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

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun ...

Unless you’re really on the low end of our listener ... proponent of Planet Nine, you know, the person who’s most convinced that there is a new planet in the solar system, is also responsible ...

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 ...

That’s because Pluto was downgraded from a “planet ... our Solar System. The same year that Pluto was ignominiously stripped of its status, a paper was published theorizing that there was ...

She mapped our solar system's "alternate fate" had it housed an extra planet between Mars and Jupiter instead of the existing asteroid belt. They developed a 3D model that simulates how the solar ...

The eight major planets of our Solar ... system can be aligned if you are positioned at the right angle – it's not impossible to imagine someone else on the other end, watching on. "Perhaps ...

Plate tectonics give Earth its mountains, earthquakes, continental drift and maybe even helped give rise to life itself. But do other planets in the solar system have them too?

There are eight official planets (sorry, Pluto) in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. But astronomers have spent the better part of a century ...