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 ...

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 – ...

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

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

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

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

A planet-size object that possibly once visited the solar system may have permanently changed our cosmic neighborhood by warping the orbits of the four outer planets, a new study suggests. The ...