Resumen de Exiled to the solar system's edge
Astronomers announced on 20 January that they have strong evidence for a planet around 10 times Earth's mass lurking unseen in the outer solar system. If it bears out, this world would fill a hole in the solar system's family tree: a missing super-Earth. Super-Earths, also known as mini-Neptunes since they may be gassy or rocky, are among the most common planets in the Milky Way.
