page_108">108</a>-112, <a href="#Page_160">160</a>, <a href="#Page_161">161</a></dt>
<dt>origin of meteorites, <a href="#Page_160">160</a>, <a href="#Page_163">163</a>, <a href="#Page_164">164</a>, <a href="#Page_174">174</a></dt>
<dt>Orionid shower, <a href="#Page_112">112</a>, <a href="#Page_114">114</a></dt>
<dt><a id="index_OvalShapedAreasOfFall">oval-shaped areas of fall</a>, <a href="#Page_32">32</a>, <a href="#Page_89">89</a>, <a href="#Page_94">94</a>, <a href="#Page_159">159</a></dt>
<dt>ownership of meteorites, <a href="#Page_36">36</a>, <a href="#Page_38">38</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_P"><b>P</b></dt>
<dt>Pallas, P. S., <a href="#Page_155">155</a></dt>
<dt>pallasites, <a href="#Page_122">122</a>, <a href="#Page_155">155</a></dt>
<dt>Pantar stone shower, <a href="#Page_74">74</a></dt>
<dt>parallax and parallactic displacement, <a href="#Page_105">105</a>, <a href="#Page_106">106</a></dt>
<dt>Paris, Museum of Natural History at, <a href="#Page_38">38</a>, <a href="#Page_158">158</a></dt>
<dt class="pb" id="Page_185">185</dt>
<dt>paths of meteors, <a href="#Page_84">84</a>-94, <a href="#Page_116">116</a></dt>
<dd><i>see also</i> <a href="#index_EarthTrace" class="ab">earth-trace</a>; <a href="#index_Orbits" class="ab">orbits</a>; <a href="#index_Speeds" class="ab">speeds</a>; <a href="#index_Trajectory" class="ab">trajectory</a>; <a href="#index_Velocity" class="ab">velocity</a></dd>
<dt>patterns, structural, <a href="#Page_120">120</a>, <a href="#Page_121">121</a>, <a href="#Page_172">172</a></dt>
<dt>Pawnee Indians, <a href="#Page_41">41</a></dt>
<dt>Peary, R. E., <a href="#Page_36">36</a>, <a href="#Page_37">37</a>, <a href="#Page_128">128</a></dt>
<dt>Perry, S. H., <a href="#Page_179">179</a></dt>
<dt>Perseid shower, <a href="#Page_114">114</a>, <a href="#Page_115">115</a></dt>
<dt>person struck by meteorite, <a href="#Page_70">70</a>-2, <a href="#Page_178">178</a>, <a href="#Page_179">179</a></dt>
<dt>piezoglyphs, <a href="#Page_131">131</a>, <a href="#Page_132">132</a></dt>
<dt>Pittsburgh iron, <a href="#Page_78">78</a>, <a href="#Page_80">80</a></dt>
<dt>plessite, <a href="#Page_124">124</a></dt>
<dt>plotting meteor paths, <a href="#Page_116">116</a></dt>
<dt>Plymouth meteorite, <a href="#Page_75">75</a></dt>
<dt><a id="index_PodkamennayaTunguska">Podkamennaya Tunguska</a> fall, <a href="#Page_50">50</a>, <a href="#Page_54">54</a>-60, <a href="#Page_65">65</a>, <a href="#Page_102">102</a></dt>
<dt>polishing meteorites, <a href="#Page_5">5</a>, <a href="#Page_118">118</a>, <a href="#Page_120">120</a>, <a href="#Page_123">123</a></dt>
<dt>Port Orford stony-iron, <a href="#Page_40">40</a></dt>
<dt>Prague Observatory, <a href="#Page_2">2</a></dt>
<dt>Prior, G. T., <a href="#Page_178">178</a></dt>
<dt>Proctor, R. A., <a href="#Page_164">164</a></dt>
<dt>Pultusk fireball, <a href="#Page_92">92</a></dt>
<dt>Purdue University, <a href="#Page_170">170</a></dt>
<dt>pure science, <a href="#Page_166">166</a></dt>
<dt>“purloined” meteorite, <a href="#Page_36">36</a>, <a href="#Page_39">39</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_Q"><b>Q</b></dt>
<dt>Quadrantid shower, <a href="#Page_114">114</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_R"><b>R</b></dt>
<dt>radiant of meteor shower, <a href="#Page_112">112</a>, <a href="#Page_113">113</a></dt>
