Simple Orbit Simulator

Simple Orbit Simulator brings the elegance of Einstein's general relativity to your fingertips. Watch two celestial bodies dance under the influence of gravity — not as a textbook approximation, but as a true Schwarzschild geodesic simulation — the same physics that governs real planets, stars, and black holes.

Real Physics, Visually Beautiful

Unlike typical orbit simulators that use Newtonian gravity, Simple Orbit Simulator traces actual curved-spacetime paths. Every orbit is a genuine geodesic of the Schwarzschild metric. The result: Mercury-style perihelion precession that slowly paints a rosette pattern on screen, gravitational time dilation that deepens as the planet plunges toward the star, and event horizon dynamics that are physically meaningful — not just decorative.

Black Hole Mode

Switch to Black Hole Mode and watch a supermassive compact object warp the simulation. The event horizon, photon sphere, and innermost stable circular orbit (ISCO) become visible boundaries. Push the planet too close and it crosses the point of no return. Accretion disk glow and a dynamically warped spacetime grid make the physics viscerally tangible.

Full 3D Orbits

Tilt the orbital plane with the inclination slider and drag the canvas to rotate the camera freely. Horizontal drag changes the azimuth — spinning the scene left and right. Vertical drag changes the elevation — from a top-down view to edge-on. A circular orbit becomes an ellipse, a line, or a spiral rosette depending on your viewpoint. Physics is computed in full three-dimensional space.

Live Relativistic Metrics

Track real-time data as the simulation runs:
• Gravitational time dilation factor
• Accumulated proper time of the orbiting body
• Lorentz gamma factor
• Orbital velocity as a fraction of the speed of light
• Perihelion precession angle in degrees
• Orbits completed

Explore and Experiment

Adjust star mass, planet mass, and orbital distance with intuitive logarithmic sliders. See how increasing the star's mass deepens the gravitational well. Increase separation and watch relativistic precession shrink as GR effects fade with distance. Combine an inclined orbit with Black Hole Mode for a dramatic 3D plunge trajectory.

Built for Clarity

Every design decision prioritises understanding over complexity. The simulation uses scaled constants so relativistic effects are visible at screen scale — preserving all qualitative behaviour predicted by general relativity in a form humans can actually see.

Simple Orbit Simulator is for students, educators, curious minds, and anyone who has ever looked up at the night sky and wondered what holds it all together.