NASA Confirms There's Water Flowing On Mars

NASA and JPL made a major announcement today: they've found the "strongest evidence yet" of salty water flowing intermittently on present-day Mars.

By using an imaging spectrometer, scientists found that on NASA's Mars Reconnaissance Orbiter (MRO)—a spacecraft that has been studying Mars from orbit for the past nine years—the mysterious dark streaks they saw on slopes on the planet's surface appear to be hydrated minerals flowing on the Red Planet.

"The water flows could point NASA and other space agencies towards the most promising sites to find life on Mars, and to landing spots for future human missions where water can be collected from a natural supply," according to the Guardian.

The findings were published today in the Nature Geoscience journal, and three of the co-authors spoke at a press conference today explaining their discovery.

"Mars is not the dry, arid planet that we thought of when we passed," Jim Green, NASA Planetary Science Director, said in the press conference. "Today we're going to announce that under certain circumstances, liquid water has been found on Mars."

What's even more interesting is that the briny water seems to ebb and flow with the seasons. "These are dark streaks that form in late spring, grow through the summer and disappear in the fall," according to NASA. The streaks appeared in various areas on Mars, in locations where the temperatures were minus 10 degrees Fahrenheit, but would vanish in much colder areas.

"Our quest on Mars has been to 'follow the water,' in our search for life in the universe, and now we have convincing science that validates what we've long suspected," John Grunsfeld, astronaut and associate administrator of NASA's Science Mission Directorate said in a release. "This is a significant development, as it appears to confirm that water—albeit briny —is flowing today on the surface of Mars."

The Nature Geoscience paper explained that the hydrated salts called perchlorates formed the downhill dark streaks, called recurring slope lineae (RSL). "This means the water on Mars is briny, rather than pure. It makes sense, because salts lower the freezing point of water."

However, not so fast, folks looking for extraterrestrial life on the cold, desert planet: the water found in the perchlorates may not be enough to support terrestrial life, though the authors said, "the detection described here warrants further astrobiological characterization and exploration of these unique regions on Mars," Mashable reports.

"Experience in the driest places on Earth tells us that life is very creative at taking advantage of very small amounts of water to survive and even thrive," Alfonso Davila, a SETI researcher unaffiliated with the new study, told Mashable.

Scientists still don't know where the water comes from, but it could be coming from Mars' underground ice or salty aquifers, or condensation from the planet's thin atmosphere.

USA Today reports that scientists first noticed the dark streaks five years ago, which launched their study to discover today's findings. Scientists have theorized that more than 4 billion years ago, the Red Planet had enough water to fill lakes and rivers, though today's findings show the most direct evidence of the water.

Here's an animated video simulating flying over one of the areas on Mars with dark streaks coming down the slopes during the warmer seasons. The streaks about the length of a football field: