A recent study revealed briny water might exist on the surface of Mars, but this does not necessarily mean life can survive in the planet's harsh conditions.
Researchers at the University of Arkansas analyze data from NASA's Curiosity rover on an impact crater near the planet's equatorial region to make their fascinating findings.
"What we demonstrated is that under specific circumstances, for a few hours per day, you can have the right conditions to form liquid brines on the surface of Mars," said Vincent Chevrier, an assistant professor at the University of Arkansas Center for Space and Planetary Sciences.
The existence of brine could explain mysterious "recurring slope lineae,"which are observed dark streaks on slopes that grow larger during the Red Planet's warm season. Despite the implications of water for the presence of life, the researchers do not believe this means Mars' environment could support organisms.
"If we combine observations with the thermodynamics of brine formation and the current knowledge about terrestrial organisms, is it possible to find a way for organisms to survive in Martian brines? My answer is no," Chevrier said.
Mars' atmosphere freezing and extremely dry, it also has a 200 times lower atmospheric pressure than Earth. Pure water present on the surface would freeze and boil at the same time, causing it to disappear in a matter of minutes. Despite these conditions, NASA's Phoenix lander identified perchlorate salts in polar soil samples in 2008. Perchlorates can absorb atmospheric moisture and can even lower the freezing temperature of water, suggesting briny liquid water could be possible on Mars.
The Curiosity rover has now confirmed the existence of perchlorates in equatorial soil through observations of relative humidity and ground temepratures, and future missions hope to sample these perchlorates directly. While the existence of briny water on Mars is not believed to imply the existence of life, it could help plan future human missions to the planet that would need to tap into local resources. The finding could also help provide insight into the existence of life in Mars' earlier days.
"We need to understand the earliest environment," Chevrier said. "What was happening 4 billion years ago?"
The findings were published in a recent edition of the journal Nature Geoscience.
