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Dark Matter Halo Around a Galaxy — Rotation Curve (2D)

A top-down 2D galaxy of orbiting stars with a live rotation-curve plot — pan and zoom the disk, toggle the dark-matter halo, and watch the curve fall off Keplerian or stay flat.

Cosmology2DEasy60 FPS📱 Mobile-adapted⇄ 3D version

A simplified top-down view of a spiral galaxy: stars orbit on circles whose speed is set by the enclosed mass of a visible exponential disk plus an adjustable spherical dark-matter halo. Pan and zoom the disk, click any star to read its orbital radius and speed, and toggle the halo to compare the observed flat rotation curve against the Keplerian falloff expected from visible mass alone.

⚙ Under the hood

A top-down 2D galaxy with a live rotation-curve plot — pan and zoom the disk, click a star, and toggle the dark-matter halo to see the curve switch between flat and Keplerian falloff.

dark-mattergalactic-rotationastrophysicsastronomyhalloween

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