Home▸Space & Astronomy▸Comet at Perihelion: Closest Approach

Comet at Perihelion: Closest Approach (2D)

Top-down 2D view of a comet's eccentric orbit: exact Kepler-equation motion sweeps equal areas in equal times (compare the two shaded wedges), speeding up near perihelion, with a correctly Sun-facing ion tail and a lagging dust tail.

Space & Astronomy2DEasy60 FPS📱 Mobile-adapted⇄ 3D version

Seen from directly above the orbital plane, a comet's headlong rush past the Sun becomes a clean geometric fact: the two shaded wedges in this simulation always cover equal area for equal time, no matter how eccentric the orbit or how close the perihelion — that is Kepler's second law, made visible rather than asserted. Drag to pan and scroll to zoom around the scene, or click anywhere near the orbit to drop the comet at that exact point and read off its instantaneous speed and tail state.

⚙ Under the hood

Top-down 2D comet orbit solving the same Kepler equation as the 3D version, but proving equal-area sweep with two fixed side-by-side wedges at perihelion and aphelion, plus a logistic sublimation-onset tail model and correct anti-sunward ion tail.

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