Washington, Sep 28 (IANS): In the first-ever definitive signs of the presence of liquid water -- and possibly life -- on the Red Planet, NASA's Mars Reconnaissance Orbiter (MRO) has captured strong evidence for seasonal flows of liquid salty water on the Martian surface, scientists reported on Monday.

In a paper published in the journal Nature Geoscience, scientists looked at streaks that form on some slopes on Mars during warmer times of the year, having previously suspected they might be caused by flowing, salty water.

According to Alfred S. McEwen, professor of planetary geology at University of Arizona, the team has identified waterlogged molecules - salts of a type known as perchlorates - in readings from orbit.

"That's a direct detection of water in the form of hydration of salts. There pretty much has to have been liquid water recently present to produce the hydrated salt," Dr McEwen noted.

NASA also provided details of this major science during a news briefing at the James Webb Auditorium at NASA headquarters here.

Nearly 4.5 billion years ago, Mars had six and a half times as much water as it does now and a thicker atmosphere.

But most of this water has disappeared into space and the reason is that Mars no longer has global magnetic fields, like on the Earth.

The magnetic field protects the Earth's atmosphere against degradation from energy rich particles from the Sun.