Home▸Space & Astronomy▸Gravitational Ring Dynamics (2D)

Gravitational Ring Dynamics (2D)

2D top-down ring-particle lab: hundreds of test particles orbit a central mass under real inverse-square gravity while a perturbing moon carves resonance gaps into the ring, live.

Space & Astronomy2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

This 2D companion replaces the 3D original's static decorative rings with real inverse-square gravity: every particle is integrated live under the combined pull of the central planet and an orbiting moon, so raising the moon's mass visibly carves resonance gaps into the ring instead of just rotating a fixed particle field. Set the moon's mass to zero and the ring stays perfectly stable — proof the drift you see afterward is the moon's gravity at work, not simulation noise.

⚙ Under the hood

2D Newtonian ring-dynamics lab: test particles on circular orbits perturbed by a live-integrated planet-plus-moon gravity field, opening resonance gaps the way Saturn's Cassini Division forms.

ring dynamicsgravityorbital resonancekirkwood gapsn-bodykepler orbits

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install

Why does raising the moon's mass open gaps in the ring?

Where a ring particle's orbital period is a simple fraction of the moon's period (a resonance, e.g. 2:1 or 3:2), the moon's pull lines up at the same point in the particle's orbit again and again. Those repeated kicks accumulate instead of averaging out, pumping up the particle's eccentricity until it is ejected from that radius — the same mechanism behind Saturn's Cassini Division and the asteroid belt's Kirkwood gaps.

What keeps the ring stable when the moon mass is set to zero?

Every particle starts on a circular orbit with v = √(GM/r), the exact speed needed to balance the planet's gravity at that radius. With no moon to perturb it, that balance holds indefinitely — any drift afterward comes directly from the moon's gravity, not from integration error.