Recent photographs seem to suggest that water could have been present on the surface of Mars as little as five years ago.

The discovery resulted from images taken by the Mars Global Surveyor which first recorded gullies and trenches that could have been made by fast-flowing water coursing down cliffs and crater walls.

Scientists in the USA decided to retake images of the gullies to search for any sign of recent activity.

Two of those originally photographed in 1999 and 2001 then photographed again in 2004 and 2005 showed changes consistent with water having flowed down the side of the crater. The discovery was made by scientists at the San Diego-based Malin Space Systems which operated a camera aboard the spacecraft.

Link (via BoingBoing)