Kuiper Belt Resonances: Plutinos & the 3:2 Lock with Neptune

The Kuiper Belt is not a uniform ring of debris — it is carved into sharply defined populations by Neptune's gravity. This simulator renders the Sun, Neptune and hundreds of trans-Neptunian objects on real Keplerian orbits, sized and colored by dynamical class: the classical belt, the resonant Plutinos locked in Neptune's 3:2 mean-motion resonance (the class Pluto itself belongs to), the Twotinos in the 2:1 resonance, and the eccentric scattered disk. A live readout tracks one Plutino's resonant argument φ = 3λ − 2λ_N − ϖ librating back and forth like a pendulum instead of circulating through 360° — the defining signature of orbital resonance — while sliders let you speed up time and dial the libration amplitude up or down to see gently- versus deeply-captured resonant orbits.