Kerr Black Hole Cross-Section & Frame-Dragging Dials

A 2D companion to the 3D Kerr black hole simulator: rather than a camera-rendered surface, the exact same closed-form Kerr geometry is drawn as a meridional (r, θ) cross-section — the true axisymmetric shape of the horizon and the oblate ergosphere, sliced through the spin axis — paired with a live angular-velocity graph of Ω(r) for prograde and retrograde circular orbits plus the Lense–Thirring frame-dragging rate Ω_ZAMO(r) of a "static" observer. Test particles appear as small dials spinning at their exact orbital rate directly on the curve, so you watch frame-dragging as a literal difference in spin speed rather than as motion through a 3D scene.