REVIEW of REVIEWS

Seek New Facts Regarding Moon

Selenologists Not Satisfied With Old Theories—Believe There May be Active Volcanoes on Pale Satellite.

WALDEMAR KAEMPFFERT June 1 1929
REVIEW of REVIEWS

Seek New Facts Regarding Moon

Selenologists Not Satisfied With Old Theories—Believe There May be Active Volcanoes on Pale Satellite.

WALDEMAR KAEMPFFERT June 1 1929

Seek New Facts Regarding Moon

REVIEW of REVIEWS

Selenologists Not Satisfied With Old Theories—Believe There May be Active Volcanoes on Pale Satellite.

WALDEMAR KAEMPFFERT

NOT SO long ago, astronomers believed that they knew all there was to know about the moon. It was a dead globe of chilled lava which had been so painstakingly mapped that it hardly repaid detailed study. But special students of the moon—selenologists they call themselves—are not at all satisfied with this complacent explanation. According to Waldemar Kaempffert, writing in The New York Times, “thousands and thousands of extinct craters are no longer casually dismissed as evidence of terrific upheavals.” Mr. Kaempffert continues: “Are they perhaps the marks of a bombardment that lasted for geological epochs during which meteors, great and small, rained down, as some physicists now suppose? Patient study of the maps made of the lunar surface during the last 200 years reveals discrepancies that cannot be attributed to faulty observation. Is it possible that the moon is not yet dead—that there may still be an active Vesuvius or two on that pitted surface? So far from being a celestial body which by reason of its very nearness offered no new problems to science, the moon still has its riddles.

“Such, at least, is the conclusion that has been reached in the Carnegie Institution of Washington. Under the guidance of Dr. Frederick E. Wright, the geophysicists there will re-address themselves to the age-old task of finding out of what the moon is made. They will interpret what is seen through the telescope and on photographs in the light of the new geology—in the light of knowledge gained by trying to reproduce in the laboratory the conditions under which rocks were formed on the earth. No doubt they will pelt plastic miniatures of the moon with balls fired from a kind of gun to ascertain whether the strange craters seen on the moon were indeed the result of bombardment, and manufacture miniature eruptions to discover if at least some of the gigantic lunar formations were caused by a mighty cooking and bubbling. And no doubt, like Professor Wood, they will examine the lunar surface with rays that we never see, and thus identify compounds as if they had taken a sample from the moon and analyzed it in their retorts and test tubes. In a word, the moon has become a problem for the geophysicist rather than for the astronomer’s exclusive enquiry. The first step in this re-examination must involve the moon’s origin—the conditions under which the moon tore itself away from the earth. A scenario of science must be written for a kind of motion picture which will be far more exciting and dramatic than the puny human conflicts that thrill us on the screen, and which will trace what is, in effect, the tragedy of a planet. The early scenes are very clear; the later scenes are those that must now be written by the geophysicists of the Carnegie Institution of Washington.

“Hundreds of millions of years ago the earth was undoubtedly a perfect sphere of gas. The late Sir George Darwin, son of the great Charles, projected himself-back mathematically to that remote time, and so did Henri Poincaré. They beheld in their equations a spectacle the like of which was never presented elsewhere in the solar system—beheld the gaseous earth spinning faster and faster on its axis so that it ceased to be a perfect sphere and assumed the shape of a spheroid. In their mathematical minds’ eyes they could see millions of years slipping by and the earth spinning still more dizzily. Additional equations revealed the earth, under this accelerating rotation, changing from a spheroid into something shaped like an egg.

“The egg-shaped mass of gas cooled, became a liquid and continued to spin faster and faster. Darwin saw a temporary collapse, causing the egg to assume the shape of a pear. More millions of years elapsed. The stalk end of the pear developed a bulb and the waist of the stalk became thinner and thinner.

“So fast was the earth now spinning that the day was only three hours long, a velocity sixteen times faster than that of a rifle bullet. Tides raised by the sun aided centrifugal force in distorting the earth. The liquid pear, coated by this time with a crust some thirty-five miles thick, could not withstand the combination. A cataclysm of terrific magnitude occurred. Five thousand cubic miles of matter constituting the bulb was wrenched loose. In that stupendous convulsion the moon was born. Some astronomers profess to see in the basin now filled by the Pacific Ocean the scar of that planetary catastrophe.

