Parasite Planet

Luckily for "Ham" Hammond it was mid-winter when the mudspout came. Mid-winter, that is, in the Venusian sense, which is nothing at all like the conception of the season generally entertained on Earth, except possibly, by dwellers in the hotter regions of the Amazon basin, or the Congo. They, perhaps, might form a vague mental picture of winter on Venus by visualizing their hottest summer days, multiplying the heat, discomfort and unpleasant denizens of the jungle by ten or twelve. On Venus, as is now well known, the seasons occur alternately in opposite hemispheres, as on the Earth, but with a very important difference. Here, when North America and Europe swelter in summer, it is winter in Australia and Cape Colony and Argentina. It is the northern and southern hemispheres which alternate their seasons. But on Venus, very strangely, it is the eastern and western hemispheres, because the seasons of Venus depend, not on inclination to the plane of the ecliptic, but on libration. Venus does not rotate, but keeps the same face always toward the Sun, just as the Moon does toward the earth. One face is forever daylight, and the other forever night, and only along the twilight zone, a strip five hundred miles wide, is human habitation possible, a thin ring of territory circling the planet.