Trace the shapes of gravity. Adjust the eccentricity to move between a circular orbit, an ellipse, and an escape trajectory — with the star at the focus.
Kepler Orbit StudioLive
two-body gravity · conic-section orbits
Controls
Set the eccentricity to trace Kepler's orbits — a circle, ellipse, or (past e=1) an escape hyperbola. The star sits at the focus. Drag the planet on the canvas to reposition its starting point and reshape the orbit.
Reading this result: At e=0.60 the orbit is an ellipse with the star at one focus. The planet sweeps equal areas in equal times, so it runs fastest at perihelion and slowest at aphelion. A higher e means a more elongated ellipse. The period grows as a^(3/2) (Kepler's third law), so a=140 sets the year length.
Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.
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How it works
A test body moves under an inverse-square gravitational pull toward a central star placed at the focus. The initial speed is set from the eccentricity so the orbit closes into the conic sections Kepler described: circle, ellipse, parabola, and hyperbola.
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Ask the AI about this model
The math, the assumptions, real-world uses, or a code translation — explained for this exact simulation.
Is this orbital mechanics simulation tool really free?▾
Yes. Kepler Orbits runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?▾
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?▾
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?▾
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.