<dt>radioactivities, <a href="#Page_5">5</a>, <a href="#Page_60">60</a>, <a href="#Page_133">133</a>, <a href="#Page_138">138</a>, <a href="#Page_168">168</a>, <a href="#Page_170">170</a>-1</dt>
<dt>Rafrüti iron, <a href="#Page_78">78</a></dt>
<dt>rainfall, connected with meteor</dt>
<dt>showers, <a href="#Page_117">117</a></dt>
<dt>random distribution, <a href="#Page_62">62</a></dt>
<dt>ray-craters, <a href="#Page_60">60</a>-4</dt>
<dt>recoveries of meteorites, <a href="#Page_14">14</a>-22, <a href="#Page_24">24</a>, <a href="#Page_26">26</a>-8, <a href="#Page_31">31</a>, <a href="#Page_33">33</a>, <a href="#Page_35">35</a>, <a href="#Page_75">75</a>-82, <a href="#Page_84">84</a>-100</dt>
<dt>Red River iron, <a href="#Page_41">41</a></dt>
<dt>re-entry, <a href="#Page_172">172</a>, <a href="#Page_173">173</a></dt>
<dt><a id="index_ReportsEyewitness">reports, eyewitness</a>, <a href="#Page_23">23</a>, <a href="#Page_24">24</a>, <a href="#Page_84">84</a>, <a href="#Page_86">86</a>, <a href="#Page_90">90</a>, <a href="#Page_92">92</a>, <a href="#Page_94">94</a>-5</dt>
<dt>reversed matter, <a href="#Page_56">56</a>, <a href="#Page_58">58</a>-60</dt>
<dt>Richland iron, <a href="#Page_75">75</a></dt>
<dt>Rigel, <a href="#Page_92">92</a></dt>
<dt>rocketry, <a href="#Page_110">110</a>, <a href="#Page_174">174</a>-6</dt>
<dt>Rojansky, V., <a href="#Page_58">58</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_S"><b>S</b></dt>
<dt><a id="index_SacredMeteorites">sacred meteorites</a>, <a href="#Page_147">147</a>-50</dt>
<dd><i>see also</i> <a href="#index_Superstitions" class="ab">superstitions</a></dd>
<dt>San Emigdio stone, <a href="#Page_80">80</a></dt>
<dt>satellites, man-made, <a href="#Page_172">172</a></dt>
<dt>Saturn’s rings, <a href="#Page_142">142</a></dt>
<dt>sawing meteorites, <a href="#Page_81">81</a>, <a href="#Page_167">167</a>-9</dt>
<dt>Schiaparelli, G. V., <a href="#Page_177">177</a></dt>
<dt>Schmidt, J. F. J., <a href="#Page_149">149</a></dt>
<dt>schreibersite, <a href="#Page_124">124</a></dt>
<dt>Scottsville iron, <a href="#Page_76">76</a></dt>
<dt>Seeläsgen iron, <a href="#Page_75">75</a></dt>
<dt>Shakespeare, meteors mentioned by, <a href="#Page_152">152</a></dt>
<dt>shale balls, <a href="#Page_48">48</a>, <a href="#Page_133">133</a></dt>
<dt>shapes of meteorites, <a href="#Page_18">18</a>, <a href="#Page_32">32</a>, <a href="#Page_126">126</a>-8, <a href="#Page_134">134</a>-7, <a href="#Page_140">140</a>, <a href="#Page_172">172</a></dt>
<dt>Shirihagi iron, <a href="#Page_150">150</a></dt>
<dt>“shooting stars,” <a href="#Page_104">104</a></dt>
<dt>showers, meteor, <a href="#Page_103">103</a>, <a href="#Page_111">111</a>, <a href="#Page_112">112</a>-116, <a href="#Page_117">117</a>, <a href="#Page_152">152</a>, <a href="#Page_153">153</a></dt>
<dt>showers, meteorite, <a href="#Page_73">73</a>, <a href="#Page_74">74</a>, <a href="#Page_128">128</a>, <a href="#Page_157">157</a>, <a href="#Page_158">158</a>, <a href="#Page_159">159</a></dt>
<dt>Siena fall, <a href="#Page_156">156</a></dt>
<dt>Sikhote-Alin fall, see <a href="#index_Ussuri" class="ab">Ussuri</a></dt>
<dt><a id="index_SilicaGlass">silica-glass</a>, <a href="#Page_50">50</a>, <a href="#Page_54">54</a>, <a href="#Page_143">143</a></dt>
<dd><i>see also</i> <a href="#index_Glass" class="ab">glass</a>; <a href="#index_Tektites" class="ab">tektites</a></dd>
