"This is a very exciting discovery because it is our first chance to see an environment on Mars that might allow for the expression of an active biological process, if there is present day life on Mars," said biochemist Lisa Pratt.
Speaking via satellite from Washington, D.C., NASA experts explained their findings to a group of reporters and scientists gathered at Ames Research Center in Mountain View. They pointed out dark flows that appear to emanate from bedrock outcrops.
High definition photos from the Mars reconnaissance orbiter show something flowing on the surface of Mars. It appears to get heavier during the summer and dry up in the winter. It also runs through formations that look like rivers. We've known for awhile Mars has ice at its poles, but this is different.
"What makes these new observations so interesting is that they occur at much lower latitudes where the temperatures are much warmer and where it's actually possible for liquid water to exist," said geophysicist Phil Christensen.
"It did look like water's just oozing out of that bedrock and sliding down the surface there," said NASA planetary scientist Bob Haberle.
NASA scientists who attended the presentation say the finding is promising, but many questions remain.
"The thing that is a little puzzling is that there is an instrument on the same spacecraft that is able to image these locations and measure the presence of water. And it didn't see any signature of water," said Haberle.
One explanation is the Mars orbiter's water detection device is not nearly as sensitive as the high definition camera and these seasonal flows, as they're called, are very narrow. The obvious way to know for sure is to send a Mars rover to take samples, but that will be a challenge.
"These are basically on the sides of craters. So imagine climbing up a canyon wall," said NASA planetary scientist Ted Roush.
But it's a question scientists feel they must answer.
"Having liquid water has a direct connection to the possibility of life," said Haberle.
NASA scientists say it could be years before we know for sure what created those formations on the Martian surface, but if it does turn out to be water, then they say this latest discovery will have created a road map in the search for life on Mars.