Today at the annual meeting of the American Astronomical Society, NASA's Kepler team announced the discovery of the smallest exoplanet yet identified. The planet, called Kepler-10b, is only 1.4 times the diameter of the Earth, but it's significantly more heavy and quite a bit hotter, since it orbits well inside the radius of Mercury. Its detection, however, provides a clear indication that Kepler will be able to pick up similarly sized bodies orbiting further out from their host stars.