What can we learn from a chunk of rock known as NWA 7034? The rubble was blasted off the surface of Mars eons ago. It made the long, cold journey to Earth. Then it slammed into the Sahara desert as a meteorite.

Even among Mars rocks, this one was special. It had 10 times the water content of other meteorites from Mars, and its texture and color were different. "I'd never seen anything like it," says Carl Agee. He is the lead author of a report about the rock in the journal Science.

The sample has been studied for more than a year in labs across the U.S. and in China. "We know that Mars may have been warm and wet very early in its history," says Agee. "But this sample suggests the water may have lingered much longer than anyone realized."

Scientists say they need more time to study the rock. "There's always more than one way to explain something like this," Agee cautions. "We've got 10 labs working on this meteorite right now," he says. "This was just NWA 7034's debut."

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