Kepler telescope has pinpointed 50 potentially habitable planets in Milky Way, leading scientists to estimate existence of at least 500m. such worlds in galaxy.

at least 500 million such worlds in the galaxy. The Allen Telescope Array, named for Microsoft Corp co-founder Paul Allen, one of its chief benefactors, consists of 42 dish-like antennas about 20 feet (6 meters) in diameter, operated as one large radio...