Mars Surface: Fit for human habitation?

NASA's Hubble Space Telescope snapped this shot of Mars on Aug. 26, 2003, when the Red Planet was 34.7 million miles from Earth.

The picture was taken just 11 hours before Mars made its closest approach to us in 60,000 years.

CREDIT: NASA/ESA

While Mars was likely a more hospitable place in its wetter, warmer past, the Red Planet may still be capable of supporting microbial life today, some scientists say.

Ongoing research in Mars-like places such as Antarctica and Chile's Atacama Desert shows that microbes can eke out a living in extremely cold and dry environments, several researchers stressed at "The Present-Day Habitability of Mars" conference held here at the University of California Los Angeles this month.

And not all parts of the Red Planet's surface may be arid currently — at least not all the time. Evidence is building that liquid water might flow seasonally at some Martian sites, potentially providing a haven for life as we know it.

"We certainly can't rule out the possibility that it's habitable today," said Alfred McEwen of the University of Arizona, principal investigator for the HiRise camera aboard NASA's Mars Reconnaissance Orbiter spacecraft.

Surface water on Mars
McEwen discussed some intriguing observations by HiRise, which suggest that briny water may flow down steep Martian slopes during the local spring and summer.

Sixteen such sites have been identified to date, mostly on the slopes of the huge Valles Marineris canyon complex, McEwen said.

The tracks seem to repeat seasonally as the syrupy fluids descend along weather-worn pathways.

While the brines may originate underground, Caltech's Edwin Kite noted, there is an increasing suspicion that a process known as deliquescence — in which moisture present in the atmosphere is gathered by compounds on the ground, allowing it to become a liquid — may be responsible.

Astrobiologists are keen to learn more about these brines, for not much is known about them at the moment.

"Briny water on Mars may or may not be habitable to microbes, either from Earth or from Mars," McEwen said.

Valles Marineris on Mars