stone rock of all sizes. Where could white sandstone come from in a limestone desert? It is necessary to look within the crater again and see bared deep below, 300 feet or more, a belt of white sandstone. On the east and west slopes especially, the blocks tossed out have astonishing proportions. The largest is estimated to weigh more than 7,000 tons. One slab 10 feet thick leans drunkenly, like an old menhir, fully a half mile from the crater. It is estimated that the meteorite displaced more than 200,000,000 tons of rock. In an instant it removed material equal to a quarter of the amount of material excavated in digging the Panama Canal. The rock strata have been lifted up, wrenched, and wedged into seemingly impossible angles. On the south side the rock layers have been lifted almost vertical, and there they stand, grotesquely yet significantly, pointing toward the north. THE DIFFERENCE BETWEEN METEORS AND METEORITES For thirty years, at least, Meteor Crater has been less a bowl than a football for scientists, professional and amateur, in the fields of astronomy, geology, physics, engineering, and even ballistics. Most authorities agree now that the crater is indeed the mark of a gigantic mass of meteorites. Probably it can be considered the tomb of a small dead comet. The "accident" may have happened in this manner: A close-knit mass of nickeliron, débris of a burned-out comet, came bowling along the elliptical course around the sun which it once traveled in a more brilliant fashion. Its route happened to coincide with that of the earth-a rare circumstance, indeed. Some hundreds of miles from the earth the comet may have snagged itself in the gravity net of the planet. The mass of iron swung in, traveling probably between 25 and 40 miles per second. Our atmosphere began to put on pressure to reduce the meteorite's celestial momentum to earth's traffic laws. Terrific speed created tremendous friction. Rich oxygen in the earth's atmosphere blowtorched the iron. The dead comet shot downward glowing like a brake shoe. Earth's deep air cushion of atmosphere was unequal to this Juggernaut of metal, with a diameter variously estimated at from 300 to 500 feet and a minimum weight of a million tons. Supersunlight blazed down on desert and mountain for a moment; then plain and peak shook with a dull, earthquaking thud. Into the air billowed a cloud of rock dust. Explosions rent the cloud. Jets of steam shot like geysers through it. Dust billowed again and the wind swept it far abroad. Clearing air exposed a great circular pockmark in the grassless desert. While few incidents in Nature are more dramatic than the arrival of a meteor, there are few objects of less dramatic appeal than a meteorite. A meteorite is a meteor come to earth. Meteors pencil the calm of a starlit sky with streaks of light. Their fire rises quickly to crescendo and dies. Their usual fate is to perish in the blaze of their own histrionics. Some escape the clutches of gravity and dash back into the black alleys of the universe once more. Only occasionally does the end of a meteor's arc touch earth, and when some person finds the "pot" of iron or stone it is always a hideous black thing seared by the fires of friction. It is hard to believe that the dark-brown, misshapen lumps one sees in the museums carrying the label "meteorite" are the glorious night riders of the heavens. Visitors to the American Museum of Natural History, in New York, approach that hall of wonders for the first time with a variety of expectations. They think, perhaps, to walk in upon a collection of thick-hided prehistoric animals. Some hope to meet at the door the stuffed representatives of the modern animal and bird kingdoms. It is with considerable surprise, therefore, that nearly everyone enters the large elliptical reception hall, the place of honor, to see not a diplodocus, not bears or birds, not flowers, not Indian families in wax, not gems or beautiful stones, but a score of white pedestals, on each of which is a rusty, weathered, meteorite mass-a meteorite collec tion. To the left of the entrance is Peary's Cape York mass, reigning monarch of meteorites. Yet one must have something of the scientist's love of abstract facts to work up any enthusiasm over this prize. It is a pitted mass about as large as an old-fashioned concert grand piano. But no pair of piano movers could budge it, since this meteorite is solid nickel-iron and weighs 361⁄2 tons. A view of it does help Photograph by Capt. Albert W. Stevens AN AERIAL VIEW OF SOUTH CAMP, AT METEOR CRATER Men conducting recent drilling operations lived in the bunkhouses in the middle foreground. The white gash to the right shows where rain has cut a creek bed through the tons and tons of fine white rock flour pulverized by the impact. The first drilling for the meteorite was begun at the center of the pit, and the trail visible on the far side was made to bring down machinery and supplies. sion. The sides all around are steep and ragged. A trip to the bottom, one rightly suspects, is an adventure of inverted mountain-climbing. It is disturbing to revisualize the collision. One suddenly remembers the favorite problem of the physics teacher in high school. What will happen when an irresistible force meets an immovable object? Here is the answer! Almost! A FOOTBALL BOWL AWAITING A The celestial shot that blasted the crater might have landed in some other place. On Manhattan Island the pit would be a considerable amphitheater. The main mass of skyscrapers on the lower end of the famous island could be dropped into the hole and only the Woolworth Tower would project prominently above the rim. What a pity some university doesn't locate beside it. Think of a bowl 25 times the size of Yale's! Fully to appreciate the dimensions of this splash in stone