Let's hope that alien environmentalists have been as outnumbered by polluters as their counterparts have been here on Earth. Someday pollution could very well be the key to discovering life on other planets.
In a paper to be published in Astrobiology, astronomers lead by Jean Schneider of the Paris Observatory in Meudon, France suggest that light and chemical pollution could point the way to alien civilizations. Given the right mix of telescopes and sensors scanning alien planets, it could someday be possible to detect substances like CFCs that aren't naturally formed.
Light pollution could be another thing to look for. Artificial light could show up on readings of planets as noticeable variations from what's expected.
Current technology isn't quite up to snuff rigth now; we have a few cycles of technological advancement to get through before we can actually start looking for alien pollution, but it's a really interesting idea to start tacking towards.
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