May 20, 2009

Was Early Mars Cold And Wet?

Researchers have long debated the prospect of finding water on Mars, but a new report from researchers in Spain shows that the Red Planet could have been frozen while still maintaining a habitat for liquid water flows at one point in its history.

Some researchers argue that early Mars could not have contained water because its temperatures would have been well below the freezing point for water to exist.

Researcher Alberto Fairen of NASA Ames Research Center and colleagues used computer models to suggest that Mars could have been both wet and frozen.

Fairen showed that fluids that contained dissolved materials could have remained liquid even at temperatures below the freezing point of water at 273 degrees Kelvin.

"Our results are compatible with Mars lander and orbiter data and with climate modeling, and suggest a cold and wet early Mars," Fairen's team wrote.

Their study, "Stability against freezing of aqueous solutions on early Mars" is published in the journal Nature.

Researchers note that many features of the Martian landscape are widely considered to have been formed by the flow of liquid water. But at the same time, data compiled by climate modelers shows that a combination of greenhouse gases at a range of partial pressures makes it hard to simulate the mean global temperatures on the Red Planet above 273 K.

"Solutes could depress the melting point of water in a frozen Martian environment, providing a plausible solution to the early Mars climate paradox," Fairen and colleagues wrote.

"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."

Fairen's team consisted of scientists from NASA's Ames Research Center in California.


Image Caption: The High-Resolution Stereo Camera (HRSC) on board ESA's Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel. Credits: ESA/ DLR/ FU Berlin (G. Neukum)


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