First real evidence for a rocky exoplanet

Wired.com: When astronomers discovered COROT-7b in February, they couldn’t determine its mass because they didn’t have precise enough measurements of the velocity of its star. Now, using 70 hours of observation data from the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph, scientists from the European Southern Observatory have calculated that the exoplanet is only about five times more massive than Earth.

Combined with the planet’s known radius, which is almost twice that of Earth, the new mass measurement makes COROT-7b the first exoplanet with a known density similar to Earth’s.