In Search Of Alien Life? Seek Out The Smog

One of the worst byproducts of our industrial society is air pollution. It's a global problem that humans have yet to get under control. One scientist thinks we might not be alone, though. Alien civilizations may be polluting their worlds, and that pollution might be one way to detect them.

Copyright © 2014 NPR. For personal, noncommercial use only. See Terms of Use. For other uses, prior permission required.

AUDIE CORNISH, HOST:

Two words on this next story - polluting aliens. We know air pollution is clogging the skies of planet Earth, but one scientist thinks Earth may be one of many polluted worlds. Alien civilizations, if they're out there, could be messing up their environment, too. And their pollution could be a way to find them. NPR's Geoff Brumfiel reports on the search for extraterrestrial smog.

GEOFF BRUMFIEL, BYLINE: Nobody knows if there's intelligent life out there in the universe. Over the years there've been plenty of ideas about how to spot little, green men.

AVI LOEB: People refer to little, green men. But ETs that are detected by this method should not be labeled as green.

BRUMFIEL: That's Avi Loeb, an astronomer at Harvard University. He's got a new suggestion based on his experience here on Earth. Scan the skies for little, brown men - the chronic polluters. Astronomers have been able to glimpse the atmospheres of planets outside our solar system for a while now. And there's a new space telescope scheduled for launch in 2018 that Loeb says, he could use.

LOEB: 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.

BRUMFIEL: Certain pollutants don't occur naturally. So if astronomers saw them that would point to industrial activity on the planet. And that would indicate intelligence. Loeb has published some calculations in the exciting, September issue of the astrophysical Journal Letters. They showed that if the new telescope looks at the right kind of star...

LOEB: The pollution will be detectable if it's 10 times bigger than in the Earth's atmosphere.

BRUMFIEL: Of course if intelligent life really was intelligent than you might expect they'd pollute less, not more. But, they might have a reason - for example they might be colonizing a cold planet and deliberately creating a greenhouse effect to warm it up. Or high levels of pollution could show that the aliens spoiled their world.

LOEB: It may indicate that we are looking at the ruins of a civilization that destroyed itself. And that would serve as an alarm signal about the risks of not being environmentally friendly.

BRUMFIEL: Either way it would prove that when it comes to making a mess we are not alone in the universe. Geoff Brumfiel, NPR News.

Copyright © 2014 NPR. All rights reserved. No quotes from the materials contained herein may be used in any media without attribution to NPR. This transcript is provided for personal, noncommercial use only, pursuant to our Terms of Use. Any other use requires NPR's prior permission. Visit our permissions page for further information.

NPR transcripts are created on a rush deadline by a contractor for NPR, and accuracy and availability may vary. This text may not be in its final form and may be updated or revised in the future. Please be aware that the authoritative record of NPR's programming is the audio.

Comments

 

Please keep your community civil. All comments must follow the NPR.org Community rules and terms of use, and will be moderated prior to posting. NPR reserves the right to use the comments we receive, in whole or in part, and to use the commenter's name and location, in any medium. See also the Terms of Use, Privacy Policy and Community FAQ.