The simulation of the Solar System that came the closest to the observation was the presence of a small planet, between the ...

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth ...

Astronomers are investigating a potential hidden planet, dubbed Planet Y, far beyond Neptune. Its gravitational pull is ...

The methane gas may constitute a rarefied atmosphere, or it may come from erupting plumes on Makemake’s surface.

Pluto's unusual eccentricity and tilt is likely due to its interactions with neighboring Neptune and other giant planets, ...

Two bright green comets are streaming through the skies and are visible to skygazers in the Northern Hemisphere ...

Pluto, the king of the underworld, was the ancient Romans' embodiment of death itself. Known as Hades in Greek mythology, ...

Astronomers using the Hubble Space Telescope have uncovered the remains of a frozen, Pluto-like world being devoured by a distant white dwarf star.

Comet Lemmon will have its closest brush with Earth on or around Tuesday, Oct. 21. Comet SWAN should have its flyby with ...