Water is crucial to life as we know it, so it’s one of the key things astronomers look out for on exoplanets. And now, water vapor has been detected in the atmosphere of a potentially habitable exoplanet for the first time.
Water vapor has turned up on planets outside our solar system before, but none of those were anything close to liveable. These worlds include broiling hot versions of our own Jupiter, Saturn and Neptune, and steamy Super-Earths that are more water than rock.
But this new discovery of atmospheric water vapor is more promising. The planet in question is known as K2-18b, and orbits a red dwarf star some 110 light-years away in the constellation of Leo. It’s rocky and Earth-like, measuring 2.25 times wider and eight times more massive than our home planet.