It's only been a few weeks since scientists confirmed there is indeed water on Mars. But they have yet to determine if life exists in the briny water or if that moisture is coming from the atmosphere or from underground.
Nadine Barlow is a professor of physics and astronomy at Northern Arizona University, and she's trying to answer those questions. "If these dark streaks are forming because water is seeping out of the near surface region," says Barlow, "we probably have liquid water underground. And we know that life forms love to have liquid water, so there are certainly areas that we're going to focus on in terms of future exploration trying to understand whether or not Mars may have ever had life or if it might still have life today."
Barlow is studying images taken by a highly sensitive camera called a spectrometer. It's attached to an orbiting spacecraft collecting data from Mars. The "dark streaks" she refers to are liquid streams full of magnesium salts. Many are as big as a few 100' long and about 5' wide. They tend to occur around the Martian equator in canyons, on the slopes of craters, and on flat surfaces.
"In this image," Barlow points out, "you can actually see there are dark streaks that exist in this one image from May of 2007. And then when this same area was imaged back in September 2012, there's a brand new streak that actually formed there. And so that's the characteristic of these recurrent slope lineae...one time you see them, and the next time you don't, and vice versa."
Barlow is part of COSPAR, an international organization that sets guidelines for protecting planetary surfaces so that Earthlings don't contaminate them. She says the areas of Mars with flowing water - or recurrent slope lineae - are considered "special regions". Currently, they're off limits for space exploration until we can be sure that visiting spacecraft are not carrying bacteria that can start growing there.