Targeting alien polluters
Humanity is on the threshold of being able to detect signs of alien life on other worlds. By studying exoplanet atmospheres, we can look for gases such as oxygen and methane that only coexist if replenished by life. But those gases come from simple life forms such as microbes. What about advanced civilizations? Would they leave any detectable signs? They might, if they spew industrial pollution into the atmosphere. New research by theorists at the Harvard-Smithsonian Center for Astrophysics (CfA) shows that we could spot the fingerprints of certain pollutants under ideal conditions. This would offer a new approach in the search for extraterrestrial intelligence (SETI). “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 Harvard student and lead author...