Friday, November 4, 2011

Scientists re-thinking theories for life on Mars, 11.04.11

New interpretations of data from NASA and European orbiters are beginning to come together, suggesting that the possibility for life on Mars is not so strong on the surface, but much more promising for the subsurface directly underground.

This interpretation comes after researchers have discovered clay and certain types of minerals in the Martian subsurface. Clay can only be formed through the interaction of liquid water with rock, so finding clay under the surface suggests a much more consistent liquid presence than it does for the surface, which usually only has frozen ice in its craters and at its poles.

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One of the minerals that they have discovered that supports their new theories is a rather icky-colored stone called prehnite. Prehnite can only form in areas where the temperature is over 400 degrees Fahrenheit, so the presence of prehnite and the abundant clay in the subsurface suggests the likelihood for strong hydrothermal (hot water) activity beneath the Martian surface.

That being the case, it is not so strange to think about the likelihood of finding life on Mars. Based on earth’s own geothermal and hydrothermal activity, scientists know it is possible for various kinds of life (usually bacteria and all manner of simple microbes) to live in their own environments, underground, away from the light of the sun.

So, is it time to chuck the rovers and reach for a shovel instead? Not necessarily. More research still needs to be done. There is also more than enough evidence left on the surface of Mars for astronomers to know there was liquid water there at times, and there is still plenty of ice left in some places, so the possibility for life is still there. The idea of finding bacteria on a planet puts the phrase “finding a needle in a haystack” to shame, though. Knowing where to look that is the hard part.

Credit: NASA.

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