Instrument · real-time gravitational lensing
The Black Hole
Light bent by curved spacetime, traced pixel by pixel, live on your GPU.
This is not a swirl painted onto a texture. Every pixel you see is a camera ray marched through the curved spacetime around a Schwarzschild black hole, its path bent toward the mass by the same photon-orbit equation the geometry demands. The starfield behind the hole is genuinely lensed — smeared into arcs, doubled, and wrapped into an Einstein ring around the shadow. A thin bright photon ring glows at one and a half Schwarzschild radii, where light can orbit. A hot accretion disk in the equatorial plane is coloured by a blackbody temperature gradient, brightened and blue-shifted on the side rotating toward you by relativistic Doppler beaming, and — because the rays genuinely bend — its far side arches up over the top of the hole. Drag to orbit, scroll to zoom, dive toward the horizon, and flip the lensing off to see exactly what it was doing. This is the crown of the collider's visual shelf: real physics, rendered in real time.
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Gargantua-class shadow
Genuine geodesic lensing: the ring you see is the photon sphere at 1.5 r_s, the shadow is 2.6 r_s across, the disk starts at the ISCO (3 r_s).
Honest caption. Two things you can hear, both synthesized in your browser — no audio files, no recordings. Perseus B♭ evokes NASA's 2022 sonification of the real Perseus-cluster black hole: pressure waves it launches into the surrounding gas carry the deepest note ever detected — a B♭ about 57 octaves below middle C (one oscillation takes ~10 million years). NASA re-synthesized it up ~57–58 octaves to be audible; we reproduce a drone at that scaled B♭ (~56.6 Hz), it is a re-creation of the pitch, not NASA's audio. This sim's own state maps this page's controls to sound — bigger mass = deeper; higher spin/inclination brighten the Doppler shimmer; the accretion disk hums a filtered noise-bed. It sonifies the picture on screen, not a real black hole. No CERN / EHT / NASA affiliation.
Drag on the sky to orbit · scroll / pinch to zoom · space = play/pause · try inclination near 88° to see the disk arch over the top, then flip Lensing off to compare.
Read this before you screenshot it
This is a real geodesic ray-tracer, and it says so honestly. Each pixel is a photon
path integrated through the Schwarzschild metric — the exact spacetime of a
non-spinning black hole — using the standard light-bending equation
d²u/dφ² + u = 3·M·u² (with u = 1/r, in
geometrized units where G = c = 1). The lensing, the Einstein ring,
the photon ring at 1.5 rs, the capture of any ray with impact parameter
below bcrit = 3√3·M, and the disk's far side arching over the shadow are
not drawn in by hand — they fall out of integrating that equation. This is genuine
gravitational lensing, not a swirl texture.
But it is a real-time approximation, and the honesty cuts both ways. The integration uses a finite number of march steps (so grazing rays near the ring are approximate); the disk uses a simplified analytic emission model (a blackbody temperature ramp and a Doppler/redshift factor), not full radiative transfer; there is no numerical relativity, no magnetohydrodynamics, no ray-traced volumetrics. The spin control is an honest approximation that warps the disk and shifts the brightness asymmetry — it is not a true Kerr metric (no real frame-dragging, no ergosphere, no asymmetric shadow). This is an illustration built on the actual physics, not a research GRMHD simulation of the kind that produced the EHT image of M87*. It makes no falsifiable claim.
The falsifiable science on this site lives next door and is gated: the parameter-free a₀ derivation against 175 SPARC galaxies, the particle-scale predictions against CODATA, and the live MOND-vs-Newton galaxy sandbox. Those make claims that can die. This page makes none. Its only job is to make real, curved spacetime feel as astonishing as it is. Consistency, not proof; and here, plainly, wonder.
The physics you're looking at
- The shadow. The pure-black disk is every ray captured by the hole — anything with impact parameter below bcrit. It is bigger than the horizon because gravity bends grazing light inward.
- The photon ring. The thin bright ring hugging the shadow is light that looped one or more times around the photon sphere at 1.5 rs before escaping to your eye. Flip Photon ring to emphasise or calm it.
- The Einstein ring & lensed stars. Background stars directly behind the hole are wrapped into a ring; off-axis stars are doubled and smeared into arcs. Toggle Lensing off to watch the sky snap back to flat — the clearest way to see what curvature does.
- The disk arching over the top. Because rays bend, you see the underside of the far side of the disk lifted up above the shadow, and the top of the near side wrapping under — the iconic Interstellar look. Best at high inclination.
- Doppler beaming. The disk side rotating toward you is brighter and bluer; the receding side is dimmer and redder. Toggle Doppler beaming to see the asymmetry appear and vanish.
- Gravitational redshift. Light climbing out from near the horizon loses energy — the disk reddens and dims as it approaches the inner edge.