A Cold and Wet History on Early Mars?

 

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Even if an early Mars never got above freezing, the brine on its surface could have stayed liquid and supported life, a new study says.

Lead author Alberto G. Fairen, of NASA Ames Research Center in Moffett Field, California, and his colleagues have analyzed the behavior of Martian chemical concentrations found at various mission landing sites, and revealed that warm temperatures wouldn’t have been necessary to support salt-loving life forms.

The authors point out that many features on the Martian surface are believed to have been formed by flowing water and related mineral activity on the surface. Water is a key ingredient for life, but models were having a hard time envisioning a Mars warm enough to support it.

Much evidence has indicated surface temperatures well below freezing.

According to the new study, life may have fared all right anyway.

“Solutes could depress the melting point of water in a frozen Martian environment, providing a plausible solution to the early Mars climate paradox,” the authors write.

Fairen and his colleagues modeled the freezing and evaporation processes of Martian fluids with a composition resulting from the weathering of basalts, as reflected in the chemical compositions at Mars landing sites of Viking 1, Mars Pathfinder, and the rovers Spirit and Opportunity.

“Our results show that a significant fraction of weathering fluids loaded with Si, Fe, S, Mg, Ca, Cl, Na, K and Al remain in the liquid state at temperatures well below 273 K,” or nearly 32 degrees Fahrenheit (zero C), they write.

“This stability against freezing of Martian fluids can explain saline liquid water activity on the surface of Mars at mean global temperatures well below 273 K.”

Photo credit: NASA

Source: Nature