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

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

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

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

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course.

It is not often that all the planets in the Solar System other than ours are lined up across the night sky for us to see.

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 ...

The seven planets will not be perfectly aligned, but will appear in an arc across the sky due to their orbital plane in the Solar System.

These features are not seen in any previously identified exoplanet ... and its extreme lack of hydrogen expands our understanding of the diversity of planets (just like this strange object in our ...

The rare astronomical event will see Mars, Jupiter, Uranus, Venus, Neptune, Mercury and Saturn appear at the same time, ...

The only planet not visible is Mercury ... This imaginary path is called ecliptic, the plane of the solar system. Stay connected with the most up-to-date coverage of the stories that matter.

In August 2006, the International Astronomical Union made the controversial, but correct, decision to demote Pluto from its ...