The cold and deathly aspect of our pale satellite was not encouraging for the realisation of the original project of the astronomer J. von Littrow, and soon afterwards, forgetting our nearest neighbour, the imagination of some physicists was bold enough to consider the planet Mars, which is never nearer than 35 million miles, but is the best known of all the countries of the sky and which offers so many points of resemblance with our world that we should hardly feel exiled if we were to transport our household gods thither. The aspect of Mars indeed tends to comfort us after that of the Moon. One could imagine oneself in some terrestrial region. The seasons, summer and winter, autumn and spring, days and night, mornings and evenings, waters, clouds, snows, atmospheric variations, plains adorned with various vegetations—all these things present many resemblances to our own world. The years are longer there since they last 687 days, but the extreme variations of the seasons are about the same as with us since the inclination of the axis is about the same. The days are also a little longer, since the diurnal rotation is 24 hours 37 minutes 23 seconds, but the difference is not great. And you will notice that this is all known with great precision, that diurnal rotation, for example, is known to within one-tenth of a second, or we might even say one-hundredth of a second.
When, on a fine starry night, we examine this world through the telescope, when we see the polar snows which melt in the spring, the finely marked continents, the mediterraneans with long gulfs, the eloquent and varied geographical configuration, one cannot help asking whether the Sun which illuminates that world as it does ours shines on nothing living, whether those rains fertilise anything, whether that atmosphere is breathed by any living being, and whether that world of Mars which rolls swiftly through space resembles a railway train travelling empty without either goods or passengers. The idea that the Earth where we are could swing round the Sun as it does without being inhabited by any creature whatever appears so absurd as to be hardly worth thinking about. By what permanent miracle of sterilisation would the forces of nature which act there as they do here have remained eternally inactive and barren?
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It is therefore conceivable that one might apply to Mars the plan originally proposed for the Moon. The distance of that planet is such that although it is much larger than the Moon in volume, it appears 63 times smaller when it is nearest to us. Yet one may understand that a telescope which magnifies 63 times enlarges Mars to the size of the Moon as seen with the naked eye, and that a magnification of 630 gives it a diameter ten times larger than that of our satellite.
Yet if ever the attempt is made to put any sort of project of communication between us and Mars into practice, the signals would have to be carried out on a much vaster scale. It would not be triangles, squares, circles, of several miles which would have to be constructed, but figures of 70 miles or more, always supposing (1) that Mars is inhabited, (2) that these inhabitants occupy themselves with astronomy, (3) that they have optical instruments analogous to ours, and (4) that they carefully observe our planet, which to them is a brilliant star of the first magnitude, the morning and evening star, and in fact the brightest heavenly body.
Is this fourfold hypothesis acceptable! If that question were put to the vote of the citizens of the Earth, without asking the opinion of the Central African savages or the South Sea Islanders, but only the numerical majority of the European population, one may safely wager that they would not even understand the question, for the majority of mankind does not know that the Earth is a planet and that the other planets are Earths.
And then there is sound common sense which reasons so justly on account of the excellence of its education. “We are,” it says, “without doubt the most intelligent beings of creation. Why should other planets have the honour of being enriched by intellectual excellence such as ours? Can we even admit the existence of beings similar to ourselves?” No doubt one could perhaps remark that the most gifted nations of the Earth do not know how to conduct themselves, that their intelligence is chiefly exercised in devouring each other and in ruining themselves, that they mortgage the future like blind fools, that thieves are not uncommon, nor even murderers. But apart from that we are obviously very superior beings, and it is hardly likely that on any of the myriads of worlds which gravitate in the immensity of space nature should have given birth to intelligences of our calibre.
Why therefore should we attempt an optical correspondence with the planet Mars? If it is inhabited, the inhabitants have not our powers, and our trouble would be thrown away. Even should they see our signals, they would never think that they were meant for them.
Also, we shall never attempt it.
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