1. A METEORITE FALLS IN THE TAIGA, U.S.S.R.
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.
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.)
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.
The flash of the fireball and the loud noises that followed it 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.
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.
Even deep in the mineshaft, the vibrations in the air were strong enough to snuff out the miners’ lamps, leaving the men in darkness.
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.
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 the place of fall. It turned out that they were only about 9 miles from it.)
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.
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.
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.
Such was the inhospitable region in which the Ussuri, or (as 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.
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.
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.
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.
COURTESY OF E. L. KRINOV Splintered and broken trees at the site of the Ussuri fall.
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.
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.
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.
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.
COURTESY OF E. L. KRINOV Workmen excavating one of the large craters formed by the impact of the Ussuri meteorites.
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.”
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.
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.
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.
COURTESY OF E. L. KRINOV A nickel-iron meteorite from the Ussuri fall imbedded in the trunk of a cedar tree.
Many whole individual meteorites also were recovered. These were almost always covered by a thin, smooth “glaze” known as fusion crust. 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.
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.
COURTESY OF E. L. KRINOV An individual Ussuri meteorite with fusion crust and characteristic surface sculpturing produced during high-speed flight through the resisting atmosphere.
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.