Planet Nine is a hypothesized massive planet, first proposed in 2014, that is speculated to orbit far out in the solar system. It has not been detected formally. Instead, astronomers have inferred its ...

A small team of planetary scientists from the California Institute of Technology, Université Côte d'Azur and Southwest Research Institute reports possible new evidence of Planet 9. They have published ...

Sixty-six light-years away, an Earth-sized exoplanet completes an orbit in under six hours, skimming around its star at nearly one-hundredth the distance that Mercury orbits the Sun. This planet is on ...

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 ...

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...

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 ...