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

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

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 ...

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

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

Stargazers will be treated to a rare alignment of seven planets ... Solar System and beyond? In fact, says Millard, "it's just happenstance that they happen to be in this position of their orbits".

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

those that are beyond the eighth planet, with highly “tilted” orbits compared to the ecliptic plane. This seemed odd and illogical as when the Solar system formed, it would be expected that ...

Despite common assumptions, the disk of our Solar System is warped, and the planets travel around the Sun in slightly eccentric (or oblong) orbits. Scientists now think that a mysterious object ...

Credit: MARK GARLICK/SCIENCE PHOTO A super-Earth planet that dips in and out of ... In the context of our solar system, Mars ...