When looking for aliens, try finding their pollution

Fluorinated gases in exoplanet atmospheres might be detectable by future telescopes

SMOG ALERT  A brown haze envelops a rocky planet orbiting a white dwarf star, in an artist’s illustration. Future telescopes might be able to detect such pollution from afar.

Christine Pulliam/CfA

In the search for “little green men,” astronomers may want to focus on extraterrestrials that aren’t too green.