<dt>silicate-siderites, <a href="#Page_122">122</a>, <a href="#Page_123">123</a></dt>
<dt>Sirius, <a href="#Page_92">92</a></dt>
<dt class="pb" id="Page_186">186</dt>
<dt>“skymarks,” <a href="#Page_92">92</a></dt>
<dt>smallest meteorites, <a href="#Page_48">48</a>, <a href="#Page_128">128</a></dt>
<dd><i>see also</i> <a href="#index_DustMeteoritic" class="ab">dust, meteoritic</a></dd>
<dt>Solar System, <a href="#Page_5">5</a>, <a href="#Page_111">111</a>, <a href="#Page_164">164</a>, <a href="#Page_175">175</a>-6</dt>
<dt>sounds made by falling meteorites, <a href="#Page_11">11</a>, <a href="#Page_12">12</a>, <a href="#Page_24">24</a>, <a href="#Page_25">25</a>,26, <a href="#Page_94">94</a>-5, <a href="#Page_148">148</a>, <a href="#Page_159">159</a></dt>
<dt>space exploration and ships, <a href="#Page_5">5</a>, <a href="#Page_168">168</a>, <a href="#Page_170">170</a>-6</dt>
<dt>space-probes, <a href="#Page_170">170</a>-1</dt>
<dt>space mining, <a href="#Page_162">162</a>, <a href="#Page_174">174</a>-6</dt>
<dt>spectra and spectrograms, meteor, <a href="#Page_107">107</a></dt>
<dt>spectroscopy, gamma-ray, <a href="#Page_171">171</a></dt>
<dt><a id="index_Speeds">speeds</a>, <a href="#Page_21">21</a>, <a href="#Page_32">32</a>, <a href="#Page_107">107</a>, <a href="#Page_108">108</a>, <a href="#Page_109">109</a>, <a href="#Page_110">110</a>-12, <a href="#Page_126">126</a>, <a href="#Page_172">172</a></dt>
<dt>Spencer, L. J., <a href="#Page_179">179</a></dt>
<dt>stainless steel, <a href="#Page_120">120</a>, <a href="#Page_122">122</a>, <a href="#Page_167">167</a></dt>
<dt><a id="index_StonesMeteoritic">stones, meteoritic</a>, <a href="#Page_28">28</a>-34, <a href="#Page_35">35</a>, <a href="#Page_70">70</a>, <a href="#Page_71">71</a>-2, <a href="#Page_73">73</a>-4, <a href="#Page_78">78</a>, <a href="#Page_80">80</a>, <a href="#Page_82">82</a>, <a href="#Page_118">118</a>, <a href="#Page_120">120</a>-4, <a href="#Page_128">128</a>, <a href="#Page_130">130</a>, <a href="#Page_131">131</a>, <a href="#Page_132">132</a>, <a href="#Page_133">133</a>, <a href="#Page_148">148</a>, <a href="#Page_156">156</a>-7, <a href="#Page_163">163</a></dt>
<dt>stony-irons, <a href="#Page_40">40</a>-1, <a href="#Page_118">118</a>, <a href="#Page_122">122</a>, <a href="#Page_124">124</a>, <a href="#Page_163">163</a></dt>
<dt>strata, effect of impact on, <a href="#Page_43">43</a>, <a href="#Page_44">44</a>-5, <a href="#Page_48">48</a>-51</dt>
<dt><a id="index_Superstitions">superstitions</a> about meteors and meteorites, <a href="#Page_25">25</a>, <a href="#Page_56">56</a>, <a href="#Page_82">82</a>, <a href="#Page_134">134</a>, <a href="#Page_136">136</a>, <a href="#Page_147">147</a>-52, <a href="#Page_154">154</a></dt>
<dt>swarms, meteorite, <a href="#Page_50">50</a></dt>
<dt>swarms, meteor-particle, <a href="#Page_111">111</a>, <a href="#Page_112">112</a>, <a href="#Page_114">114</a></dt>
<dt>Swindel, G. W., Jr., <a href="#Page_179">179</a></dt>
<dt>“swords from heaven,” <a href="#Page_150">150</a></dt>
<dt>Sylacauga stone, <a href="#Page_71">71</a>-2, <a href="#Page_74">74</a>, <a href="#Page_179">179</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_T"><b>T</b></dt>
<dt>taenite, <a href="#Page_124">124</a></dt>
<dt>tektite-obsidian test, <a href="#Page_138">138</a>-9</dt>
<dt><a id="index_Tektites">tektites</a>, <a href="#Page_134">134</a>-146, <a href="#Page_160">160</a></dt>
