Alien astronomers could discern Earth's features 14:58 21 December 2007 NewScientist.com news service Stephen Battersby Aliens spying on us from another star system might be able to discern continents and oceans on our planet, using technology barely more advanced than our own. In imaginary form, these inquisitive extraterrestrials have been helping astronomers work out how much detail the next generation of space telescopes could reveal on Earth-like planets orbiting other stars. Seeing any detail at all is a tough task. Even at the distance of the nearest stars, only a few light years away, terrestrial planets would appear so small...