Gliese 581d, an exoplanet (planet outside our solar system) seven times the size of Earth, orbits a star called Gliese 581 that is 20 light-years away in the constellation Libra.

When Gliese 710 enters our solar system, it could trigger 170 asteroid impacts a day—ten times the current rate.

The search for extraterrestrial life is one of the most exciting frontiers of modern science. Thanks to recent discoveries of exoplanets like Gliese 581 g, Kepler-22 b, Kepler-186 f, and Kepler ...