Earth and its neighbors orbit the sun on a relatively flat plane. But what's below this plane, and is anythign below 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 ...

Studying the orbits of thousands of exoplanets shows that large planets tend to have elliptical orbits, while smaller planets tend to have more circular orbits. This split coincides with several other ...

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 ...