How to Explore Sagittarius A* Star Orbit 3D Explorer - Step by Step
The Sagittarius A* Star Orbit 3D Explorer starts as soon as the page loads: drag to orbit the view, scroll or pinch to zoom, and watch S2's real ellipse render around the black hole marker at its focus. Everything renders on your own device - no install, no account.
Drag the time slider
Drag the time slider in the Sagittarius A* Star Orbit 3D visualizer to set S2's position anywhere in its 16.05-year orbit - the facts panel updates with the current year in the cycle and S2's distance from Sagittarius A* at that point.
Press Play and watch pericenter
Press Play and watch S2 sweep through pericenter, its closest approach - the star visibly speeds up over that short stretch of the ellipse, the same real physics (Kepler's second law) behind its measured ~7,700 km/s closest-approach speed.
Read the facts table
Read the facts table beside the scene: orbital period, semi-major axis, eccentricity, pericenter distance and speed, Sgr A*'s mass as measured from this very orbit, and the distance to the Galactic Center.
Compare pericenter and apocenter back to back
Compare pericenter and apocenter back to back by dragging the slider to each extreme in turn - the same ellipse, the same star, but a speed difference of roughly twenty-to-one between the two ends of the orbit.
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