We Probably Aren't Alone

The search for advanced life beyond Earth has periodically been turned upside down

- Sarah Scoles

IN THE LATE 1800s Italian astronomer Giovanni Schiaparelli pointed a telescope at Mars and saw something curious: linear features that he called canali, meaning “channels” or “grooves.” A mistranslation of that word helped lead to a widespread belief that the planet closest to Earth hosted a civilization.

American astronomer Percival Lowell took Schiaparelli’s observations and ran with them. He became obsessed with the Martian markings, which he interpreted as evidence of a sophisticated network of water-transportation channels. “That Mars is inhabited by beings of some sort or other we may consider as certain as it is uncertain what those beings may be,” Lowell wrote in his 1906 book Mars and Its Canals.

It sounds ludicrous now, but it wasn't back then. At the time, ideas about life were evolving rapidly, says David Baron, author of the new book The Martians: The True Story of an Alien Craze That Captured Turn-of-the-Century America. In 1858 Charles Darwin published his theory of natural selection. One year later German scientists Robert Wilhelm Bunsen and Gustav Robert Kirchhoff invented the spectroscope, which they and others used to analyze the chemical signatures in light from the sun and the planets. These studies revealed that other worlds are made of the same elemental constituents as Earth. If life evolves by a natural process, and all planets form in similar ways, why wouldn't life take hold on the Red Planet, too?