LIFE ON OTHER PLANETS

Greymouth Evening Star, 26 April 1938, Page 10

LIFE ON OTHER PLANETS

.XSTKOXOJIERS VIEWS lii his book, "Frontiers of Science," Up. Carl Trueblood Chase. ol the New York I 'nive.rsity. has sunimaris•id the progress made and the present posit ioii in astronomy. physics, bio•ology. and other fundaniciital sciences. One of iln- questions with which lie •|< ;,is is whether there are, in the universe. any other inhabited worlds, says N. M. Goddard in the Sydney ’Morning Herald." Dr. Chase shows that at present there is no direct evidence of life beyond ike earth, but that there is reason to believe that Mars may he innabitetl. although if. in the course of ;ime.. the earth became too cold to support life. Venns would be the most likely place to provide, a new home for mankind. Mars is even now cooler than the earth, and. when the earth becomes too cold, it would lie useless.

It would appear to be a simple matter to find out if there is any life on •he nearer planets of the solar system by building telescopes of greater magnifying power until a sufficiently detailed view of the surface of tlieplanet is obtained. There are two reasons, however, why this plan cannot .succeed. One is the atmosphere of Die earth, which, with its currents •and hot and cold patches binds ami distorts the incoming light rays so 'hat. only a blurred impression can he obtained. The other is the atmosphere. on flic planet under observation, which would have a similar effect, and the planet must have an atmosphere if life according to the earthly standards is t" exist thereon. In the absence of a direct means of attack on the problem, astronomers n.ml physicists are compelled Io endeavour to find out whether the physical couditif.m of the surface of the. planet is sm.-h that life could he supported. Given this information, biologists can say what forms of life could exist and whether primitive forms of vegetable and animal life could develop under such conditions info higher forms. Astronomers have made some progress in their part, of the problem, but biologists have some large gaps to HU in. For example, they are not able to say that life will inevitably arise whenever ami wherever conditions are favourable.

SIMILARITY TO THE EARTH In researches of flii>-'sort the investigators can only.-Took for conditions which will .support life of the same kind as that which exists on earth. The general s.ojid structure of a planet, it is safe to ; assume, is the same as that of earth, because all tlie planets bad. .ap,common origin in the sun, and it fiFkiibwii that the sun contains the elements that are found in the earth. , , The main requirements are that" must receive sunlight irr reasonable quantifies. must have a moderate temperature. and an atmosphere which contains oxygen and carbon' dioxide, and also water vapour as an indication that there is water on the planet. If all these are found, life may exist. If not, life as is known on earth does ! not exist. I It is not a difficult matter to tell whether a. planet has an atmospliere I or not. Unless it has sufficient mass, I it. cannot hold its atmosphere, if ever j it had one. The mass of the moon, I for example, is so small that its gra-i vitational attraction could not hold a eas for long. For the same reason. I Mercury, the planet nearest the sun. | can have no atmosphere, nor can the small planetoids which travel in orbits between those of Mars and Jupiter. On both Venus and Mars, atnios-

plieres have been detected, and because i hey are comparable in size with the earth, and are also not Lot.' close to nor too far from the sun, they are considered to be the most likely places tor life exist, outside the earth. They are. except for Die moon ami a few planetoids, the earth’s nearest nc.igii hours. The surface of Venus has never l.'t.eii set in because the planet is always shrouded in cloud. Strenuous efforts have been made to penetrate, this protecting shield by means of ultra-violet and infra-red photography, and oilier means, but still it holds it.s sercets. It has not yet been determined with certainty what it.s period of rotation is. nor is it certain that it has oxygen or water vapour, at any rate in its upper atmosphere. It maybe tlrnt the oxygen is at lower impenetrated levels, and that in the upper visible parts of its cloud layers the water vapour is in the form of fine crystals of ice.

There is evidence, as yet unconfirmed. of the presence of carbon, dioxide in its atmosphere. If this is so. it is likely that there is plant life on the planet, and possibly animal life. Temperature conditions are suitable cm its surface because of the protective effete of the layers of clouds. The stumbling blocks arc Ihe inconclusive evidence of the presence of oxygen or carbon dioxide. MARS AND OTHER PLANETS Mars presents apparently a much better case lor the presence of life. Smaller and less dense than i he earth, rotating once in a. little more than 24 hours, it. has a clear atmosphere, which contains both, oxygen and water vapour hm both in smaller quantities than our atmosphere. Certain cd its prominent surface features are visible, white polar ice caps, arc, as of a reddish lute, and other areas that change wiil> the seasons, and certain streaks and line-:, which the optimistic Lowell holds to bn irrigation canals. This view, however, is disputed by many observers. There are no oceans or large kikes. The temperature on the illuminated side is moderate, but cm the. dark or ’‘night." side, j ii is always well below freezing point, j These are mil the best conditions for j plant life, bin there, arc types that , could exist. Human life could possibly exist, but the. best opinions allow that only some forms of low forms of vegetables and, possibly, animal life exist.

The other planets. Jupiter. Saturn. Uranus, Neptune, ami Pluto are so far from the sun that, they are extremely cold, and have never been considered as habitable by our standards. and, at this stage, it is .only possible to guess that th re is life on any planetary system that may be attached to other stars. Future research may throw light on this question.