In the solar system, nothing stands still—not even you.
You and everything else on Earth are traveling up to 1,000 miles per hour right now! That’s how fast the planet’s surface is spinning at the equator. Other planets and moons spin too. Even the Sun itself spins.
While they spin, they circle, or orbit, each other. The Moon circles Earth. Earth circles the Sun, and so do other planets, their moons, and asteroids.
Sometimes, these spinning, circling, moving objects crash into each other. Comets fall into planets. Asteroids smash into moons. Why don’t all these planets and moons and asteroids just stay where they are? The answer? It’s gravity. All objects pull other objects toward them. The more mass, or matter, an object has, the stronger its pull.
The Sun has 99.9 percent of all the matter in the solar system. Everything else makes up just 0.1 percent! That makes the Sun the most massive thing in the neighborhood. Its pull is so strong that it can even “grab” comets millions of miles away. The Sun’s gravity holds the solar system together. In fact, it’s why we even have a solar system.
