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

For decades, we believed our Solar System ended with Neptune, followed only by icy debris and distant dwarf planets. But ...

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. Digital art of distant planet - Dottedhippo/Getty Images On August 24, 2006, our solar system lost a planet. It wasn't by ...

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 ...

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

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 ...

A distant 'exomoon' the size of Jupiter is changing how we think about the cosmos.

Ganymede, Jupiter's largest moon, possesses planet-like dimensions and a hidden ocean. This moon is larger than Mercury and ...

How did the first solids that made up planets, moons and asteroids form from the "hot soup" that characterized our solar ...