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Hairspray Could Help Us Find Advanced Alien Civilizations
Hugh Pickens writes "Charles Q. Choi reports that hairspray could one day serve as the sign that aliens have reshaped distant worlds because one group of gases that might be key to terraforming planets are CFCs. 'Our hypothesis is that evidence of intelligent life might be evident in a planetary atmosphere,' says astrobiologist Mark Claire at the Blue Marble Space Institute of Science. CFCs are entirely artificial, with no known natural process capable of creating them in atmospheres. Detecting signs of these gases on far-off worlds with telescopes might serve as potent evidence that intelligent alien civilizations were the cause, either intentionally as part of terraforming or accidentally via industrial pollution. 'An industrialized civilization will be one that will use its planetary resources for fabrication, the soon-to-be-detectable-from-Earth atmospheric byproducts of which could be a tell-tale sign of their activity,' says astrobiologist Sanjoy Som. CFCs can be easily recognized in planetary atmospheres because their atmospheric 'fingerprint' (i.e. chemical spectra) is very different from natural elements, and are a tell-tale sign that life on the surface has advanced industrial capabilities. Using state-of-the-art computer models of atmospheric chemistry and climate, researchers plan to discover what visible signs CFCs and other artificial byproducts of alien terraforming or industry might have on exoplanet atmospheres. 'We are about a decade away of being able to measure detailed compositions of the atmospheres of extrasolar planets,' says Som."
I think you missed the point about detecting CFCs. It's not about unintended terraforming of someone's home planet. It's about terraforming *another* planet that initially is a bit too cold for the civilisation in question. In human terms we are speaking about creating factories on Mars that pump CFCs into its atmosphere so as to create a more habitable (for us) climate there. See http://en.wikipedia.org/wiki/Terraforming_of_Mars#Using_fluorine_compounds
I'm one of the scientists affiliated with this project. It's very true that SETI in general terms is a "needle in a haystack" sort of search. So one way to look at this is that we are suggesting more "needles" to look for. So far, we are searching for radio waves and optical pulses. Looking for technosignature molecules in a planetary atmosphere (if it actually works, which is what we are trying to figure out with our proposal), is a third needle. I also totally agree with your points about looking for "inadvertent" CFC use by a young and dumb civilization like ourselves. As Hans Adler pointed out, we on the science team are thinking of this more as a search for terraformed worlds. For instance, if we were going to colonize Mars and try and live on the surface in the next century or so, we would likely need to warm up the atmosphere, and CFC's would be a good starting place (and possibly detectable over interstellar space)