The International Astronomical Union defines a planet as a celestial body that orbits the sun, is massive enough that gravity has forced it into a spherical shape, and has cleared away other objects ...

Astronomers have uncovered a distant planetary system that flips a long-standing rule of planet formation on its head. Around the small red dwarf star LHS 1903, scientists expected to find rocky ...

Our galaxy's most abundant type of planet could be rich in liquid water due to formative interactions between magma oceans and primitive atmospheres during their early years, according to new research ...