We have detected only one transiting planet that has a mass below 10 Earth masses. This world, CoRoT-7b (named after the European Convection, Rotation and planetary Transits satellite) has a radius 1.7 times that of Earth. The planet is just around 4.8 times Earth’s mass. This gives it a density about the same as Earth’s, implying that it is likely rocky in composition. This makes CoRoT-7b the only confirmed rocky extrasolar planet, and therefore the largest exoplanet of this composition.