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

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known as a ...

Mars, Venus, Jupiter and Saturn should be visible to the naked eye, but with a telescope you can spot Neptune and Uranus.

Stargazers will be treated to a dazzling six-planet "alignment" this January.

A European-Japanese spacecraft has beamed back some of the best close-up photos yet of Mercury's north pole as part of only the second human survey of our solar system's innermost planet.

Beautiful photos of the six planets aligned in the night sky have emerged online. Mars, Jupiter, Uranus, Neptune, Venus and Saturn are all currently lined up in a row and will be visible in the night ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course.

These embryos, somewhere between small planetesimals and fully formed planets, were abundant during the solar system's formative ... in the earliest days of our cosmic neighborhood.

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known ...

Starting up again Saturday, a sweeping view of our solar system will glow in the night sky. The planetary alignment, or a ...

A European-Japanese spacecraft has beamed back some of the best close-up photos yet of Mercury's north pole as part of only the second human survey of our solar system's innermost planet. The ...