Pictures taken by the camera on NASA's Mars Global Surveyor suggest that rivulets of liquid water were flowing on the Red Planet within the past few years and may still be flowing today, welling up from beneath the Martian surface and streaming down gullies along the sloping walls of impact craters.
Two craters in particular caught the attention of NASA scientists. Both are in the planet's southern hemisphere, and both looked unremarkable at first glance. That changed when the Surveyor team reimaged the craters over several years and spotted two brightly streaked gullies with branched endings—a hallmark of flowing water—that were not visible in earlier pictures. The researchers speculate that the streaks formed when water bubbled up from a subsurface reservoir and ran down the gullies, leaving behind a pale-toned trail of sedimentation that is seen in the Surveyor snapshots as a bright line against a darker background.
"We reimaged ...
