Washington Post: The nearest exoplanet yet discovered is Earth-sized and orbits Alpha Centauri B. From the European Southern Observatory in Chile, astronomers detected the planet indirectly by measuring the wobble of its star. According to Xavier Dumusque of the University of Geneva, lead author of a recent paper published in Nature on the subject, the rocky planet’s surface is probably lava-like because of its proximity to its sun—much closer than Mercury is to our Sun. Although astronomers have so far discovered 842 planets orbiting other stars, they have yet to find one similar to Earth—a rocky planet orbiting a Sun-like star at the right distance for water to be in a liquid state.