National Geographic : 1939 Jul
THE NATIONAL GEOGRAPHIC MAGAZINE C) National Geographic Society fainting by Lharles iiittinger, IN. A. THE ONLY LIFE OUTSIDE THE EARTH MAY EXIST IN MARS' GREEN PATCHES Many astronomers think they are some form of vegetation, for they appear and disappear with the changing Martian seasons. The planet is seen here from Phobos, the nearer of its two moons. Spring prevails on the upper half of the globe, so the white polar ice cap has shrunk considerably. At lower right are some of the famous "canals." Vast areas of Mars are deserts whose soil has turned rusty red, probably through absorption of oxygen from its atmosphere. Mars' diameter is about half that of the Earth. It is extremely doubtful that there are any " Martians" in existence.