Diagram with measured masses and radii for known exoplanets. Blue empty circles are for Venus, Earth, Uranus, and Neptune (from left to right). Purple points are for previously known transiting exoplanets detected from the ground and green points are for planets detected from space by Kepler or CoRoT. Small vertical ticks at the top of the figure help to label each detection. Kepler, CoRoT, and HAT planets have short labels, K, C and H, respectively. GJ 3470 b is over plotted with a red diamond. The gray curves show mass-radius relations for water, rock (MgSiO₃ perovskite) and iron, from top to bottom, respectively (Fortney et al. 2007).