NASA announces water on Mars

Space

Mars from the Viking Orbiter, 1980.
Image: NASA/USGS.

Warm season flows on slope in Newton Crater
Image: NASA/JPL-Caltech/Univ. of Arizona.

On Monday, NASA announced that signs of liquid water have been found on Mars. The Mars Reconnaissance Orbiter spacecraft found evidence of the liquid on the Martian surface, in long dark spots on the Red Planet thought to be formed because of water flow.

In a news conference, NASA's planetary science director, Jim Green said, "We now know Mars was once a planet very much like Earth with warm salty seas and fresh water lakes [...] but something has happened to Mars, it lost its water."

Water is thought to flow down slopes in the warm summer months and dry up as the temperature drops seasonally. Scientists have different theories about the water's origin, as perhaps from the Martian atmosphere or from ice below the surface.

In 2011, Lujendra Ojha proposed the theory of water on the Martian surface, after studying salt samples from Martian soil. The temperature of Mars is close to the freezing point of water, but the presence of salt lowers the freezing point. Alfred McEwen, professor of planetary geology at the University of Arizona, described the water as "briny". Moreover, the recurring slope lineae (RSL) on the surface of Mars are found to slide down the slope in the hotter season indicating the presence of water.

NASA's associate administrator John Grunsfeld said those observations gave a better picture about the planet's resources that could be helpful in the future. Grunsfeld tweeted Water on Mars, not just frozen. Is anything drinking it? Someday we wil find out on our #JourneyToMars.

To mark this discovery