The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

A planetary alignment, or a "planet parade" according to the internet, will grace our night sky just after dusk, according to SkyatNightMagazine. We'll see six planets in the first part of February – ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...

Continent-size islands deep inside Earth's mantle could be more than a billion years old, a new study finds.

Researchers accounted for the previously overlooked structures of the dwarf planet and moon in computer simulations of a ...

Pluto likely acquired large moon Charon in a “kiss and capture” collision billions of years ago. It may have created a subsurface ocean on the icy dwarf planet.