made by a gigantic iron meteorite, one must walk around the rim. It is a three-mile tramp. The pit is 4,200 feet across, roughly four-fifths of a mile. All about are evidences of a terrific impact. The slopes of the rim are littered with crushed limestone and sand stone rock of all sizes. Where could white sandstone come from in a limestone desert? It is necessary to look within the crater again and see bared deep below, 300 feet or more, a belt of white sandstone. On the east and west slopes especially, the blocks tossed out have astonishing proportions. The largest is estimated to weigh more than 7,000 tons. One slab 10 feet thick leans drunkenly, like an old menhir, fully a half mile from the crater. It is estimated that the meteorite displaced more than 200,000,000 tons of rock. In an instant it removed material equal to a quarter of the amount of material excavated in digging the Panama Canal. The rock strata have been lifted up, wrenched, and wedged into seemingly impossible angles. On the south side the rock layers have been lifted almost vertical, and there they stand, grotesquely yet significantly, pointing toward the north. THE DIFFERENCE BETWEEN METEORS AND METEORITES For thirty years, at least, Meteor Crater has been less a bowl than a football for scientists, professional and amateur, in the fields of astronomy, geology, physics, engineering, and even ballistics. Most authorities agree now that the crater is indeed the mark of a gigantic mass of meteorites. Probably it can be considered the tomb of a small dead comet. The "accident" may have happened in this manner: A close-knit mass of nickeliron, débris of a burned-out comet, came bowling along the elliptical course around the sun which it once traveled in a more brilliant fashion. Its route happened to coincide with that of the earth-a rare circumstance, indeed. Some hundreds of miles from the earth the comet may have snagged itself in the gravity net of the planet. The mass of iron swung in, traveling probably between 25 and 40 miles per second. Our atmosphere began to put on pressure to reduce the meteorite's celestial momentum to earth's traffic laws. Terrific speed created tremendous friction. Rich oxygen in the earth's atmosphere blowtorched the iron. The dead comet shot downward glowing like a brake shoe. Earth's deep air cushion of atmosphere was unequal to this Juggernaut of metal, with a diameter variously estimated at from 300 to 500 feet and a minimum weight of a million tons. Supersunlight blazed down on desert and mountain for a moment; then plain and peak shook with a dull, earthquaking thud. Into the air billowed a cloud of rock dust. Explosions rent the cloud. Jets of steam shot like geysers through it. Dust billowed again and the wind swept it far abroad. Clearing air exposed a great circular pockmark in the grassless desert. While few incidents in Nature are more dramatic than the arrival of a meteor, there are few objects of less dramatic appeal than a meteorite. A meteorite is a meteor come to earth. Meteors pencil the calm of a starlit sky with streaks of light. Their fire rises quickly to crescendo and dies. Their usual fate is to perish in the blaze of their own histrionics. Some escape the clutches of gravity and dash back into the black alleys of the universe once more. Only occasionally does the end of a meteor's arc touch earth, and when some person finds the "pot" of iron or stone it is always a hideous black thing seared by the fires of friction. It is hard to believe that the dark-brown, misshapen lumps one sees in the museums carrying the label "meteorite" are the glorious night riders of the heavens. Visitors to the American Museum of Natural History, in New York, approach that hall of wonders for the first time with a variety of expectations. They think, perhaps, to walk in upon a collection of thick-hided prehistoric animals. Some hope to meet at the door the stuffed representatives of the modern animal and bird kingdoms. It is with considerable surprise, therefore, that nearly everyone enters the large elliptical reception hall, the place of honor, to see not a diplodocus, not bears or birds, not flowers, not Indian families in wax, not gems or beautiful stones, but a score of white pedestals, on each of which is a rusty, weathered, meteorite mass-a meteorite collection. To the left of the entrance is Peary's Cape York mass, reigning monarch of meteorites. Yet one must have something of the scientist's love of abstract facts to work up any enthusiasm over this prize. It is a pitted mass about as large as an old-fashioned concert grand piano. But no pair of piano movers could budge it, since this meteorite is solid nickel-iron and weighs 361⁄2 tons. A view of it does help WHERE SOLID ROCK FLOWED LIKE WHEAT: THE OUTER SLOPES OF THE CRATER Hopi Indians regard Meteor Crater with superstitious awe. Members of the tribe come periodically to obtain the powdery white rock flour from the outer slopes for use in religious ceremonials. Rock flour consists of grains of sandstone pulverized by shock (see page 729). THE THREE-MILE PATH AROUND THE INNER RIM LEADS OVER BROKEN ROCK Minute diamonds have been found in carbon pockets within the meteorites of Meteor Crater. Note the angle at which these rock strata have been propped up. WHERE MOUNTAIN CLIMBING IS INVERTED: THE FACE OF THE RIM Dark-red iron stains in the white rock identify meteoric iron within the crater. Digging usually discloses a badly rusted object called a "shale ball," the nucleus of which is nickel-iron. Twenty-nine of the 90 known elements, which are Nature's building blocks for water, land, and air, have been found in meteorites. The fragments from the Meteor Crater region contain 93 per cent iron, 4 to 8 per cent nickel, and carbon, phosphorus, cobalt, sulphur, and silicon. |