Add Yahoo as a preferred source to see more of our stories on Google. Digital art of distant planet - Dottedhippo/Getty Images On August 24, 2006, our solar system lost a planet. It wasn't by ...

Add Yahoo as a preferred source to see more of our stories on Google. An illustration showing Planet Nine, a hypothetical, undiscovered planet in our solar system. New research now suggests the ...

If you're an early riser, you're in for a treat. On Sunday, Aug. 10, six planets — Mercury, Venus, Jupiter, Saturn, Uranus and Neptune — will line up in what is called a "planetary alignment." This ...

Starting Jan. 21, Canadians can see a rare celestial event as six planets line up in the evening sky, mostly visible to the ...

(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 ...

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 ...