Conversations on the Plurality of Worlds

by M. de Fontenelle

The Marchioness wished to pursue our astronomical researches during the day; but I told her that as the moon and stars were the subjects of our whimsical conversations, they ought to be our only confidants; we therefore waited till evening, and then took our usual ramble in the park, which thus became sacred to learning.

I have a vast deal of news to tell you, said I; I yesterday told you that the moon, according to all appearances, was inhabited; but I have recollected a circumstance which would expose its inhabitants to so much danger, that I don't know whether I shall not retract my former opinion. Indeed I will not suffer you to retract it, answered she. Yesterday you prepared me to receive a visit from the inhabitants of the moon, in a few days; now you are going to refuse them a place in the creation. You shall not trifle with me in this way. You told me the moon was inhabited; I surmounted the difficulty of believing it, and now I will continue to believe it. Softly! said I; we should give but half an assent to an opinion of this nature, and reserve the other half in case we should find the opposite idea better supported. I am not contented with words, she replied; give me facts: remember your comparison of the moon with St. Dennis. But, answered I, the moon is not so similar to the earth as St. Dennis is to Paris. The sun draws out of the earth and water exhalations, which rise to a certain height in the air, collect together, and form themselves into clouds. These clouds hover about the earth in irregular shapes, sometimes shadowing one part, and sometimes another. In viewing the earth from a distance, the appearance of its surface would continually vary, because a large space of country darkened by a cloud would appear less luminous than the other parts, and as the cloud dispersed, would resume its brightness: from this cause the spots on the earth would be seen to change their places, assume different forms, and sometimes be entirely dissipated. If, then, the moon had clouds in its atmosphere, we should observe this variety of spots; but we find them always confined to the same place, which proves that the sun raises no vapours from the moon. It is then a body incomparably more solid than the earth, and its more subtile particles easily dissipated as soon as they are put in motion by the heat. The moon, therefore must be a mass of rock and marble from which no evaporation proceeds; for exhalations so naturally arise where there is water, that we cannot admit the existence of water where they are not found. What sort of beings do you think could inhabit these barren rocks; this country without water? Ah! cried she, you forget that you have assured me the seas in the moon were distinguishable. It was a mere conjecture,[26] I replied; I am sorry to have led you astray. These dark places that have been taken for seas are probably only deep cavities: at so great a distance it is excusable if we don't always guess aright. But, said she, will your objections oblige us to conclude that the moon has no inhabitants? By no means, answered I, we will neither decide one way or the other. I must own my weakness, she replied; I cannot bear to remain in suspense. I must believe something: enable me to determine; let us ascertain the existence of these people, or let us annihilate them at once, and think no more about them. But preserve them if possible; I have formed an attachment for them, of which I shall not easily divest myself. I will not leave the moon without inhabitants then, said I; for your pleasure it shall be repeopled.

[26] This is not, now, even conjectured, for with a telescope we may see irregularities at the bottom of what were supposed to be seas.

As the spots in the moon never vary,[27] we certainly, cannot believe that there are any surrounding clouds which successively obscure the surrounding parts; this however is not a proof that there are no exhalations; our clouds are formed of vapours, which at their first rising out of the earth, were in separate particles, too small to be visible to us; in ascending they meet with a degree of cold that condenses, and unites them into conspicuous forms; after which they float in the air till they dissolve in rain. But these exhalations frequently remain dispersed and imperceptible, and fall back on the ground in gentle dews. I suppose then that vapours of this kind are exhaled from the moon, for it is incredible that the moon should be a large mass, composed of parts all equally solid, all in a state of equal tranquillity, all incapable of being influenced by the action of the sun. We know of no body which has these properties, not even marble. The most dense bodies are subject to change, either from some secret and interior motion, or from the action of external matter. As the exhalations from the moon, do not form themselves into clouds, and return in showers, they can only become dew; for that purpose it is not necessary that the atmosphere, which apparently adheres to the moon as ours does to the earth, should be exactly similar to our air, nor the vapours exactly like ours; and that I think is probably the case:[28] the matter must have a different disposition in the moon, from that in the earth; consequently the effects be different; however all that is of no importance; since we find that there is motion in the parts of the moon, either internal, or produced by foreign causes, we may again people it, as we have the means of affording them subsistence; of producing fruit, corn, water, and every thing that is needful. I mean fruit, corn, &c. such as the moon can produce, the nature of which I am unacquainted with; and all these in proportion to the wants of its inhabitants, of which I am likewise ignorant.

[27] M. Herschel has observed variations in them; which he, with certainty, attributes to the industry of the inhabitants.

[28] The atmosphere of the moon, if there be any, is quite invisible to us.

That is to say, answered the Marchioness, you are sure every thing is right, without knowing how it is; here is a little knowledge placed against a great deal of ignorance, but we must be content with it: I am very happy to have inhabitants restored to the moon; I am glad also that you give them a surrounding atmosphere, for it seems to me that a planet would be too naked without one.

These two different airs, said I, one belonging to the earth, the other to the moon, tend to prevent the communication between the two planets. If it merely depended on the power of flying, who knows, as I yesterday said, but we may at some future time be sufficiently expert? All things considered, I think we must not expect this communication; the amazing distance at which they are placed, would be a considerable difficulty; and were this obstacle removed; were the two planets nearer together, it would be impossible to pass from one atmosphere to the other. Water is the atmosphere of fishes; they never pass into that of birds, nor the birds into theirs: they are not prevented by the distance, but the existence of both depends on their proper element. Our air, we find, is mixed with more dense and gross vapours than that of the moon; therefore an inhabitant of that world would be drowned if he entered our atmosphere, and fall lifeless on the earth.

Oh! how glad I should be, exclaimed the Marchioness, for a shipwreck to cast a good number of them on the earth, we might then examine them at our leisure. But, I replied, if they were clever enough to navigate the surface of our atmosphere, and from a curiosity to examine us, should be tempted to draw us up like fishes; would that please you? Why not? answered she, laughing. I would voluntarily put myself in their nets, just for the pleasure of seeing the fishers.

Remember, said I, you would be very ill by the time you reached the top of our air; we are not capable of breathing it above a certain height;[29] it is said that at the summit of some mountains we can scarcely do it. I wonder that people who are silly enough to believe that corporeal genii inhabit the purest regions of the air, should not tell us, as the reason for our receiving such short and unfrequent visits from these genii, that few of them understand diving, and even those who excel in it cannot remain long in our gross air.