As we all learned in elementary school, Alpha Centauri is the closest star system to the Solar System. At a distance of 4.37 light-years (25 trillion miles), it consists of three stars -- the pair Alpha Centauri A and Alpha Centauri B and a small and faint red dwarf, Proxima Centauri, which may or may not be gravitationally bound to the other two stars. Astronomers using ESO telescopes have found clear evidence of a planet orbiting this third star, Proxima Centauri. This long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us. It may also be the closest possible abode for life outside the Solar System.