Cosmic Playground

Play with the universe. Learn the physics.

Cosmic Playground is in active beta. Expect frequent improvements as demos are hardened.

How it works

Every demo follows the same three-phase cadence. Commit to a prediction, explore the model, then reconcile what happened.

Before touching a slider, commit to a prediction. What do you think will happen?

Explore the interactive model. Drag, tweak, break it. See what the physics does.

Reconcile what happened with what you expected. That gap is where learning lives.

These three demos introduce the core orbital mechanics concepts. Work through them in order for the best experience.

Use this instrument to connect orbit shape to speed changes (Kepler 2) and connect orbit size to period scaling (Kepler 3).

Use a simple Keplerian model to visualize how the direction to a planet can briefly reverse in the sky (retrograde) even though the planet n

This pilot demo visualizes two masses orbiting a shared barycenter. It emphasizes *qualitative* relationships (how the barycenter shifts and

Station cards, instructor notes, and curated playlists for classroom use.