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

A new study suggests mysterious water worlds may be manufacturing their own oceans through chemical reactions deep within ...

Far beyond Neptune, something massive may be warping the orbits of distant worlds. This film follows the scientists chasing ...

Our solar system now, once again, officially consists of only eight planets. Although largely debunked, speculation continued ...

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 are investigating a potential hidden planet, dubbed Planet Y, far beyond Neptune. Its gravitational pull is suspected to be causing unusua ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics, but collectively believed to be ...

Astronomers now understand that water-rich planets can form internally, even close to stars. A new study reveals that ...

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 ...

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 dubbed ...