Chambers's Journal of Popular Literature, Science, and Art, fifth series, no. 128, vol. III, June 12, 1886

No. 128.—Vol. III.
Price 1½ d.
SATURDAY, JUNE 12, 1886.
The question as to the habitability of other worlds than ours has always been a very fascinating one, and, indeed, it is not surprising that it is so; for since the days when the earth was debased from her proud position as centre of the universe, and was assigned her proper place among the planets, there seemed to be no particular reason why she alone should produce life, and why other planets, apparently as suitable for this purpose as she is, should wander uninhabited through space.
Up to the present time, it must be confessed, we have met with nothing but disappointment in this branch of inquiry; for not only have we not detected living creatures on any other member of the solar system, but, with the single exception we are considering, there is apparently no other body whose surface is under conditions which would lead us to suppose that it might support life, or at least life in any form with which we are acquainted. It is of course useless to argue about the possibility of life under entirely different conditions; for instance, there might be some form of life on the sun; we can only say that it would be so different from what we know as life, that the term would be hardly applicable; and whether it is likely to exist or not, is a question which our limited experience does not allow us to answer one way or the other.
The moon, again, may be the home of living creatures; but they must be so constituted as to exist without air of any sort, which is rather contrary to our notions of life.
We will not here go to the length of examining in detail the conditions which obtain on the surface of all the bodies within range of our telescopes; but we may state that in none of them, with the exception of the planet Mars, is there any resemblance to our earth, and therefore life as we know it could not exist on them. With Mars, the case is different, and at first sight, there appears to be a state of things which approximates closely to that which obtains here. The planet Mars appears to the naked eye a deep red colour, and when examined with the telescope, we see that a large part of his surface is red; but between the red, and intersecting it in all directions, are patches and strips of a dull greenish hue. It was very soon conjectured that this green part was the Martial sea, and that the red was the land: this has been confirmed by later observations, and now no doubt exists on the point. The principal problem that we are here confronted with is this: assuming that what appears green on Mars is a liquid of some sort, can we assume that it is water, and not some other liquid with which perhaps we are unacquainted? This question appears at first sight impossible; for, unless we can bring some of the Martial sea down to the earth and analyse it, how can we determine its chemical constitution? The telescope evidently will not help us here, and we must call to our aid that powerful ally of the telescope—the spectroscope.