Part 3

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.

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.

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.

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.

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.

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.

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.

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 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.

Eyewitnesses of this meteorite fall said that at the time the fireball passed near them, they felt almost unbearable heat.

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.

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.

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 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.

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.

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!

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?

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.

Suppose that the situation shown in the first diagram 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 second diagram. 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 _reversed matter_, _anti_-matter, or, as it was first called by V. Rojansky, _contraterrene_ 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.

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.

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.

The effect of such an energy release as would accompany the infall of a contraterrene meteorite would be a _natural_ 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, p. 102.)

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.

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.

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 _ray-craters_ 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.

In earlier days, most scientists believed that the craters on the moon had _all_ been formed by volcanic action. Now the pendulum of scientific opinion seems to have swung toward the view that _all_ 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.

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 _two_ quite distinct types. No single “explanation” can be expected to explain satisfactorily lunar features as strikingly different as:

First, the rare and distinctive _ray-craters_ 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.)

Second, the ordinary or “run-of-the-mill” craters sprinkled in profuse but non-random fashion over the visible face of our satellite.

The ray-craters on the moon are the counterparts of the meteorite craters on the earth. This fact is shown not only by their 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).

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.

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 _convection_ processes.

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 _controlled_ convection in layers of _liquids_ rather than gases. Laboratory investigation of the effects produced by convection processes in heated liquids formed the basis for Wasiutynski’s new theory.

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, 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.

RECOGNIZED METEORITE CRATERS OF THE WORLD

NAME LOCATION DATE OF RECOGNITION

Canyon Diablo Coconino County, Arizona 1905 Odessa Ector County, Texas 1929 Henbury McDonnell Ranges, Central 1932 Australia Wabar Rub’ al Khali, Arabia 1932 Campo del Cielo Gran Chaco, Argentina 1933 [2]Haviland (Brenham) Kiowa County, Kansas 1933 Mount Darwin Tasmania 1933 [3]Podkamennaya Tunguska Yeniseisk District, Siberia 1933 Box Hole Station Plenty River, Central 1937 Australia Kaalijarv Oesel, Estonia 1937 Dalgaranga Western Australia 1938 Ussuri (Sikhote-Alin) Eastern Siberia 1947 Wolf Creek Wyndham, Kimberley, 1948 Western Australia Aouelloul Adrar, Western Sahara 1952

5. HEAVEN KNOWS WHERE OR WHEN

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.

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.

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.

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 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.

Studies have shown that the people of the earth have a great deal more to do with “concentrations” of meteorite recoveries than anything else. _Population density_ 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.

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.

A second factor is the _degree of civilization_ reached by the 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.

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.

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.

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 73, 74 is a listing of some of the meteorites that have struck and damaged buildings during the last 150 years or so. The items included in this list were chosen on the basis of interest, authenticity, and concreteness of detail.

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.

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.

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.

Investigation showed that this stone had indeed fallen through 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.

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.

He tried to cut the stone on an emery wheel, but it was too hard.

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.

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.

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.