<dt>tests for true meteorites, <a href="#Page_130">130</a>-3</dt>
<dt>“thumb-prints,” <a href="#Page_131">131</a>, <a href="#Page_132">132</a></dt>
<dt><a id="index_Trajectory">trajectory</a>, <a href="#Page_90">90</a>, <a href="#Page_92">92</a>, <a href="#Page_173">173</a></dt>
<dt>tritium, <a href="#Page_170">170</a></dt>
<dt>Tucson iron, <a href="#Page_128">128</a></dt>
<dt>Tungus, <i>see</i> <a href="#index_PodkamennayaTunguska" class="ab">Podkamennaya Tunguska</a></dt>
<dt>twice-found meteorites, <a href="#Page_76">76</a></dt>
<dt>Tycho, lunar ray-crater, <a href="#Page_61">61</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_U"><b>U</b></dt>
<dt>University of California Radiation Laboratory, <a href="#Page_58">58</a></dt>
<dt>University of Chicago, <a href="#Page_168">168</a></dt>
<dt>University of New Mexico, <a href="#Page_24">24</a>, <a href="#Page_30">30</a></dt>
<dd><i>see also</i> <a href="#index_InstituteOfMeteoritics" class="ab">Institute of Meteoritics</a></dd>
<dt>University of Nebraska, <a href="#Page_30">30</a>, <a href="#Page_80">80</a></dt>
<dt>U. S. National Museum, <a href="#Page_40">40</a>, <a href="#Page_158">158</a></dt>
<dt><a id="index_Ussuri">Ussuri</a> fall, <a href="#Page_10">10</a>, <a href="#Page_11">11</a>-34, <a href="#Page_42">42</a>, <a href="#Page_50">50</a>, <a href="#Page_54">54</a>, <a href="#Page_65">65</a>, <a href="#Page_130">130</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_V"><b>V</b></dt>
<dt><a id="index_Vaporization">vaporization</a>, <a href="#Page_102">102</a>, <a href="#Page_107">107</a>, <a href="#Page_116">116</a>, <a href="#Page_126">126</a>, <a href="#Page_128">128</a>, <a href="#Page_143">143</a>, <a href="#Page_145">145</a>, <a href="#Page_162">162</a>, <a href="#Page_172">172</a>, <a href="#Page_174">174</a></dt>
<dt><a id="index_Velocity">velocity</a>, <a href="#Page_107">107</a>, <a href="#Page_108">108</a>, <a href="#Page_109">109</a>, <a href="#Page_171">171</a>, <a href="#Page_179">179</a></dt>
<dt>Venus, <a href="#Page_102">102</a>, <a href="#Page_162">162</a></dt>
<dt>Verbeek, R. D. M., <a href="#Page_140">140</a></dt>
<dt>Vienna, National History Museum of, <a href="#Page_41">41</a>, <a href="#Page_158">158</a></dt>
<dt>volcanic theories, <a href="#Page_138">138</a>, <a href="#Page_155">155</a>, <a href="#Page_156">156</a>, <a href="#Page_164">164</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_W"><b>W</b></dt>
<dt>Wabar craters, <a href="#Page_50">50</a>, <a href="#Page_65">65</a>, <a href="#Page_143">143</a>, <a href="#Page_162">162</a></dt>
<dt>Wasiutynski, J., <a href="#Page_63">63</a>-4, <a href="#Page_179">179</a></dt>
<dt>water, meteorites under, <a href="#Page_78">78</a></dt>
<dt>waves, air and water, <a href="#Page_12">12</a>, <a href="#Page_54">54</a>-5</dt>
<dt>weather, effect of meteoritic dust on, <a href="#Page_117">117</a></dt>
<dt>weathering of meteorites, <a href="#Page_38">38</a>, <a href="#Page_48">48</a>, <a href="#Page_52">52</a>, <a href="#Page_53">53</a>, <a href="#Page_54">54</a>, <a href="#Page_66">66</a>, <a href="#Page_133">133</a>, <a href="#Page_144">144</a></dt>
<dt><a id="index_WeightsAndWeighingOfMeteorites">weights and weighing of meteorites</a>, <a href="#Page_35">35</a>, <a href="#Page_36">36</a>, <a href="#Page_128">128</a>, <a href="#Page_130">130</a></dt>
