Planetary Landscapes Could Alien Life Forms Survive Without Water Beyond the Cell?“Follow the water” has long been the mantra of our NASAs search for alien life in the Solar System and beyond. We continue seeking conditions where water can remain liquid either on a world’s surface or elsewhere within a planetary body. This approach makes a lot of sense. Life as we know it requires water for the complex chemistry that enables growth and reproduction. Where there is water, we believe life has a chance.“Basically, all active cellular systems live in watery environments,” said John Hallsworth, an environmental microbiologist at Queen’s University Belfast. “Without an aqueous milieu both inside the cell and outside, microbes can die, or, at best, manage to survive in an inactive state.” A good question to ask, then, is how much water at a minimum does life need? As a recent study in the journal Environmental Microbiology by Hallsworth and colleagues explains, the answer is not simply one of water quantity, but rather of its concentration.Water, as we all know from brewing tea or making Kool-Aid from a powder mix, is excellent at incorporating other molecules into its liquid medium. More relevantly to life, water is a potent solvent that easily dissolves salts from the oceans and minerals on land. As a result, water can become disagreeable or even toxic to life, based on what dissolves in it. Life therefore needs “biologically available” water, extractable from its surroundings.“Although it may sound counterintuitive, the quantity of water present in a potential habitat is not a meaningful measure of how biologically available water molecules are,” said Hallsworth. “It is, however, the concentration of water molecules that acts as a determinant for life processes.”...Read more at: dailygalaxy/my_weblog/2014/11/nasa-could-alien-life-forms-survive-without-water-beyond-the-cell.html Image Credit: Dale Andersen, the SETI Institute Carl Sagan Center.
Posted on: Wed, 05 Nov 2014 12:07:01 +0000
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