Well, on Venus, apparently, these very conditions actually exist. How, then, do intellectual creatures in the world of Venus take wing when they choose? Upon what spectacle of fluttering pinions afloat in iridescent air, like a Raphael dream of heaven and its angels, might we not look down if we could get near enough to our brilliant evening star to behold the intimate splendors of its life?
As Venus herself would be the most brilliant member of the celestial host to an observer stationed on the night side of Mercury, so the earth takes precedence in the midnight sky of Venus. For the inhabitants of Venus Mercury is a splendid evening and morning star only, while the earth, being an outer planet, is visible at times in that part of the sky which is directly opposite to the place of the sun. The light reflected from our planet is probably less dazzling than that which Venus sends to us, both because, at our greater distance, the sunlight is less intense, and because our rarer atmosphere reflects a smaller proportion of the rays incident upon it. But the earth is, after all, a more brilliant phenomenon seen from Venus than the latter is seen from the earth, for the reason that the entire illuminated disk of the earth is presented toward our sister planet when the two are at their nearest point of approach, whereas, at that time, the larger part of the surface of Venus that is turned earthward has no illumination, while the illuminated portion is a mere crescent.
Owing, again, to the comparative rarity of the terrestrial atmosphere, it is probable that the inhabitants of Venus--assuming their existence--enjoy a superb view of the continents, oceans, polar snows, and passing clouds that color and variegate the face of the earth. Our astronomers can study the full disk of Venus only when she is at her greatest distance, and on the opposite side of the sun from us, where she is half concealed in the glare. The astronomers of Venus, on the other hand, can study the earth under the most favorable conditions of observation--that is to say, when it is nearest to them and when, being in opposition to the sun, its whole disk is fully illuminated. In fact, there is no planet in the entire system which enjoys an outlook toward a sister world comparable with that which Venus enjoys with regard to the earth. If there be astronomers upon Venus, armed with telescopes, it is safe to guess that they possess a knowledge of the surface of the earth far exceeding in minuteness and accuracy the knowledge that we possess of the features of any heavenly body except the moon. They must long ago have been able to form definite conclusions concerning the meteorology and the probable habitability of our planet.