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

This may explain the strange properties of the orbits of our solar system's planets, which are not quite perfectly circular, and all lie on slightly different planes. NASA artist’s conception of ...

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

Beyond Neptune lies the Kuiper Belt, a vast expanse of icy bodies that may hold clues to the solar system’s formation. These ...

Though the planets are always “aligned,” seeing more than four in the sky is more uncommon. February’s lineup is a chance to ...

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

A new study claims it is possible an "alien visitor" could have warped our solar system during its earliest years.

Here’s what you should know when you go outside to see for yourself: Yes, the planets are indeed lined up across our sky. No, ...

Spotting one or two of the planets in our solar system is well worth a good skywatch, but seeing (almost) all of them in a ...

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

The new exoplanet, Enaiposha, also known as GJ 1214 b has never been seen before and is now officially being called a "Super-Venus." ...

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