Scientists find evidence that Mars was full of water early in the solar system's history.

A study shows that kids in a happy mood paid less attention to details.

Behind the scenes: news detective

Three scientists travel to Antarctica to explore a secret world hidden beneath the ice.

To find some of the smallest things in the universe, scientists have to think big

Particles are the building blocks of matter, and matter makes up everything you can see. The Earth and moon are matter. So is your body, your computer’s screen, even the air you breathe. Which means they’re all made of particles. Lots and lots of particles, of all different kinds, stuck together.Atoms, which used to be considered the smallest unit of matter, are made from particles too. Just how small is an atom? That’s a tricky question, since different atoms have different sizes and atoms are mostly empty space. But here’s one way to think about it: Let’s say you wanted to f...

Astronomers have defined "plutoids" as a new category of Pluto-like objects in the outer solar system.