LIFE ON DISTANT WORLDS.

Dunstan Times, Issue 2676, 28 July 1913, Page 2

LIFE ON DISTANT WORLDS.

The possibility of the heavenly bodies being inhabited by living beings resembling ourselves, was a question that much exercised the learned in the last century, and has been revived lately by the veteran biologist Sir Alfred Wallace, and by the eminent astronomer Mr Walter Maunder. Like all scientific problems of wide scope, it has always had its metaphysical side, and even in the latest utterances on the subject, the religious prepossessions of those who have discussed it have been a good deal in evidence. Mr Maunder, who bias just published a very readable little book dealing with the point, is of opinion that neither the Sun nor the Moon, nor any of the planetary bodies save our Earth and possibly one other, can be inhabited, because they are all either too hot or too cold to support life. Thus the Sun has, by direct observation, a temperature of over 5000 deg. 0.; while the Moon, owing to its absence of atmosphere, must at night be at about the temperature of liquid air. Of the planets nearer the Sun than ourselves. Mercury always turns the same face towards the centre of our system, and that side of it must, therefore, be hotter than anything of which we have any experience; while tlx© other side must b© not only in perpetual darkness, but exposed to great cold. Mars, thanks to various causes, must everywhere have a temperature below 0 deg. C., while the more distant planets—Jupiter, Saturn, Uranus, and Neptune —if they depended on the Sun’s heat alone, would be frozen through and through. As it is, the internal heat due to their vast bulk compared with our own earth has kept them in the nearly incandescent condition of “semi-Suns,” and, according to Mr Maunder, has probahlv prevented them from having any solid, nucleus at all. As protoplasm, the universal constituent of all living matter, can only retain its qualities at temperatures between 0 deg. C. and 100 deg. C., it follows that no life in the form known to us can exist on anv of these spheres. There remains Venus, which chould have a mean temperature of 69 cleg. 0., and an equatorial one of 95 deg. C., so that, if the I difference in pressure is considered, water should boil at its equator. . This, however, would lead to its upper atmosphere consisting largely of clouds of steam, and these would in turn cut off a great quantity of the Sun’s heat. It is probable, however, that Venus, like Mercury, always presents the same face to the sun; but as this has not yet been fully observed, Mr Maunder reserves judgment as to her possible habitability. But, save for this, he does not see how life can exist on any of the planets but ours. Had he made this pronouncement Papaliter, his authority on such matters is deservedly so great that many of us might have been inclined to accept it without question. But as he has rightly preferred to disregard the advice once offered by a learned judge, and to give reasons for his conclusion, it must needs be said Mmt these seem hardly without flaw. It is. doubtless, the case that our terrestrial protoplasm could not exist at the temperatures which he assign® to the sun, moon, and planets; but protoplasm is an extraordinarily complex substance, and we are hardly justified in concluding that its constitution must everywhere be the same. As we know it. it consists of carbon, hydrogen, nitrogron, and oxygen, with a trace of sulphur and. perhaps, of phosphorus. But. these, like all the so-called “elements,” bear numerical relations to ©aHi other which have not yet been fully explored, and! there is much reason for thinking that they may all have proceeded, at some long-distant period, from some sort of primitive matter, protyle. or “ur-stoff.” Moreover, there are at least a few elements perceptible bv the spectroscope in the heavenly bodies, such as nebnlium and ooroniura, which haye, so far, no known counterparts on earth. It is conceivable, then, that out of such unknown materials, there might be built up under other than terrestrial conditions, a protoplasm that, although differing from ours, would answer all the purpose of a chemical basis of life. Moreover, if we conclude that none of the planets but ours is fit for habitation. wo do but push the question a little further back. The centre of our system is what a, wittv Frenchman once described as the 7,344,746 th yellow sun, and although it may not occupy such an insignificant place in the sky ms this imposing figure would imply, it is id ain that there are among the stars a. great number of other suns all surrounded by planets, some of which may be in a condition as well fitted as onr earth for the maintenance of 1 ife. Hence, however flattering to onr vanity the geocentric and anthropocentric ideas of the learned men above quoted may bo, wo must not lose sight of the fact that there is another side to the picture.