In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

Relative sizes of the newly discovered habitable-zone planets and Earth. Left to right: Kepler-69c, Kepler-62e, Kepler-62f and Earth (except for Earth, these are artists' renditions). Image credit: ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it. Some astronomers ...

The new plot twist is that in order to keep enough nitrogen and phosphorus near its surface, a planet has to start out with ...

An international team of astronomers, co-led by researchers at the University of Galway, has made the unexpected discovery of a new planet. Detected at an early stage of formation around a young ...