kepler's second law — made visible

an interactive orbit · tools & art

drag the eccentricity slider: the orbit stretches, and the planet starts to hurry past perihelion (P, its closest point) and loiter around aphelion (A, farthest). that uneven pace is kepler's second law — the line from sun to planet sweeps equal areas in equal times, so the planet cannot keep a steady speed.[1] the amber triangle is this minute's sweep; its area stays flat while the planet's speed does not.[1] click anywhere on the canvas to drop the planet at that angle — the law holds wherever you start measuring.

Sources

[1] Orbits and Kepler's Laws — NASA Science

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