Newtonian gravity
Every body attracts every other body according to mass and inverse-square distance.
Truuts experiment
Three-Body Simulation
A continuously evolving gravitational system where three bodies create unstable orbits, temporary captures and unpredictable trajectories.
About the experiment
L3 models three celestial bodies acting on one another through Newtonian gravity. Unlike a two-body orbit, the system has no general closed-form solution: its future must be calculated step by step.
The experiment begins with a binary pair and a third body entering their shared field. Transfers, close encounters and escapes emerge from the same small set of physical rules.
Interactive demo
Change the initial-condition preset, pause the system or restart it to observe how small differences produce radically different paths.
Technical concepts
Leapfrog integration
Velocity Verlet alternates velocity and position updates to preserve orbital energy more reliably.
Physics substeps
Eight calculations per visual frame produce an effective 240 Hz physics model.
Softening
A small epsilon prevents singular forces and numerical explosions during very close encounters.
Chaotic sensitivity
Small changes in mass, position or velocity can lead to completely different long-term trajectories.
Dynamic framing
The camera follows the system’s changing center and scale while trails retain its recent history.