The idea that a network of canals criss-crosses the surface of Mars seems quaint today. But a century ago, many people thought it was a foregone conclusion.
That belief originated with the work of Italian astronomer Giovanni Schiaparelli, who was born 175 years ago today.
Schiaparelli was one of the most gifted observers on the planet. Among other things, he found that Mercury and Venus spin very slowly, and that meteor showers are spawned by comets.
When Mars passed unusually close to Earth in 1877, Schiaparelli mapped the planet in great detail. He noted several long, thin lines separating large, lighter-colored features. He called these lines "canali." The word means "channels" -- natural features like riverbeds. But it was translated into English as "canals," implying that they were built by Martians.
The idea caught hold in the popular imagination. Schiaparelli himself didn't support it, but he didn't do anything to squelch it, either. Instead, the idea was taken up by Percival Lowell, who drew maps showing dozens of canals, which stretched hundreds of miles across the surface.
Most other astronomers could see no evidence of the canals through their own telescopes. Even so, maps issued by the U.S. Air Force in the 1950s clearly showed the canals. Not until the first spacecraft flew past Mars in the following decade did they vanish. Mars is indeed a desert, but no canals carry water across its orange surface.
Script by Damond Benningfield, Copyright 2010