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

Mercury takes only 88 Earth days to orbit the sun.

The formation of our solar system from a singular nebula raises an intriguing question: why did each planet develop with a ...

While the composition of gas and dust in a molecular cloud is fairly uniform, everything changes once a star begins to form.

For much of January and February, you have the chance to see six planets in our solar system after dark, although two — Uranus and Neptune — will be hard to see without a telescope or high-powered ...

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

Astronomers have discovered a large Earth-like planet orbiting a distant star that could be home to alien life. The exoplanet ...

A new type of exoplanet has been discovered: Enaiposha, also known as GJ 1214 b. Long heralded as a mini-Neptune, new observations have indicated that it is a member of a category never seen before ...

On Feb. 24, from west to east, you can see Mercury, Saturn, Neptune, Venus, Uranus, Jupiter and Mars, all spanning 117.5°, ...