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Why Do Planets Orbit Stars?

This Science Minute was researched and written by Soren M., Trumansburg.

Orbits and more orbits! Why in the world do planets orbit stars? Planets orbit stars because of gravity. Gravity is the force that pulls you to a planet. Gravity shapes the orbits of planets. The gravity of stars pulls on nearby planets.

Planets want to move in straight paths. If there’s a star near the planet, the star’s gravity will pull the planet towards the star. The planet continues to travel forward, but the star’s gravity holds onto the planet making it go in circles. This is an orbit.

Imagine a tetherball game where a ball is attached to a rope attached to a pole. The ball represents a planet, the pole represents a star, and the rope represents the star’s gravity. When you throw the ball it doesn’t travel straight because the string pulls it into a circle, like an orbit.

So think of the solar system as a tremendous tetherball game!