Conversations on the Plurality of Worlds

by M. de Fontenelle

[45] Venus is not farther from Jupiter, but more concealed by the rays of the sun.

What! cried the Marchioness; do you consider it a kindness? Without doubt, answered I. This great vortex contains sixteen planets; nature to spare us the trouble of studying the motions of so many, let us see but seven: is not that a favour? But not feeling the value of this mark of consideration, we have, with great pains, discovered the other nine, which had been concealed from us: our curiosity brings its own punishment in the laborious study which astronomy now requires.

I see, she replied, by the number of planets you mention, that Saturn must have five moons.[46] You are right, said I; and it is but just that he should have so many, as he is thirty years in going round the sun; and in some parts the nights last fifteen years, for the same reason that on our globe, which turns in a year, there are nights, beneath the poles of six months' duration. But Saturn, being at twice the distance that Jupiter is from the sun, consequently ten times farther than the earth; his five moons, faintly as they are illumined, would not give sufficient light during his nights, he has therefore a wonderful resource, the only one of the kind we have discovered in the universe: 'tis a large circle or ring[47] which environs the planet, and which, being sufficiently elevated to escape almost entirely the shadow of Saturn, reflects the sun's light on the darkened parts, and reflects it more strongly than all the five moons, because it is not so high as the lowest of them.

[46] He has seven, and Herschel six. In all there are twenty-five planets, without reckoning ninety-one comets known in 1800.

[47] Its exterior diameter is sixty seven thousand seven hundred leagues.

Really, said the Marchioness, with an air of deep reflection and astonishment, all this is managed with wonderful order; nature had certainly in these instances a view to the wants of living beings; this admirable disposition of light was not the effect of chance. Only the planets which are distant from the sun have been provided with moons—the Earth, Jupiter, and Saturn; for Venus did not require any; nor Mercury who already has too much light; whose nights are extremely short, and probably considered a greater blessing than even the days. But stop—I think Mars, who is farther from the sun than we, is without a moon. We cannot conceal the fact, I replied; he has none; but he doubtless has resources for the night which we are ignorant of. You have seen phosphorus; matters of that kind, whether liquid or dry, receive and imbibe the light from the sun, which they emit with some force when in the dark. Mars perhaps has high rocks of phosphorus that absorb, in the day-time, light enough to irradiate the night. You must own it would be an agreeable sight for the rocks to light up as soon as the sun was set, and without art, produce the most magnificent illuminations, that with all their radiance, would not have the inconvenience of casting any heat. In America, you know, there are birds which in the dark will afford light enough to read by: how can we tell whether Mars has not a great number of such birds, who, as soon as the night is come, disperse themselves on every side, and give an artificial day?

I am not satisfied, answered she, either with your rocks or birds. They would be pretty enough to be sure; but as nature has bestowed so many moons on Saturn and Jupiter, it shews that moons are necessary. I should have been very much pleased to find that all the worlds at a great distance from the sun had some, if Mars had not formed a disagreeable exception. Ah! replied I, if you were more deeply versed in philosophy you must accustom yourself to see exceptions to the best systems. We clearly see that some things are adapted in the most perfect manner to their end; others we accommodate as well as we can, or perhaps are obliged to content ourselves with knowing nothing about them. Let us do so with respect to Mars, since our researches are fruitless, and resolve to say no more about him.

We should be very much surprised, were we on Saturn, to see during the night a great ring, extending over our heads in a semi-circular form from one end of the horizon to the other; and by reflecting the light of the sun, would have the effect of a moon at every part of the circle. And are we not to have inhabitants in this great ring? said she, laughing. Though I am disposed to place them wherever I can, answered I, I confess I dare not tell you there are any there; this ring appears too irregular a dwelling. As for the five moons, we can't dispense with inhabitants for them. If the ring, however, were what some suppose, only a circle of moons, following each other very closely, with an equal motion, and the satellites, five of these moons escaped out of the ring, what numbers of worlds would the vortex of Saturn contain! Be that as it may, the people in Saturn are uncomfortable enough, even with the help of their ring. It gives then light, it is true; but what sort of light, at that immense distance from the sun? The sun himself, which appears to them a hundred times smaller[48] than to us, seems but a little pale star, emitting but a feeble light or heat. And could they be transported to our coldest countries, such as Greenland and Lapland, you would see them ready to expire with the heat. If water were conveyed to their planet it would no longer be water, but a polished stone, and spirits of wine which never freeze here, would become hard as diamond.

[48] Ten times less in diameter.

Your description of Saturn petrifies me, said the Marchioness; though just now you almost threw me into a fever in talking of Mercury. Two worlds, answered I, which are at the different extremities of an immense vortex, must be totally unlike.