The approximately 65,000 images the Surveyor orbiter has beamed home in the nearly three years it has been circling Mars are full of this kind of expected hydro-scarring. But some of the pictures took scientists by surprise. The older a formation is, the more likely it is to have been distorted over the eons--smoothed by periodic windstorms or gouged by the occasional incoming meteor. However, a few of the newly discovered water channels look flesh. That discovery has lead astonished researchers to conclude that these channels may have been recently formed. Paleontologists have long assumed that if underground water was going to bubble up on Mars, it would have to be somewhere in the balmy equatorial zones, where temperatures at noon in midsummer may reach 68 degrees Fahrenheit (20 degrees Centigrade). Almost all the new channels, however, were discovered at the planet's relative extremes--north of 30 degrees north latitude and south of 30 degrees south latitude--and all were carved on the cold, shaded sides of slopes.

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