A fresh study of the Kuiper Belt’s structure has revived that far-out question, pointing to a possible Earth-sized ...

Scientists have recently unveiled a remarkable discovery in the outer reaches of our solar system: a space fossil located 4 ...

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 ...

Scientists think there may be a ninth planet hiding in the distant reaches of the solar system — and a new telescope could finally prove its existence. | Credit: Nicholas Forder for Live Science Deep ...

A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than ...

Astronomers have discovered a brand-new world hiding out beyond Pluto. While exciting, the discovery of this new world could challenge long-standing theories of the existence of Planet Nine. In fact, ...

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...

As the world marvels at the first-ever close-up images of Pluto beamed to Earth, it is a reminder of a sharp global division: those with nine-planet childhoods vs. those now growing up in a solar ...