Mercury has long baffled astronomers because it defies much of what we know about planet formation. A new space mission ...

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 ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously ...

What is the solar system? MADDIE MOATE: The universe is vast. CHILD: Vast means really, really big! MADDIE: There are a lot of stars in our universe. And the sun is a star that gives out heat and ...