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New Clues from Mars

Does water flow on Mars? New photos released last Wednesday offer powerful evidence that it does. The images were taken by NASA's Mars Global Surveyor. Though they don't actually show water, they show changes in craters that took place over the last seven years. Scientists believe that the recent changes are likely a result of water flowing through the craters.

The photos excited scientists looking for signs of past or present life on Mars. Liquid water is necessary for sustaining life. Scientists believe there was water on Mars long ago, and evidence of ice has been spotted on Mars's north pole. But this is the best evidence yet of liquid water on the Red Planet.

"This is a squirting gun for water on Mars," says scientist Kenneth Edgett, who works with the Global Surveyor.

Other scientists say that the photos are not good-enough proof. "Nothing in the images proves that the flows were wet," says Allan Treiman, a geologist.

Earlier last week, NASA unveiled plans to build a permanent international base camp on the Moon. By 2024, space officials hope to have a permanent crew of astronauts on the base.

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