Mass4.15×10⁶ M☉

Schwarzschild radius1.23×10⁷ km

Inclination75°

Approaching (blue-shifted, beamed) Receding (red-shifted, dimmed)

Observer 30 Rs from the hole Drag to orbit, scroll or pinch to zoom, double-click to reset.

WebGL · –

Black Hole Lab

Light rays are traced backwards through Schwarzschild spacetime, bending around the hole. Orbits, clocks and tidal forces follow from the same geometry.

Black hole

Mass 4.15×10⁶ M☉

Schwarzschild radius1.23×10⁷ km≈ 17.7 solar radii

Disk inclination 75° Camera distance 30 Rs

Spin (Kerr frame-dragging) a = 0.90

Display

Resolution

Geodesic lab click to launch, drag to set velocity

Simulation speed 40 M/s

Infalling probe clock comparison

Drop from rest at 10 Rs

Tidal force spaghettification

Body length 2 m

Key radii

What you are seeing

Light follows null geodesics. The simulation integrates every pixel's ray through Schwarzschild spacetime, so the disk's far side appears bent over the top and a thin photon ring forms at 1.5 Rs.
Background stars are lensed: a source behind the hole is stretched into an Einstein ring, and there are extra mirrored images near the shadow edge (radius ≈ 2.6 Rs).
The disk gas orbits at up to half the speed of light. Doppler beaming brightens the side moving toward you, while gravitational redshift dims and reddens light from deep in the well. Colours follow a black-body ramp.
Particles follow the Schwarzschild effective potential. Nothing stable orbits inside 3 Rs (the ISCO). Orbits are not closed ellipses but precess, as Mercury's does, only far faster.
A falling clock ticks slower for the far observer, and the far observer never sees it cross the horizon: dτ/dt → 0. The probe itself notices nothing special there, but the tidal stretch can be lethal long before, for small black holes.

Simplifications: spin is a gravito-magnetic approximation to Kerr (not exact geodesics), the disk is a thin opaque-ish ring with a T ∝ r^-3/4 profile, and the colour scale is false-coloured from the physical inner temperature.