Holden Crater Holdin' Secrets?

Holden Crater is now simply one of thousands of craters that pockmark the surface of Mars. New evidence, however, suggests that Holden has been home-- perhaps more than omce-- to a lake.

Researchers studying the floor of the crater have found debris they say is consistent with debris caused by standing water. They have also found, they believe, a layer of clay, such as what streaming water would lay down as sediment. Currently, scientists think there may have been two periods during which a lake stood in the crater.

The researchers estimate the first lake in Holden may have lasted for thousands of years, while the second lake period may have been only hundreds of years long. Still, they say, if life existed there, the clay layer would be ideal for preserving fossils. NASA's next lander mission is scheduled to launch for Mars next year, and Holden Crater was already on the list of possible landing sites. With this new evidence, it may well jump up that list.