Cometary Dust Tail Aerodynamic Behavior (2D)
2D orbital-mechanics lab: a comet follows a Keplerian ellipse while dust and ion tails stream away from the nucleus, each grain's radiation-pressure ratio bending its path into a curved syndyne.
This 2D companion strips the 3D comet-tail scene down to the physics driving it: the nucleus sweeps along a real Keplerian ellipse, moving fastest at perihelion exactly as Kepler's second law requires, while a separate readout panel shows sun distance, orbital speed, the current dust grain's beta value and the live particle count. Dust grains are released carrying the comet's own velocity and then drift under gravity weakened by their radiation-pressure ratio, which is what bends the tail into a curve — shrink the grain size and watch the tail curve harder, while the ion tail (governed almost entirely by solar wind) stays straight regardless.
2D orbital-mechanics lab: a comet follows a Keplerian ellipse while dust and ion tails stream away from the nucleus, each grain's radiation-pressure ratio bending its path into a curved syndyne.
2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install
The dust tail curves because each grain keeps the comet's orbital velocity when it is released, then drifts under a weakened gravity (reduced by its radiation-pressure ratio, beta) — a compromise between its old orbit and the outward push, which bends the path into a smooth curve called a syndyne. The ion tail is dominated far more strongly by the solar wind, so it is pushed almost straight away from the Sun regardless of the comet's own motion.
Beta is the ratio of the outward radiation-pressure force on a dust grain to the Sun's inward gravitational pull on it. It scales roughly as 1 over the grain's radius, so smaller grains have a larger beta and are pushed outward much harder than larger grains.
This is Kepler's second law: the nucleus sweeps out equal areas in equal times, which requires it to move fastest at perihelion (closest approach) and slowest at aphelion (farthest point), driven purely by conservation of angular momentum.