The Solar System seems calm, but that tranquility is more fragile than it appears. Now imagine one day looking up and ...

,We all used to think there were nine planets. But in 2006, the solar system was left with only eight planets, when Pluto was no longer classified as such. But is it still possible there is a planet ...

Make room, earthling. We’re moving the other planets in our Solar System into our planetary neck of the woods. Would all the planets fit into this Goldilocks zone? What kinds of gravitational chaos ...

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 ...

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 ...

See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. A leading scientist has told Newsweek about new evidence supporting the ...

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 ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Astronomers have found a distant celestial body — ...