There are a couple of ways that scientists can date planets, so which planets formed first in our solar system?

Astronomers have discovered fresh evidence suggesting the possible existence of an unseen planet in the far reaches of our solar system.

Normal gases, like the air you breathe on Earth, are made up of atoms bouncing around. Atoms consist of a positively charged bundle of particles called the nucleus and negatively charged particles ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...