Imagine yourself standing on the broken crater rim where, in Bedouin lore, the endless shifting sands of the Rub' al-Khali cover the fire-blackened ruins of the legendary city of Wabar. It is a clear night in the immense marches of the great Arabian desert, the mysterious Empty Quarter. The stars wink, crystallize and close.
It is a place touched with awe. Standing there you might scan the vast sky and feel very keenly the implications and excitement of space flight. Your senses might leap to capture some human and reasonable notion of the environment of outer space and its effect upon a flying object.
But would you think to look underfoot? Would it cross your mind to search the sands of Wabar for a clue to space flight? Probably not. And yet, by the light of day you would find buried fragments of meteorites, the only known objects that have hurtled through outer space and come to rest on earth. The meteorite crater at Wabar, long known to the Bedouin of the Empty Quarter and first mapped by H. St. John Philby in 1932, turns the questing mind to ancient times and points the scientific researcher to the future.
The meteorite fragments discovered by Philby at Wabar (near al-Hadidah) are not the only such space objects to be found in the Rub' al-Khali. Nor were they the first to be discovered on the surface of the vast Arabian sub-continent.
A nineteenth-century discovery did precede Philby's al-Hadidah meteorite discovery by almost ninety years. Two masses of meteoric iron weighing 131 and 137 pounds were found in 1863 in the Najd, the mountainous area of east central Saudi Arabia. A "grey bronzite-chondrite" meteorite which fell into the desert in the Hijaz, the western coastal section of Saudi Arabia, was reported in a French scientific journal as having struck the earth on a spring night in 1910. Then in January, 1931 an English explorer, Bertram Thomas, picked up a meteorite fragment from the sands at al-Buh, in the Sawahib dunes of the central Rub' al-Khali.
In recent years, the once remote expanse of the ‘Rub al-Khali (the name means, literally, the Empty Quarter, a vague and poetic designation of undetermined origin) has been surveyed and mapped by exploration parties of the Arabian American Oil Company. Aramco geologists have made a number of interesting additions to the inventory of Rub' al-Khali meteorites since 1952.
Donald August Holm, an Aramco senior geologist and devoted student of the geomorphology (the changing surface) of the Empty Quarter, recently undertook to survey the specimens of exotic rocks brought into Dhahran, Aramco headquarters, from geological field parties in the past decade. Holm is preparing a scientific paper on the meteorites of the Rub' al-Khali in response to the increasing inquiries that have come to Aramco from scientists who may help pave the way to interstellar flight by way of a second look underfoot.
According to Holm, "There are at least ten localities in the Rub' al-Khali where meteoric materials have been found. Of these, six were found by Aramco personnel, one by Bertram Thomas and three by Philby."
Philby, a well-known British explorer and author, reached the al-Hadidah craters in 1932. He had reason to believe that he might discover the lost ruins of Wabar. But he was destined to disappointment. He wrote:
"And now I was about to draw the veil from the mysteries on which I had pondered so long with all the devotion of a pilgrim . . . I reached the summit and in that moment fathomed the legend of Wabar. . . a city destroyed by fire from heaven for the sins of its king . . . This may indeed be Wabar, of which the Bedouin speak, but it is the work of God, not man."
Philby at first assumed that the several craters he found at al-Hadidah were of volcanic origin. He then mapped the area indicating the positions, contours and depths of two craters and suggested the positions of several others which had been covered over by sand. (Today only one crater rim remains above the sweep of the sand and, according to Holm, it will disappear beneath the dunes in another decade.) Philby then deduced correctly that he had discovered meteorite craters and not volcanic craters. Such a find, Holm points out, "is still quite rare in nature,"
None of the newer locations, as Holm notes, have yielded any craters. This disappearing al-Hadidah (Wabar) crater is the only evidence left in the great desert of the force and heat generated by the fall of a meteorite.
How recent was the meteorite fall in the Rub' al-Khali? No one can yet be certain, Holm says. Did the fragments fall in a single shower? Not enough data to give a firm answer, according to Holm.
The reluctance of the scientist to speculate doesn't burden the rich trove of oral desert lore handed on by the nomadic Bedouin tribes who have frequented the Rub' al-Khali for generations. One of the most enticing images of desert mystery dangled before explorers by Bedouin guides has been the enduring report of a piece of iron "as big as a camel." No one has ever found this huge meteorite. But not long ago a visitor to a Bedouin tent asked his desert host if he had ever heard tell of this mysterious object.
