Event Horizon – Black Hole Lensing Simulator

Event HorizonReal-time black hole ray tracer

Schwarzschild radius– Camera distance– Resolution / FPS–

Clock rate at camera– 1 h here equals– Circular-orbit period– …on the orbiter's clock– Star orbit (far / own clock)– Disk edge redshift √(1−rs/r)–

What am I looking at?

Lensing. Every pixel is a light ray traced backwards from the camera through curved space. Gravity bends it, so the starry sky and the far side of the disk are smeared around the hole. The black shadow (about 2.6 r_s across) is where rays fall into the horizon.

Disk image. The disk lies flat, yet you see it arched over and under the hole: light from its back side is bent up to the camera (the Einstein-ring-like halo). Thin photon rings hug the shadow edge, made by light that orbited the hole once or more.

Colour & brightness. Hotter gas is bluer. Gas moving toward you is Doppler-blueshifted and beamed (brighter); the receding side is dimmed and reddened. Light climbing out of gravity is redshifted, so the inner edge is dimmer than a naive view.

Time. Deep in the potential well clocks run slow. The readout shows how fast the camera's clock ticks versus a distant observer, and how long a circular orbit takes at your distance for your mass setting.

Sim notes. Schwarzschild geometry with an added frame-dragging term for spin (an approximation of Kerr, not a full solver). Jets are an artistic extra. All sky and disk detail is procedural.

Drag orbit · Scroll / pinch zoom · release to coast · try the presets

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