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

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

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

In the depth of winter, a sweeping view of our solar system will glow in the night sky. In total six planets will be visible, ...

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

Beyond Neptune lies the Kuiper Belt, a vast expanse of icy bodies that may hold clues to the solar system’s formation. These ...

Baker said that there are other astronomical events that may be more interesting than the parade of planets. Baker said Mars ...

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

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun ...

A U.S. scientist searching for a civilization across 7 Earth clones circling the red dwarf star TRAPPIST-1 says its own alien ...

When you first learned about the Solar System, you probably saw diagrams that made it look orderly, with planets arranged in ...

Ever since Isaac Newton famously talked about gravity, its dominance as a force in our solar system has been well known. It's ...