"Yes," the Bedouin said without pause.
"Have you seen it?" the visitor asked.
"No, but I know where it is."
"At the ruins of the castles of Wabar," the Bedouin replied.
"Can you find Wabar?"
"No, that is buried too."
One by one the mysteries of the 230,000-square-mile Rub' al-Khali have given way to the searching eye of science. But the vast reaches of the world's largest desert still excite the fancy of men in quest of knowledge about the first "space ships"—the meteorites.
A Down-to-Earth Look at Meteors and Meteorites
During his early history, man looked upon "shooting stars" as omens of pestilence and death. More recently, however, the fiery bolts have been viewed with increasing favor, especially by scientists who covet them as the only outer-space material available for direct examination.
Accounts of meteors dot ancient literature. The word "meteor" is of Greek origin and was used to denote "things in the air." But it was not until the nineteenth century that the study of meteors and meteorites took a serious turn. (A meteorite is a meteor fallen to earth.) On November 13, 1833 the sky over North America fairly glowed with a shower of these celestial bodies estimated at 200,000 between dusk and dawn. The brilliance and duration of the aerial display piqued the curiosity of astronomers all over the world. One of the first facts they established is that meteors seem to rain on the earth at about the same time a comet sparkles briefly millions of miles out in space. (Comets are, in a sense, large meteors that maintain regular orbits, like those of the planets, around the sun.) Cross-checking meteor reports in ancient literature, the scientists found that the appearance of meteors and comets had regularly coincided. What their relationship is, is still open to speculation. It may be that meteors are the residue of comets, pulled into the earth's atmosphere when the comet, in its own orbit, speeds past. Or it may be that the comets themselves attract the meteors in outer space and carry them along on their journey toward the earth.
Whatever the means of their arrival, meteors arrive spectacularly. Plummeting through the vacuum of space, they enter the earth's blanket of air at acute angles to this planet. A slow meteor hits the relatively thick atmosphere at 25,000 miles per hour; fast bodies may be traveling at as much as 160,000 miles per hour. Fast or slow, their velocity is great enough to cause the intense friction that eventually vaporizes them. They literally burn up, causing the incandescent arc in the sky. Low-flying meteors hurtle past witnesses with the rumble of an avalanche and may fly to bits with a thunderous roar. It is small wonder that they left the ancients awestruck.
Scientists claim that at least 75,000,000 meteors enter the earth's atmosphere every day and that one or two may last long enough to reach ground-level. Some meteors no larger than one-tenth inch in diameter and weighing a fraction of a gram appear as huge fireballs because of their glow. These small meteors burn up long before they get close to the earth, but those as large as a football when they contact the atmosphere stand a chance of reaching the earth, although they're no bigger than peas when they hit.
Others of frightening bulk have invaded the earth's atmosphere and have retained enough size to considerably dent the earth's crust. One of these, weighing millions of tons, fell long ago in what is now Arizona. It gouged out a crater 600 feet deep and 4,000 feet across. The meteorite itself has never been found, but drilling samples indicate that it may have burrowed down some 1200 feet under the crater. The crater at Wabar, Saudi Arabia, 300 feet wide and 40 feet deep, and 13 large craters in central Australia also prove that the earth occasionally takes a heavyweight punch from a meteorite.
Meteorites recovered by scientists are either stone or metal. The largest stone meteorite, found on Long Island, New York, weighed 1,230 pounds. Metal meteorites, usually iron or nickel, tend to be larger. One weighing 79,000 pounds was found in Greenland, and another of mammoth size found in Africa in 1947 weighed 132,000 pounds!
Scientists have subjected these outer-space visitors to every conceivable test in an effort to learn more about the building blocks of other worlds. Perhaps the most significant result so far is that they have found no element in either stone or metal meteorites that is not also found on earth. And the newest—and perhaps most exciting—revelation came this year from an old meteorite. In May, 1864 a stone meteorite fell near Toulouse, France. French scientists examined it and announced that it had an unusual chemical composition, but almost a hundred years elapsed before better techniques of chemical and physical analyses were applied to it. The analyses yielded carbon compounds akin to those found only in plants and animals. Although some scientists warned against jumping to conclusions, those who examined the French meteorite said that their findings provided "the first physical evidence for the existence of forms of life beyond our planet."