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

Surprised astronomers said Thursday they have discovered a star with planets in a bizarre order that defies scientific expectations -- and suggests these faraway worlds formed in a manner never seen ...

Something strange is happening on the outskirts of our Solar System. It could be a large, mysterious planet. Or, it could be ...

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

The curious minds at What If discover what happens if a new planet appears in our solar system, revealing gravitational ...