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

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

If everything in our solar system formed from the same solar nebula, why do the planets have different compositions? Herbert WichTitusville, Florida To better understand why the planets have variable ...

Two exciting new studies detail the life-supporting contents of a 4.3-ounce sample of the asteroid Bennu. The OSIRIS-REx ...

Worlds will align for a "planetary parade" in January, with four bright and easily visible to the naked eye. But an even ...

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 ...

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 ...

Because planets always appear in a line, the alignment isn't anything out of the norm. What's less common is seeing so many ...

Sky watchers are in for a treat this month as the stars align to give amateurs a shot to see six planets at once.

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

This provides another piece of the puzzle to understand how planets and ... New studies offer a clearer picture of how the outer solar system formed and evolved based on analyses of trans ...