Planets in our solar system move in orbit around the Sun because of two counteracting laws, inertia and gravity. Inertia makes the planets move forward in a straight line while the gravity of the Sun pulls the planets towards itself. The combination of inertia and gravity makes the planets travel in a circle around the Sun.
Click/tap the Sun to watch the planets moving in orbit. Click/tap the button to stop.

© Dan Beardshaw, 2026