Air pollution is clogging the skies of our planet. Now one scientist thinks Earth may be just one of many polluted worlds — and that searching for extraterrestrial smog may actually be a good way to search for alien intelligence.
“People refer to ‘little green men,’ but ETs that are detected by this method should not be labeled as green,” says Avi Loeb, an astronomer at Harvard University.
The idea of finding alien polluters may be a bit of a long shot, but Loeb says it’s possible.
Astronomers have been able to glimpse the atmospheres of planets outside our solar system for a while now. In 2018, NASA will launch the James Webb Space Telescope, which will be larger and better than ever at looking at extrasolar atmospheres.
“The idea would be that when a planet like the Earth is passing in front of its host star, a small fraction of the light from the star would pass through the atmosphere and show potentially evidence for these pollutants,” he says. . . .