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Using Light's Handedness To Find Alien Life
Rational Egoist writes "Scientists working at the National Institute of Standards and Technology have come up with a novel, easy way to detect life on other planets. Rather than try to measure the composition of atmospheres, they want to look at the chirality of light coming from the planet. From the article: '"If the [planet's] surface had just a collection of random chiral molecules, half would go left, half right," Germer says. "But life's self-assembly means they all would go one way. It's hard to imagine a planet's surface exhibiting handedness without the presence of self assembly, which is an essential component of life."' And they have already built a working model: 'Because chiral molecules reflect light in a way that indicates their handedness, the research team built a device to shine light on plant leaves and bacteria, and then detect the polarized reflections from the organisms' chlorophyll from a short distance away. The device detected chirality from both sources.' The article abstract is available online."
Life on earth exhibits a specific "handedness" or chirality. All DNA twists the same way, for example. Apparently the term for this is homochirality.
http://en.wikipedia.org/wiki/Homochirality
You appear to be wrong on a few big things...
-most compounds are not chiral, so even if a dead planet had some pure enantiomers, they would be insignificant compared to one with life, life produces a crazy large amount of them
-no one has quite figured out why life has the handedness it does, some say it could be because of silicon catalyzing a certain handedness, others disagree, there is not an answer to this question yet, but it makes sense that life would evolve to have a specific handedness so all the parts could be interchangeable and we don't have bizzaro ecoli floating around that can exchange DNA with normal ecoli
-since when does polarized light catalyze chiral reactions?? UV light can catalyze reactions, and chiral molecules can cause a reaction to form with a specific handedness, but only chiral MOLECULES can catalyze reactions to cause a more enantiomericly pure product