Meet Kepler-138b, a Mars-sized planet with the smallest measured mass
Thursday, June 18, 2015 - 02:00
in Astronomy & Space
You've heard of hot Jupiters, mini-Neptunes and super-Earths -- but how about an almost-Mars? Scientists using data from NASA's Kepler spacecraft have pinned down the mass of an exoplanet that's slightly lighter than the Red Planet -- making it the smallest such world to have its density measured.