HOW WORLD MAY END

Evening Star, Issue 22805, 13 November 1937, Page 13

HOW WORLD MAY END

HIT-AND-RUN STAR MAY STRIKE IT RADIUM AND ENERGY How the world will come to an end is a favourite subject for speculation oven among scientists.' This catastrophe is well within the realm of scientific possibility, given sufficient time. A preview of several possible “ ends of the world ” has been worked out by the scientific staff of the Hayden Planetarium at the American Museum of Natural History, and the public is having an opportunity to experience this thrill with a non-fatal termination (writes Professor W. H. Barton, in ’The Sky’). HOW END MAY COME.

Among the possible events which may bring about the end of the world, and which have been dramatised at the planetarium are: (1) 'Two stars side-swiping each other depict how our solar system might be smashed by a hit-and-run star. (2) What would happen if the earth collided with a comet is shown in a crash between our globe and Donati’s comet, ns scon from space. (;i) The possibility that the sun might become a nova, or “ exploding star,” and burn tho earth to a crisp, or else become so cool and faint that the earth would freeze, is also brought to light. , (4) The most impressive spectacle of all is the destruction of the moon by earth’s gravity pull and tho moon’s eventual transformation into a ring like that which now encircles Saturn. DEPENDENT ON SUN. “ Tho condition of our own planet is so dependent on the condition of the sun that wo must consider it tho controlling factor in our life story,” writes Professor Barton. “ The sun is a star, an average star, and in the night sky are millions of other stars —other suns. “ The suns that we call the stars of the night sky are great globes of glowing masses. They are so hot that heavy metals are not solids, but vapours. From tho surfaces of the stars energy is constantly pouring out into space, recklessly distributed to the universe. How can a star afford to so recklessly spend its life blood? It cannot without suffering irreparable loss. , “ Where does the star acquire the energy it sends out and how can it store it? The answer to that has changed. Once it was thought that our sun (typical of other stars) obtained its heat by contracting. This was called the Helmholz contraction theory. Figuring backward into the sun’s past indicated a shorter life for our earth than the- geologist was willing to admit. Looking forward was rather discouraging—only a few million years and the earth would be a planet to a dead, cold sun! The oceans would freeze. The day would be dark, and life would be a thing of the past.” COMING OF RADIUM. Such dead, dark stars are not found merely in the imaginations of those who think about one thing too much, but they are real, says Professor Barton. He points out that there are in the sky a family of small, shrunken, and shrivelled dwarfs—dead suns with a past but without a future. “ Then came something new—radium and other similar radio-active substances—material that sent out rays of energy of its own accord,” Professor Barton says. “ Day after day, year after year, its material seemed to, be changing into energy. So much_ energy came with so little loss of material that it seemed unreal. Perhaps that was what the sun was doing, had been doing for more years than suited _ the contraction theory, and would continue to do beyond the expectations of the gloomy prophets. The sun bad taken a new lease of life! The_ evil day had been put off. But that is all—it had been put off. No matter how massive the sun was, some day it will change its last atom into energy, and eight minutes later the earth will receive its last crumb and the cupboard would be bare. But that is billions of years in the future. EACH STAR IS DYING.

" In the same way each, star in our sky is slowly dying. Are new worlds recreated out of the dehrig of old ones? There are no answers to those questions. Perhaps the mysterious cosmic rays are a factor in the problem. They have been called the death rattle of dying stars.” Can anything else happen? Yes, say the astronomers. Every now and again a star fs seen suddenly to blaze up in an alarming manner. In a few days, or even in a few hours, this sudden outpouring of energy may make a star hundreds of times brighter than it was before. “ Such an outburst from our sun Would sear our earth’s crust to a cinder, turn the oceans into boiling cauldrons, and leave no traco of higher life,” Professor Barton says. Another possibility, ho adds, is believed really to have occurred to our sun—that is, either the near approach to or the actual collision with another star.

“ Our solar system may have had its origin in such a collision knocking pieces off the sun, while the star that intruded the privacy of the sun went its way as nonchalantly as a passer-by in a jostling holiday crowd. COMET’S PELTING METEORS. 11 It is conceivable that a comot might come dangerously close to the earth—or even hit it. The pelting meteors from space, even if most of them do not strike the earth’s surface, become a part of it by adding their weight. They increase the mass of the earth. This planet has just so much energy in it to keep it spinning like a top. Increase the amount of material in the globe, and its speed of rotation slows down; tho day gets longer, and our relations with the moon are disturbed. The moon itself contributes to tins running down of our earth clock. Twice each day the ocean waters rise and fall in a tidal pulsation. While the sun contributes its small part, the moon is the principal factor. While the moon causes this disturbance, the bill is paid by the earth itself. The moving of such a great quantity of water in tho seas makes friction, and that means heat, and that takes energy. The earth supplies this from its limited store, so while the mass is increasing, the power to spin it becomes less and less.” The reaction on tho moon is to make it go farther from, tho earth, and consequently to make its period of revolution around the earth longer. Just as in tho slowing down of the earth we risked falling into the sun, so slowing down the moon tends to make it fall into the earth. This .would tend to break it up. “ Bui, meantime, what of the earth? The same unleashed forces that destroyed the moon would disrupt the earth. Volcanoes would open to spill and spit out the molten core of our globe, earthquakes would shake the solid ground, levelling mountains to ocean floors and raising new continents that would be nameless for want of those who name things.’-!