Tuesday, March 16, 2010

Evidence For Life On Mars May Be Staring Us In The Face

Sulphur in silence (Image: NASA/SPL)

From New Scientist:

THE footprint of life on Mars may have been plain to see all along in the sulphurous minerals that litter the planet's surface. What's more, the next Mars lander should be able to detect the evidence.

No mission to Mars has ever found complex carbon-based molecules, from which life as we know it is built. But sulphur is everywhere on Mars - it is more abundant there than on Earth - and it could contain one of the signatures of life. On Earth, the activity of some microbes converts one class of sulphur-containing compounds, the sulphates, into another, the sulphides. The microbes prefer to work with the lighter sulphur-32 isotope, so the sulphides they produce are relatively deficient in the heavier isotope, sulphur-34. Planetary scientists have long wondered whether we could use this pattern to discern signs of life on Mars. Now the prospects for this technique look better than ever.

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