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Asymmetric Molecule, Key To Life, Detected In Space For First Time (yahoo.com)
schwit1 quotes a report from Yahoo News: Scientists for the first time have found a complex organic molecule in space that bears the same asymmetric structure as molecules that are key to life on Earth. The researchers said on Tuesday they detected the complex organic molecule called propylene oxide in a giant cloud of gas and dust near the center of the Milky Way galaxy. Akin to a pair of human hands, certain organic molecules including propylene oxide possess mirror-like versions of themselves, a chemical property called chirality. Scientists have long pondered why living things make use of only one version of certain molecules, such as the 'right-handed' form of the sugar ribose, which is the backbone of DNA. The discovery of propylene oxide in space boosts theories that chirality has cosmic origins. The scientists in the new study used radio telescopes to ferret out the chemical details of molecules in the distant, star-forming cloud of gas and dust. As molecules move around in the vacuum of space they emit telltale vibrations that appear as distinctive radio waves. Future studies of how polarized light interacts with the molecules may reveal if one version of propylene oxide dominates in space, the researchers said.
When I first read this, I thought they had found a non-50:50 ratio of enantiomers, but it appears that they have simply detected the presence of propylene oxide in some form, which doesn't seem terribly surprising to me. It would be fascinating if they did discover that one enantiomer was favoured but I'm not sure how this could be done short of collecting the chemical... are there any convenient sources of polarised light in space?
What would be interesting is if there was found a chiral molecule in space that was significantly biased to one enantiomer. Depending on the context of what was found this would be proof of either extraterrestrial life, or a cosmic enantiomeric enrichment process that would have huge implications for understanding the origin of life.
It would most certainly not be proof of either extraterrestrial life. It would only prove that there is some process going on in space producing a biased enantiomer. Could life be the process doing it? Yes, but unless we are claiming to know everything that occurs at the center of the galaxy where these enantiomers have been found, it would not be scientifically valid to claim it as proof of life.
As for an enantiomeric enrichment process and the implication for understanding the origin of life, that too is pretty far fetched. It could help explain why there is a bias such as the immense gravitational fields, or heat or radiation or any number of things known and unknown. But, whatever that cause is, it would need to be determined if the bias had been the other way, would it had prohibited the formation of life? In otherwords, do all of our enantiomer exist in their current direction because the other direction would not be conducive to life (as we know it) or do they exist in their current direction because they are just made up of what happened to be the dominant version?
If the answer of that question is the former, then there may be huge implications for understanding the origin of life. But only if we could determine what caused the bias in the beginning and whether or not that force still exists or the bias seen now is just an artifact (replicating molecules tend to replicate in the same pattern).