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

But of these planets, which is nearest to the sun? Mercury is the closest planet to the sun, followed by Venus, Earth, Mars, ...

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 ...

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

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

Six of our cosmic neighbors are expected to line up across the night sky tonight, in what has been dubbed a "planetary parade ...

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 ...

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

Six planets are parading across the sky, appearing as some of the night's brightest stars. A few easy tips can help you ...

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 ...