Their observations of a faint, cool M-dwarf star called LHS 1903 revealed a system with a rocky world at its outer edge. LHS ...

A planetary system 116 light-years from Earth has a peculiar pattern. It could flip the script on how planets form, scientists say.

By Will Dunham WASHINGTON, Feb 14 (Reuters) - Astronomers have observed a planetary system that challenges current planet ...

Astronomers have discovered the earliest seeds of rocky planets forming in the gas around a baby sun-like star, providing a precious peek into the dawn of our own solar system. It’s an unprecedented ...

Astronomers believe they have uncovered evidence of a previously unknown ninth planet lurking in the not-too-distant reaches of the solar system. This hypothetical world, dubbed "Planet Y," could be ...

Exoplanets are planets outside Earth's solar system. In 1995, a gas giant named 51 Pegasi b, which orbits a star similar to Earth's sun, etched its name in history as the first exoplanet ever ...

Astronomers have found a distant world that challenges planetary formation theory, with a rocky planet where gas giants should be.

It is a question that feels like it should have a straightforward answer: how many planets are there in our solar system? Since Pluto was relegated back down to dwarf planet status, almost everyone ...

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth than the hypothetical Planet X, which astronomers have been hunting for ...