Thus we see that Mars is the most like earth of all the planets, and its inhabitants—if, indeed, it is now inhabited—must have a beautiful view of us when the weather is fine, for we are so much larger. Mars is also attended by two satellites, or moons, as Professor Hall reported from Washington in 1877. These moons have been named Deimos and Phobos, and are both very small, their diameter being only about six miles; but late astronomers have reasoned that they must be three times this diameter.
Fig. 582.—Earth seen from Mars.
There have been numerous theories concerning Mars being inhabited, and of course these suggestions made respecting life on one planet may, with varying circumstances, be applied to another. Each planet may have had, or may yet have, to pass through what has been termed a “life-bearing stage.” We on earth are at present in the enjoyment of that stage. So far as we can tell, therefore, Mars may be inhabited now, as he bears much the same appearance as our planet. Certain changes are going on in Mars, and all planets, just as they go on here in our earth, and as they did long, long ages before the earth was populated, and which will continue to go on after life on the earth has ceased to exist.
Mars is, as we know, much further away from the sun than earth is, and must receive less direct heat. When he was created, or formed, we can only conjecture, but in all probability he cooled before the earth did, as he is smaller. Here another theory concerning the state of Mars arises, and in support of it we may quote an American authority upon the planet.
“His mass is not much more than one-ninth of the earth’s, while his surface is about one-third of hers. Then, if originally formed of the same temperature, he had only one-ninth her amount of heat to distribute. If he had radiated it away at one-ninth of her rate, his supply would have lasted as long, but radiation takes place from the surface in proportion to the surface, hence he parted with it three times as fast as he should have done to cool at the same rate as the earth, and must have attained a condition which she will not attain until three times as long an interval has elapsed from the era of her first existence than has already elapsed. Geologists agree that the last-named period must be measured by many millions of years; hence it follows that twice as many millions of years must elapse before our earth will be in the same condition as Mars, and Mars must be three times as far on the way toward planetary decrepitude and death as our earth. Then assigning two hundred thousand years as the extreme duration of the period during which men capable of studying the problems of the universe have existed, and will exist on this earth, the theory holds that Mars would have entered on that stage of his existence many millions of years ago, and that the appearance of the planet itself implies a much later stage of planetary existence.”
Mars is a very interesting study, and the reddish hue which is so distinctive is perceived in certain spots when examined by the telescope’s aid. These red places were discovered by Cassini. Mr. Dawes made drawings of Mars, and Mr. Proctor has by their aid constructed a regular map of Mars, and a chart of the surface of the planet. There is much more land than water on Mars, as the bright surfaces which indicate land are much more extensive than the darker portions which betoken the existence of water. But these “markings” are not always visible, in consequence of something coming between us and the land on Mars, and this has been attributed to the production of vegetation, which a French savant declared was ruddy-coloured, and that this autumnal tint departed in the winter.
The seasons of Mars are not equal, in consequence of his wandering propensities, and winter is warmer up there than our winter, while summer is cooler than our summer. That there are clouds and an aqueous atmosphere surrounding Mars we learn from spectroscopic observation and analysis, and in fine we may look upon Mars as similar to our earth. Respecting the question of its habitation we take the liberty to quote Mr. Richard Proctor:—
“I fear my own conclusion about Mars is that his present condition is very desolate. I look on the ruddiness of tint to which I have referred as one of the signs that the planet of war has long since passed its prime. There are lands and seas in Mars, the vapour of water is present in his air, clouds form, rains and snows fall upon his surface, and doubtless brooks and rivers irrigate his soil, and carry down the moisture collected on his wide continents to the seas whence the clouds had originally been formed. But I do not think there is much vegetation on Mars, or that many living creatures of the higher types of Martian life as it once existed still remain. All that is known about the planet tends to show that the time when it attained that stage of planetary existence through which our earth is now passing must be set millions of years, perhaps hundreds of millions of years ago. He has not yet, indeed, reached that airless and waterless condition, that extremity of internal cold, or in fact that utter unfitness to support any kind of life, which would seem to prevail in the moon. The planet of war in some respects resembles a desolate battle-field, and I fancy that there is not a single region of the earth now inhabited by man which is not infinitely more comfortable as an abode of life than the most favoured regions of Mars at the present time would be for creatures like ourselves.”
