LIGHT, BENT TO ITS LIMIT.
Preparing the GPU ray tracer.
WHAT IS BEING SIMULATED?
Each pixel follows a numerical null geodesic through Kerr spacetime—the geometry of an isolated, rotating, uncharged black hole. Spin changes both the light paths and the innermost stable prograde circular orbit (ISCO).
The first intersection with an opaque, infinitesimally thin equatorial disk emits the light you see. Circular orbital motion and gravity set the observed/emitted frequency ratio, g. Bolometric brightness is scaled by g⁴. Turning off frequency shifts sets g to one; it keeps the curved paths.
The emissivity profile, warm palette, radial bands, exposure, and glow are illustrative choices. This is not a fluid simulation, a Novikov–Thorne spectrum, or a model of a specific observed black hole. No returning radiation, disk thickness, jets, magnetic fields, or evolving spacetime are included.
The observer is at infinity. Framing changes image-plane coverage, not observer distance. M here means GM/c²—half the Schwarzschild-radius unit used in v0. The disk ends at 25 M. Dragging changes inclination; the disk is axisymmetric, so orbiting its axis would not change the image.
A bounded GPU integrator trades speed for detail. It cannot resolve infinitely thin higher-order images; unresolved rays stay dark. Balanced and Sharp change pixel resolution, not the integration method. Rendering pauses when the view is unchanged.
Equations, validation, and sources ↗Numerical validation report ↗