Full-send power with a stability guard.Launch mega-worlds, forge 256-ball clouds, spin vortices, or smash a cataclysm—without fusing any ball.
Your universe starts here.
Choose Launch, then click and drag. A longer arrow means more speed.
Object 001
Rock
100 length units
SPEED
SHIFT drag to pan60 FPS
Ultra power. Guarded stability.
There is no starting star, central pull, fixed orbit, invisible wall or automatic deletion. Every object feels gravity from the others. Balls can form clumps, rings and orbiting systems, but they never fuse.
THE CONTROLS
1 Inspect · drag empty space to pan2 Launch · drag to fire an object3 Cloud · launch up to 256 balls4 Balls · paint separate balls5 Pulse · blast, pull, spin or brake6 Erase · click an objectSPACE Pause or resume. Take one small simulation stepF Fit all objects into viewCTRL/⌘ Z Undo the last editMouse wheel / pinch · zoomRight drag / two fingers · pan
Power tools pause time while you aim. Ball painting leaves collision-safe space. Pulse is instantaneous: it can blast, pull, add clockwise or counterclockwise motion, or stabilize velocities, but it never leaves a hidden force behind.
WHAT THE PHYSICS DOES
The engine advances motion with kick–drift–kick integration and an adaptive timestep. The selected engine profile controls when exact equal-and-opposite gravity switches to a Barnes–Hut tree with net-force correction. A spatial contact solver keeps hundreds of solid balls responsive.
aᵢ = G ∑ⱼ mⱼ (rⱼ − rᵢ) / (|rⱼ − rᵢ|² + ε²)³ᐟ²
Hard impacts fracture sufficiently large balls. Fracture power changes the threshold and chain depth; a strict per-step budget, cooldowns, mass conservation and a body cap prevent runaway breakups.
ULTRA EDITION LIMITS
The engine supports up to 800 separate bodies, launch masses to 1,000,000 units, gravity to 500, launch speeds to 700 and pulses to 600. Large-system trail and field rendering automatically reduce detail before they can lock up the page.
STABILITY GUARD
The game keeps a recent stable checkpoint, pauses on invalid motion or drawing failure, and offers recovery. Undo restores the state before your most recent edit. Resize guards also prevent a hidden or tiny preview frame from collapsing the camera scale.
WHAT IS STILL SIMPLIFIED
This is a 2-D, scaled-unit N-body sandbox, not a research-grade planet-formation model. Tree gravity is approximate. Bodies are ideal spheres; gas pressure, detailed deformation, fusion, thermal evolution and motion out of the screen are not simulated.