The stunning revelation and dramatic photographs were delivered during a crowded press conference at NASA headquarters and simultaneously posted on the Internet. If there truly is subterranean water on Mars that periodically punches through the permanently frozen surface, the finding bolsters expectations that living organisms could currently exist or may once have thrived on the planet, said Ed Weiler, NASA's Associate Administrator for Space Science. Temperatures are so cold and the atmosphere so thin on Mars that exposed water immediately boils off. Malin and staff scientist Ken Edgett formulated a hypothesis to explain how liquid water could survive under such harsh conditions to create the erosion features that look like those on Earth created by flash floods.
Water pressure builds behind the damn until it is great enough to rupture.
The explosive slurry of water, ice and rocks rushes down-slope, carving the gullies and channels seen in the Mars Surveyor photographs. The gullies are found only on the coldest slopes facing away from the sun and many appear in uniform, horizontal layers, their channels pointing downhill like coffee flowing over the brim of a cup. These characteristics are further evidence the curious geological formations were formed by a consistent process, Edgett said. The scientists said the channels weren't carved by lava or landslides because visual and geological evidence is inconsistent with those kinds of events. But the photographic evidence left him with no other plausible explanation.