Mars: The Red Wanderer

Abstract

At the close of the 19th century, Mars was imagined to be the most likely abode of extraterrestrial life. The available science hinted that conditions on its surface were similar to those on Earth. Observations of unusual linear surface features by some of the leading astronomers of the day ultimately led a few of them to promote the idea that life, and even intelligent beings, lived there. Even among scientists, the belief that Mars should have some form of life proved hard to shake; as late as the 1950s some astronomers felt that color changes detected on the martian surface were best explained by the seasonal growth of vegetation. While early scientific speculation about a martian civilization was quickly discredited, the notion settled into popular culture and inspired writers from Ray Bradbury to H. G. Wells. These stories stoked public imagination about the possibilities of contact with extraterrestrial civilizations. By the mid-1970s microscopic life was the most advanced organism anyone seriously expected to find on Mars. Biological experiments sent to the surface detected something, but probably not life. As we’ll see, the scientific story doesn’t end there.