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 ...

Asteroids are rocky objects that orbit the Sun, just like planets do. There are millions of asteroids of very different shapes and sizes. Some are almost spheres, like planets, but most are ...

Ever since NASA's New Horizons sent back the first-ever photos of Pluto in 2015, the dwarf planet's mysterious heart ... roughly the size of Arizona from north to south. Pluto was discovered ...

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

Earth grew to its final size through one last major collision with another ... Different types of meteorites coming from the asteroids left over in the solar system after planet formation have ...

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.