But what exactly is a planet? It seems like an easy question. After all, you’re standing on one right now! But the scientific ...

Earth is far from the only celestial body in the Solar System.

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 ...

Even at a glance, the planets in our solar system are wildly diverse. Huge and small, airless and densely packed with atmosphere, they have a wide range of characteristics distinguishing them. But if ...