NASA announced on Tuesday afternoon that its Kepler unmanned spacecraft discovered the first two planets nearly identical in size to Earth.
The two planets, named Kepler-20e and Kepler-20f, orbit the same star 1,000 light years away from Earth in the constellation Lyra. Although both planets have radii close to Earth’s, they are thought to have rocky surfaces and are located outside the “habitable zone,” too close to their star to be able to support liquid water, thought to be a necessary condition for life.
