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 ...

The solar system may have a ninth planet after all. This one is 5,000 times bigger than outcast Pluto and billions of miles farther away, say scientists who presented "good evidence" for a ...

New evidence shows that, far beyond Pluto, there may exist a hypothetical planet referred to as Planet X or Planet Nine.

The science community may be ecstatic over the discovery of a ninth planet, but the former planet "Pluto" had a totally different reaction. Hours after scientists announced there's solid evidence of ...

(CNN) — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have ...

Pluto may lose its status as a planet, but it remains unique in the solar system. FLAGSTAFF, Ariz. -- It's been 75 years since the discovery of Pluto, but it remains a mystery. Perhaps in another 10 ...