Scientists have discovered the smallest exoplanets yet known, and both represent the closest we have come to finding Earth's twin.
Using NASA's Kepler telescope, researchers at the Harvard-Smithsonian Center for Astrophysics in Cambridge discovered these planets orbiting a sun-like star called Kepler-20 that is 950 light-years from Earth.
The planets are much too hot for liquid water, so the chance of life as we know it on these planets is zero. However, scientists describe this discovery as a significant milestone in the Kepler mission's search for a planet that shares the vital life-sustaining characteristics as Earth. To learn more, look for the paper describing this discovery, which will be published in the journal Nature.