Gravity

Gravity is an invisible pull. You can't see it, but it's all around you, all the time. Right now, gravity is pulling you down to your chair, your bed, or wherever you're standing. That's why you don't float away.

Pretty much everything in the universe pulls on everything else. The bigger something is, the stronger its pull.

Why don't I fall through the floor?

Earth's gravity pulls you down. The floor pushes back up just as hard. You and the floor are in a little tug-of-war, and you stay right there in the middle. That's also why your toys land back on the ground when you toss them up.

Why does Earth pull on me?

Because Earth is HUGE. The bigger something is, the stronger its gravity. Earth is so big that it pulls everything near it: you, your dog, your house, and even the Moon way out in space.

Does the Moon have gravity too?

Yes! But it's much weaker. The Moon is smaller than Earth, so its pull is weaker. If you went to the Moon, you'd jump way higher than you can here. Astronauts even bounce when they walk!

Why do planets go around the Sun?

The Sun is the biggest thing in our part of space. Its gravity is super strong. It holds Earth and all the other planets close, like an invisible leash, and the planets keep zooming in big circles around it.