“No other satellite had an origin like this. To an astronomer on Mars the earth and the moon appear as they really are—a double planet of marvelous beauty. Physicists have thrown the moon on their mathematical scales. It weighs seventy-three trillion tons—one eightieth of the earth’s mass. Of all satellites in the solar system none approaches the moon in size and mass.

“The moon was not forthwith hurled 239,000 miles into space, whence it now shines down. At first it revolved around the earth at grazing distance. For whole geological epochs its destiny trembled in the balance. Had the speed of rotation been but a fraction of a minute faster than it was, the moon would have crashed back upon the earth. But the complicated mechanism that governed planets and satellites decreed that the moon should slow down just enough to permit the month to exceed the threehour day by a second or two. Thus it became possible for a lunar tidal wave to creep ahead of the moon. The tide applied its frictional brakes, and 54,000,000 years ago the moon began very slowly to spiral away.

“Craters are not uncommon on earth,” says Mr. Kaempffert, “but they bear little resemblance to those of the moon. A lunar crater is not the mouth of a volcano having a diameter of a few hundred feet but a great circular plain, twenty, fifty, even 200 miles in diameter, surrounded by a rampart 5,000 to 10,000 feet high, with a central peak or two about half as high.

“Stand in the middle of one of the larger craters and you can no more see the lofty encircling rampart, lost as it is below a horizon which is nearer than on the earth, than you can see Philadelphia from New York.

“Suppose you could transport your-

a

it self to that world of craters and live. The weird effects of a vacuum would become immediately apparent. Raise your voice in a mighty shout. No echo answers even when one should be expected. Your voice dies in your throat. You are seemingly deaf and dumb. Sound is carried by air, and since there is no air your disabilities are explicable.

“There are no misty landscapes. Every mountain and crater is sharply silhouetted. What artists call aerial perspective is totally lacking, so that it is difficult to gauge distances. Remote mountains seem near, near mountains bewilderingly far. For lack of an atmosphere an airplane would not rise.

“Cast your eyes upward. It is broad daylight, yet the sky is of an inky blackness unknown on earth. The azure of the heavens that we know is but an atmospheric effect produced by the scattering of sunlight by minute particles. And that black lunar canopy is powdered with myriads of stars, despite the glare of the sun—stars that gleam with the piercing, relentless steadiness of electric arcs.

“The earth shines down as the moon beams on the earth. There is a ‘new earth,’ a ‘half earth’ and a ‘full earth,’ with all the intermediate phases. At its full the earth is a gigantic ball four times as large as the moon appears to us. Eighty times brighter than moonlight is this earthlight, because the area of the full earth’s disk is fourteen times greater than that of the full moon. In that lunar night a book can be read with ease. The shadows are softer than by day, and absolute blackness lurks only in the deepest chasms.

“How wondrously the earth is wrapped in its mists! Through rifts the continents and oceans appear and disappear, as if the earth were a colossal illuminated library globe turned by a mighty invisible hand. A sandstorm swirls up in the Desert of Sahara, a tropic typhoon sweeps over the Indian Ocean, verdure waxes and wanes in the Northern and Southern Temperate Zones, the polar caps creep down and recede as snow falls and melts again with the seasons. Never does the changing panorama repeat itself in all its details. Transfixed in the sable sky, the earth neither rises nor sets—a consequence of tidal friction which slowed the moon down so that it always presents the same face.

“And the sun. V/hat a spectacle! No rosy-fingered dawn heralds its rising nor warm parting glow its setting. Yet it is not unannounced. In the east a long pearly veil looms up—the zodiacal light, ten times brighter than we ever behold it on the earth and visible all day long. For hours this false dawn suffuses the sky.

“The sharp knife edge of the solar disk cuts slowly up into the black horizon. For a few minutes the chromosphere appears with its scarlet wreath of incandescent hydrogen, only to vanish and give place to a dazzling glare in which peak after peak juts forth. The shadows are dense, and yet there are half-tones. Because our atmosphere filters out some of its violet and ultra-violet rays, the sun is to us as a white-yellow disk. On the moon it is an electric blue of a hard, blinding intolerable intensity.”