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

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

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

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

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

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 – ...

Simpson and Chen ran mathematical models looking at how differently sized Earth-like worlds would have affected the rest of ...

Astronomers have discovered extremely powerful winds pummeling the equator of WASP-127b, a giant exoplanet. Reaching speeds ...

When astronomers found a large world farther out than Pluto, it became one of the final nails in the coffin of our ninth ...

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

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