Daves Blog

If aliens wrap their planets in potent greenhouse gases like we do, we'd be able to tell.

That's according to a recent thought experiment in which scientists identified five "artificial" greenhouse gases that, if abundant enough, can be spotted in the atmospheres of certain exoplanets using existing technology, including the James Webb Space Telescope (JWST).

The gases, which include fluorinated versions of methane, ethane, propane, on Earth are known to be some of the most potent and persistent heat-trapping gases emitted by humans during various industrial manufacturing processes, like those used to produce semiconductors, for instance. Because these substances don't naturally form in large quantities — if we're going by Earth chemistry, at least — spotting them in an exoplanet's air would signal the presence of technologically-advanced species, scientists say.