<dt class="pb" id="Page_187">187</dt>
<dt>White, C. S., <a href="#Page_179">179</a></dt>
<dt>Widmanstätten pattern, <a href="#Page_120">120</a>, <a href="#Page_121">121</a>, <a href="#Page_122">122</a>, <a href="#Page_158">158</a></dt>
<dt>Whipple, F. L., <a href="#Page_177">177</a>, <a href="#Page_179">179</a></dt>
<dt>Willamette iron, <a href="#Page_36">36</a>, <a href="#Page_128">128</a>, <a href="#Page_129">129</a></dt>
<dt>Wold Cottage meteorite, <a href="#Page_156">156</a></dt>
<dt>Wolf Creek crater, <a href="#Page_52">52</a>, <a href="#Page_53">53</a>, <a href="#Page_65">65</a>, <a href="#Page_75">75</a>, <a href="#Page_133">133</a></dt>
</dl>
<dl class="index">
<dt class="center" id="index_Y"><b>Y</b></dt>
<dt>Yale University, <a href="#Page_41">41</a></dt>
<dt>young people and meteoritics, <a href="#Page_23">23</a>, <a href="#Page_24">24</a>, <a href="#Page_28">28</a>, <a href="#Page_34">34</a>, <a href="#Page_39">39</a>, <a href="#Page_90">90</a>, <a href="#Page_98">98</a>, <a href="#Page_99">99</a>, <a href="#Page_116">116</a></dt>
<dd><i>see also</i> <a href="#index_ReportsEyewitness" class="ab">reports, eyewitness</a></dd>
</dl>
<dl class="index">
<dt class="center" id="index_Z"><b>Z</b></dt>
<dt>Zhovtnevy Hutor fall, <a href="#Page_82">82</a></dt>
</dl>
<h2 id="c17"><span class="small">FOOTNOTES</span></h2>
<div class="fnblock"><div class="fndef"><a class="fn" id="fn_1" href="#fr_1">[1]</a>Also called <i>aerolites</i>.
</div><div class="fndef"><a class="fn" id="fn_2" href="#fr_2">[2]</a>The meteorites from this crater-producing fall have been found in both Haviland and Brenham Townships, Kiowa County, Kansas. Either of these names may therefore appear in the literature.
</div><div class="fndef"><a class="fn" id="fn_3" href="#fr_3">[3]</a>The meteorites from this crater-producing fall have been found in both Haviland and Brenham Townships, Kiowa County, Kansas. Either of these names may therefore appear in the literature.
</div><div class="fndef"><a class="fn" id="fn_4" href="#fr_4">[4]</a>453.59 grams = 1 pound.
</div><div class="fndef"><a class="fn" id="fn_5" href="#fr_5">[5]</a>A questionnaire for making an adequate report is obtainable by request from
the Institute of Meteoritics, The University of New Mexico, Albuquerque.
</div><div class="fndef"><a class="fn" id="fn_6" href="#fr_6">[6]</a>Readers who are advanced enough in astronomy to attempt plotting the
meteor paths can get the proper star-maps and record sheets for this purpose
by joining the American Meteor Society. Members must be at least 18 years
old, but applicants between 14 and 18 can become probational members. For
details write to Dr. C. P. Olivier, President, American Meteor Society, 521
North Wynnewood Avenue, Narberth, Pennsylvania.
</div><div class="fndef"><a class="fn" id="fn_7" href="#fr_7">[7]</a>Quite recently, a fourth division, the <i>tektites</i> (discussed in the <a href="#c11">next chapter</a>),
has been recognized by some authorities.
</div><div class="fndef"><a class="fn" id="fn_8" href="#fr_8">[8]</a>Discussed in <a href="#c13">Chapter 12</a>.
</div><div class="fndef"><a class="fn" id="fn_9" href="#fr_9">[9]</a>The Acts of the Apostles, 19:35.
</div><div class="fndef"><a class="fn" id="fn_10" href="#fr_10">[10]</a>Also <i>baetyl</i> and <i>baetulus</i>, from the Greek word <i>baitylos</i>, a term used for
sacred meteorites and stones.
