Why do planets go around the sun?
Every second of every day, Earth is falling. Right now, as you read this, our entire planet is plummeting through space at nearly 70,000 miles per hour. And yet somehow, we never hit the ground. In fact, we've been falling for four and a half billion years, and we're going to keep falling forever. This is the secret of why planets orbit the sun.
Here's the trick: Earth isn't falling straight down toward the sun. It's falling sideways while it falls forward. Imagine you're on a skateboard rolling past a drain in the street. Gravity pulls you toward the drain, but you're moving so fast sideways that you curve past it instead of dropping straight in. Earth does the same thing with the sun, except the "skateboard speed" is 70,000 miles per hour.
