Scientists for years have been analyzing exoplanets (or planets orbiting stars beyond our solar system) in an attempt to locate traces of water vapor in their atmospheres in order to gauge their potential for supporting life--ours or that of extraterrestrials. But now researchers are saying that actual pollution traces might hold the key to determining if alien civilizations reside on observable exoplanets. 

According to ABC News, scientists at the Harvard-Smithsonian Center for Astrophysics postulate that sometime within the next decade it could be possible to "detect the presence of an industrialised alien society," living on another world. Specifically, scientists say they will eventually be able to sense if any chlorofluorocarbons (CFCs) are being produced on exoplanets.

Typically, CFCs are chemicals produced as a byproduct of major industrial processes that have a measurable (negative) effect on a planet's atmosphere, which is what astronomers would eventually be looking for. 

A new NASA telescope scheduled to launch in 2018 might help to make this new form of alien life detection possible. The James Webb Space Telescope, estimated to cost $8.7 billion, will be reportedly "between 10 and 100 times more powerful" than the Hubble Space Telescope, reports ABC. 

Yet scientists are also trying to curb expectations of finding signs of alien pollution anytime soon. And that's because there are still strict limits within such detection would have to occur. Only certain types of pollution under very specific conditions could hoped to be found by our telescopes. 

Apparently the CFC levels on an exoplanet would need to be "10 times those on Earth" in order for the new James Webb Space Telescope to detect them.

Another limitation is that that JWST can only look for CFCs in "Earth-like" exoplanets, and only those orbiting white dwarf stars. White dwarfs are stars that have "died and lost all their hydrogen fuel," says ABC. 

In order to find pollution on an exoplanet like our that is orbiting a much brighter sun, like ours, a much more powerful observing instrument is necessary, and unfortunately such technology has yet to be invented. 

Harvard-Smithsonian scientists have also painted a more bleak scenario that the discovery of alien pollution could point to. It is estimated that some pollutants can remain in our own atmosphere for 50,000 years, and if that's the case then scientists, if they do find alien pollution on an exoplanet, could very well be peering into a dead world in which its civilization "annihilated itself."

Avi Loeb, co-author of the Harvard-Smithsonian study stated of this possibility: "it would serve as a warning sign of the dangers of not being good stewards of our own planet."