Growing up, I was taught that there were nine planets in the solar system. That all changed in 2006, when the International Astronomical Union voted to demote Pluto's status to that of dwarf planet.

Known as Planet Nine or Planet X, it is a hypothetical planet that has long been rumoured to exist in the outer solar system. Although "several claims to have found an extra planet have been made ...

If you buy through a BGR link, we may earn an affiliate commission, helping support our expert product labs. Most of us grew up learning that there are nine planets in our solar system. Back in ...

Narrator: As the solar system grew, four rocky planets: Mercury, Venus, Earth and Mars, were created closest to the Sun. Made of rocks and metals, they have solid surfaces and a central core of ...

A new study presents a compelling new model for the formation of super-Earths and mini-Neptunes -- planets that are 1 to 4 times the size of Earth and among the most common in our galaxy.