</div><div class="fndef"><a class="fn" id="fn_11" href="#fr_11">[11]</a>This metallic mass was the first stony-iron meteorite to be identified as
such. The <i>pallasites</i>, which make up an important subdivision of the stony-iron
meteorites, were named in honor of Pallas.
</div><div class="fndef"><a class="fn" id="fn_12" href="#fr_12">[12]</a>Very recently, some authorities have concluded that there must have been
not one but several meteorite-planets.
</div>
</div>
<div class="pb" id="Page_188">188</div>
<h3 id="c18">Space Nomads
<br />Meteorites in Sky, Field, and Laboratory
<br />By Lincoln LaPaz and Jean LaPaz</h3>
<p>Meteorites are the real tokens of space!
They are samples of cosmic matter we can
actually take in our hands. Science values
them greatly as specimens of <i>the only tangible</i>
substances we have from remote and
inaccessible regions of the universe.</p>
<p>These mysterious “space nomads” are revealing
to today’s scientists many amazing
and usable facts about conditions in outer
space, about the age of our Solar System,
and even about the probable constitution
of our own home planet.</p>
<p>This is an essential book for everybody who
is keeping up with space science and wishes
to be well posted on these interesting but
potentially dangerous co-voyagers that the
astronauts may encounter.</p>
<div class="pb" id="Page_189">189</div>
<p>You will also see in SPACE NOMADS:</p>
<p>The awesome event a meteorite-fall can
be, with its violent sound and light effects,
and its terrific impact.</p>
<p>The excitement and the know-how of the
hunt for these cosmic missiles.</p>
<p>How to tell the difference between a true
meteorite and a mistaken one. Ditto, meteorite
craters.</p>
<p>How to make your own contribution to
science by knowing the right way to observe
and report meteors and meteorites.</p>
<p>What is inside them, and how they vary
in content and structure.</p>
<p>The moon as a meteorite target.</p>
<p>The strange history of the subject—the
amusing superstitions and fantastic notions
believed until recently about “shooting
stars” and “stones falling from the
sky.”</p>
<p>And more.</p>
<p class="tb">Here is an easy but sound introduction to
the rapidly developing science of meteoritics.
All of the information is up-to-date,
much of it firsthand, for the authors
are themselves professional meteoriticists.
Daily they are engaged in fieldwork, laboratory
analysis, and advanced research at
one of the world’s chief centers for this
study. (See back of jacket.)</p>
<p class="center">A HOLIDAY HOUSE BOOK
<br />12 UP <span class="hst">$3.95</span></p>
<p class="center"><i>Jacket by Leo Manso</i></p>
<div class="img" id="fig63">
<img src="images/p60.jpg" alt="" width="446" height="500" />
<p class="pcap"><span class="jr">HARVEY CAPLIN PHOTO</span>
Lincoln LaPaz</p>
</div>
<p>On the moon is a ray-crater named LaPaz
in honor of the man who has had a major
part in establishing the highly significant
theory that the lunar ray-craters were made
by the impact of meteorites. Lincoln LaPaz
is a leading pioneer as well as a widely
recognized authority in meteoritics, an important
branch of astronomy. He was born
on Lincoln’s birthday, in Wichita, Kansas,
where he grew up. Although both his
master’s degree, at Harvard, and his doctorate,
at Chicago, were in mathematics,
his chief interest since boyhood has been
in meteorites and meteors. Today he is
Director of the Institute of Meteoritics at
the University of New Mexico, where he
also heads the Division of Astronomy.</p>
<div class="img" id="fig64">
<img src="images/p60a.jpg" alt="" width="385" height="500" />
<p class="pcap"><span class="jr">RAVINI PHOTO</span>
Jean LaPaz</p>
</div>
<p>Jean LaPaz was born in Hanover, New
Hampshire. Since girlhood she has been
close to her father in his fascinating work.
When she was a high-school student in
Ohio, she did some serious fieldwork as
a member of the Ohio State University
Meteorite Expeditions. Later, she received
both a Bachelor of Science degree in geology
and a Master of Arts in English from
the University of New Mexico. Science and
Literature continue to be her mutually
favoring interests.</p>
<h2>Transcriber’s Notes</h2>
<ul><li>Retained publication information from the printed edition: this eBook is public-domain in the country of publication.</li>
<li>Silently corrected a few palpable typos.</li>
<li>In the text versions only, text in italics is delimited by _underscores_.</li></ul>
<div>*** END OF THE PROJECT GUTENBERG EBOOK 52848 ***</div>
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