LIFE IN OTHER WORLDS?

Evening Star, Issue 21518, 16 September 1933, Page 2

LIFE IN OTHER WORLDS?

OPINION TO-DAY IS OUR EARTH UNIfIUE 7 Half a century ago the question. of the plurality of worlds ” attracted more attention than it does to-day [(writes the astronomical correspondent of the ‘Manchester Guardian’). One reason may be that the leading astronomers who now have the ear of the public are not themselves particularly con-, .cerned; their attitude is either’ agnostic or definitely sceptical. Perhaps Sir James Jeans is the most widely-read writer on astronomy at the present time; and in all his writings, for years past, he has expressed himself as more or less hostile to the belief that intelligent life exists anywhere outside of the earth. In the first instance, Sir James bases his attitude on his own famous “ tidal theory ” of the origin of the solar system. According to this hypothesis, the earth and the other planets were formed as the result of the near approach of two stars in the distant past several billions of years ago. One of these was the primitive sun, and the result of the encounter was that enormous masses of gaseous and molten matter were torn out of the sun by the action of the other star. These masses of matter solidified in the course of ages, and now form the planets. Presumably other planets were torn out of the interior of the other star, but Sir James Jeans has stressed the infrequency of such near encounters among jthe stars even in the faraway past. At the time when h© promulgated the [theory he believed the life of the average star to be 300,000,000 years; and he emphasised the extreme rarity of such approaches, concluding that “ it is just within the bounds of possibility ;that our system is, unique.” The discovery that the age of the stars is to be reckoned in billions rather than in millions of years has, says Jeans, lessened “ the inherent improbability ” of the formation of solar systems as the result of close approaches. Nevertheless he still holds to the view that solar systems must be relatively rare in the ■universe, and that perhaps in only one of these systems is there a planet on .which life of a high order can exist. In any case, Sir James makes it evident that the plurality of worlds does not particularly interest him. Recently doubts have been expressed by prominent astronomers as to the validity of Sir James Jeans’s idea that solar systems could only be formed in one way. Professor Sampson, Astronomer Royal for Scotland, and Dr Jaokson, now His Majesty’s astronomer at the Cape, have shown that there are other possible modes of origin. Planets, they maintain, may originate either as ■“ drops ” of matter loft over when a star divides into two, or by cosmic material forming condensations in the primeval chaos and becoming attached to larger condensations. THE PLANETS. Leaving aside the possibility of the existence of other ‘ solar systems, it may be asked: What about the planets in our own system? : Sir James Jeans rules out the possibility of anything approaching intelligent life on any of our neighbour worlds." In the case of the four planetary giants, Jupiter, Saturn, Uranus, and Neptune, there will be general agreement with his ruling. There are two plausible explanations of the low densities of these planets. One is that they are in a much more primitive state than our earth, and intensely hob inside; the other that they are very cold but composed of lighter materials with which yro are unacquainted. The former and older hypothesis seems to the present .writer to he the more probable; but, whichever is true, it would seem that 'Jupiter and its fellow-giants are quite ■uninhabitable. If life exists on any world in the solar system outside of our own, that world must be within the zone of the asteroids. The earth has three-feltow-dwarfs— Mercury, Venus, and Mars. Of these, Mercury may be left out of account. Wo know little of that planet, but what we do know suggests the inherent improbability of any high forms of life there. It seems to be more or less a dead world, similar to the moon, and the very high temperature resulting from its proximity to the sun would seem to rule it out altogether. Venus is different. Hero is a world similar to the earth in many respects, of which, owing to the cloud-laden atmosphere which envelops it, we know far too little to make any dogmatic pronouncements for or against its habitability. 'Astronomers are now studying Venus indirectly by means of photography in light of various colours, and new facts may be ascertained which will enable us to pronounce for or against. THE “CANALS” OF MARS. Percival Lowell was the chief protagonist of the view that Mars is inhabited, Since his death only one definite • advance in our knowledge of Mars has been registered, but it strengthens rather than weakens Lowell’s views. The temperature of Mars was measured at two successive approaches of the planet by the astronomers at the Lowell and Mount Wilson Observatories, and lias been shown to be cpiite high enough, in the equatorial legions ab least, for the existence not only of vegetable, but of animal life. As to the Lowellian theory that the Kals are the handiwork of intelligent kgs, it has never been disproved, tad I* dismiss it in a somewhat cavalier

manner is not scientific. Even if Lowell should prove to have been wrong there may well be intelligent life on Mars. Certainly Mars is no dead world. An appreciable atmosphere, of which oxygen and water-vapour are constituents, snow and ice, rain, dew, hoar-frost, temporary seas and marshes, and vegetable life in plenty—these are not marks of a dead world. Professor W, H. Pickering is perhaps tho chief authority to-day on Mars, and his reasoned conclusion reached a few years ago is that “ animal life may readily exist in Mars. Indeed, a possibility exists that even human life, if transported to Mars, might exist and flourish there.”