'Earth-like' planet Kepler 78b discovered 400 light-years away
A "lava-world" orbiting 400-light years away has been discovered by scientists, who say the planet they have named Kepler 78b has a similar mass and density to Earth.
Kepler 78b is the smallest exoplanet with a known mass and size. Its orbit and mass was determined by analysing the light emitted from its star that was then blocked by the planet as it passed in front. R