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

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

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

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

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

The building blocks of life could have been delivered to Ceres by one or more space rocks from the outer asteroid belt.

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 ...

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

A new study claims it is possible an "alien visitor" could have warped our solar system during its earliest years.

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

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