Matt_dk writes "The confirmation of the nature of CoRoT-7b as the first rocky planet outside our Solar System marks a significant step forward in the search for Earth-like exoplanets. The detection by CoRoT and follow-up radial velocity measurements with HARPS suggest that this exoplanet has a density similar to that of Mercury, Venus, Mars and Earth, making it only the fifth known terrestrial planet in the Universe. The search for a habitable exoplanet is one of the holy grails in astronomy. One of the first steps towards this goal is the detection of terrestrial planets around solar-type stars. Dedicated programs, using telescopes in space and on ground, have yielded evidence for hundreds of planets outside of our Solar System. The majority of these are giant, gaseous planets, but in recent years small, almost Earth-mass planets have been detected, demonstrating that the discovery of Earth analogues — exoplanets with one Earth mass or one Earth radius orbiting a solar-type star at a distance of about 1 astronomical unit — is within reach."