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

Charon is unusual because it is the largest moon in the solar system compared with its parent body. In fact, Charon and Pluto are so similar in size that they are considered a double dwarf planet ...

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

This mysterious ninth planet could be found within the next ‘two years’, one expert said (Picture: Getty Images/iStockphoto) We’re closer than ever before to knowing whether there is a ninth ...

Timing: Dusk after sunset, but before 9 p.m. local time There are eight planets in our solar system and one dwarf planet (Pluto). Because we live on Earth, the most we could see is a maximum of seven ...

Using the Keck Planet Imager and Characterizer (KPIC), astronomers have performed high-resolution spectroscopic observations ...

The dwarf planet ... reached the inner Solar System only later. For the current study, the researchers looked for previously unknown deposits of organic material on dwarf planet Ceres.

The solar system may hold ... indicate an unseen massive planet. The Kuiper Belt is a distant region of icy bodies. It extends beyond Neptune and includes Pluto and dwarf planets.

Timing: Dusk after sunset, but before 9 p.m. local time There are eight planets in our solar system and one dwarf planet (Pluto). Because we live on Earth, the most we could see is a maximum of ...