Artist’s impression: five planets orbit the star Tau Ceti, which is just 11.9 light-years from Earth. Astronomers have discovered that the closest Sun-like star, Tau Ceti, is orbited by five planets, one of which is in the “habitable range”. If its existence is confirmed, the planet could be the closest potentially life-harboring world to our own. Tau Ceti, twelve light years away, belongs...