Our Solar System has eight planets, a few dwarf planets and more than 200 moons. But wait. Are you seeing double? Or did ...

As far-fetched as it may seem, quirks of orbital mechanics could allow hundreds of planets to be packed around a star ...

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

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't been for lack of trying. According to a new paper by Thomas Winterhalder of ...

Add Yahoo as a preferred source to see more of our stories on Google. About 4.6 billion years ago, a celestial cloud collapsed, paving the way for our solar system to form. Then, a nebula with strong ...

The Sun’s death is not an event the planets will quietly survive—it is the trigger for their orbital undoing.” ...

Learn how Pluto nearly kept its planet status in a proposed 12-planet Solar System as its demotion marks its 20th anniversary. Eight days before Pluto lost its planetary status, it appeared ready to ...

The fate of our solar system is written in the stars—well, one star to be precise: the sun. Estimates of what the end will ...