Orbital Resonances

Moons in step

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Io, Europa and Ganymede are locked in a 1 : 2 : 4 resonance.
• Resonant tugs keep Io’s orbit eccentric, and tides heat its volcanoes.
• Resonances with Jupiter carve the Kirkwood gaps in the asteroid belt.

Steps

1. Jupiter’s clockwork
2. Three moons in step
3. Predict the period
4. Gaps in the asteroid belt
5. Pluto and Neptune
6. Saturn’s moons in step
7. A chain of worlds