Sep 2026 →
An interactive black hole simulator worked out from the physics, made with my son.
Photograph: Stef and Oren Lewandowski
- When
- Sep 2026 →
- Stack
- TypeScript, React, three.js, Cloudflare Workers
Blackholes.fyi is a black hole you can move around in a web browser, drawn in real time and worked out from the physics. I'm making it with my son, Oren: he co-writes the words and checks the physics, and I make the pictures. We started on 13 September 2026.
Most of each picture comes from tracing light. For every pixel, a GPU shader follows a ray backwards from the camera through the Kerr metric (the spacetime around a spinning black hole) to find where it came from. Where a part is too heavy to compute in a browser, or the physics isn't settled, the site says so and labels it modelled or chosen.
The home page starts at Earth, the Sun and the planets, then pulls back to 3C 273, a real black hole. From there it walks through what you're looking at. The accretion disc is the flat ring of hot gas circling the hole, and the shadow is the dark patch where no light gets back to us. Gravity bends light round the hole, so the far side of the disc shows twice and the stars behind are pulled into rings.
A gallery holds real black holes, each drawn with its published mass, spin, distance and accretion rate (how fast it takes in gas), from Sagittarius A* at the centre of our galaxy to TON 618, among the heaviest known. Other pages follow a star being torn apart and two black holes merging.
Oren signs off each release before it goes live.
Pictures
After Earth, the Sun and the planets, a real black hole: 3C 273, with the planets' orbits drawn to scale inside its shadow.
Light from the far side of the accretion disc bends over the top of the hole and under it, so the same gas shows twice.
The stars behind the hole, bent into rings by its gravity.
Close to the hole, its shadow fills the view.
Gas coming towards us shifts blue and brightens; gas going away shifts red and dims.
A grid laid over the sky, bent by the hole's gravity.
Sagittarius A*, the black hole at the centre of our galaxy.
Cygnus X-1, a black hole feeding on the wind of a giant blue star.
GRS 1915+105, which fed close to the Eddington limit (the fastest a black hole can take in gas before its own light pushes the gas away) for 26 years, throwing out jets.
TON 618, a quasar (a black hole feeding so fast it outshines its galaxy) and among the heaviest black holes known. Its shadow is 990 billion km across.
A star torn apart. Close to the hole an orbit does not close, so the returning stream crosses itself.
Fed slowly, the gas puffs up into a hot cloud rather than a thin accretion disc.
3C 273's shadow is big enough to cover Saturn's orbit.
Around the same time
Earlier in data art: Year of Colour.