The subject of extraterrestrial life tends to bring out both our inner utopianists and dystopianists. In fiction, aliens are usually depicted as either extremely cute and benevolent (E.T.-style) or ruthless planet pillagers (Kaiju-style).
Still, both extremes have one thing in common: The alien characters show basic competence when it comes to ensuring the survival of their race. They may lose their kids on other planets as with E.T., and they may underestimate that priceless Smith/Goldblum chemistry, but they aren’t as fundamentally self-destructive as our own species.
But as it turns out, aliens saddled with comparable foibles to humanity might be the easiest for us to find. At least, that’s what researchers based out of the Harvard-Smithsonian Center for Astrophysics speculate in a study announced today. The team suggests for signs of specific industrial pollutants in the atmospheres of exoplanets could help streamline the search for alien life.
"We consider industrial pollution as a sign of intelligent life, but perhaps civilizations more advanced than us, with their own SETI programs, will consider pollution as a sign of unintelligent life since it's not smart to contaminate your own air," said lead author Henry Lin in Harvard’s statement.
Admittedly, this concept of screening exoplanets for signs of industrial waste is not entirely new. Astronomers have searched for telltale megastructures like Dyson spheres in the spectrums of distant stars, while others have suggested looking for artificial debris used for mining.
For the rest of the story: http://motherboard.vice.com/read/to-find-aliens-we-should-look-for-industrial-polluted-wastelands