At the center is the sun, a yellow dwarf star that contains 99.8% of the solar system's mass. Everything else — from the eight major planets to dwarf planets, comets, asteroids, and icy objects ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, ...

The presence of another planet in the solar system could explain the odd movements of some of the bodies in the Kuiper Belt.

Researchers say they found a curious dot on infrared images taken 23 years apart that seems to be moving in a manner ...

Pluto, which infamously lost its status as the ninth planet in 2006, is less than four billion miles away from the sun, ...

A new look through decades-old data has unveiled some of the most compelling evidence yet of a hidden ninth planet in the far ...

Discovered in 1930, Pluto was long considered our Solar System's ninth planet, but was unseated in 2006 after the discovery ...

sitting in the Kuiper Belt - a region in our solar system beyond Neptune filled with icy objects, comets, and dwarf planets like Pluto. Since this hidden planet may be so far away, the new study ...