🪐 Orbit Simulator
📖 The Physics
Why doesn't the Moon fall onto Earth? It actually is falling — it just keeps missing! Gravity from the star pulls the planet straight inward, but the planet's sideways speed carries it "past" the star just as fast as it falls.
The result is that it keeps falling around the star instead of into it — that endless falling-around is an orbit. Too slow and it spirals in; too fast and it escapes.
F = G·M·m / r² (points toward the star)
Circular orbit speed: v = √(G·M / r)
Set the launch speed near the suggested value for a near-perfect circle. A bit more gives an ellipse (Kepler's first law); much more and the planet flies off forever.
🤖 Ask the AI tutor
Ask anything about this simulation and get a simple explanation.
AI can make mistakes — cross-check with your book.