Gravity Sandbox

Throw planets around a star. Binary stars, the figure eight, collisions.

0/2challenges

Trails

6 bodies, t = 0

Mass of thrown bodies, log₁₀

Time warpx

Bodies: 6
Largest share of mass: 99.8%
Stable for: 0t
Total energy: -1.84e+7

The model

Newtonian gravity between every pair of bodies, F = G m₁ m₂ / r², in scaled units with G = 1 and a little softening so close passes stay finite. It is integrated with velocity Verlet, which keeps energy steady over many orbits.

Bodies that touch merge, keeping total mass and momentum. Anything that leaves far beyond the map is dropped.

Try this

Drag on empty space to throw a new body: the line sets its velocity and the dotted curve predicts its path. The figure eight is a real, if fragile, solution to the three-body problem found in 2000. Nudge it with one small body and watch it fall apart.

Two-dimensional, point masses, no relativity, no tides. Educational model, not an engineering design or validation tool.

Achievements0/2

Clockwork +40Keep five or more bodies orbiting for 60 seconds.
Accretion +30Cause five collisions in one run.

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