https://blackholes.fyi/explore One idea at a time, from the speed of light to merging black holes. Each page has a figure you can change. en-gb Mon, 09 Nov 2026 00:00:00 GMT https://blackholes.fyi/explore/light-speed https://blackholes.fyi/explore/light-speed Mon, 09 Nov 2026 00:00:00 GMT Light is fast, but not instant. Follow one pulse, then watch a clock that runs on light. https://blackholes.fyi/explore/spacetime-interval https://blackholes.fyi/explore/spacetime-interval Mon, 09 Nov 2026 00:00:00 GMT Two clocks, two paths, and the one number every observer agrees on. https://blackholes.fyi/explore/light-cones https://blackholes.fyi/explore/light-cones Mon, 09 Nov 2026 00:00:00 GMT Draw time up the page and 'can this reach that' becomes 'is the line steeper than forty-five degrees'. https://blackholes.fyi/explore/why-black https://blackholes.fyi/explore/why-black Mon, 09 Nov 2026 00:00:00 GMT Follow light rays past the hole and watch which ones never come back. https://blackholes.fyi/explore/what-is-inside https://blackholes.fyi/explore/what-is-inside Mon, 09 Nov 2026 00:00:00 GMT Past the horizon, distance from the centre turns into time. Three ways to see what that means. https://blackholes.fyi/explore/eddington-rate https://blackholes.fyi/explore/eddington-rate Mon, 09 Nov 2026 00:00:00 GMT Why a black hole that feeds slowly is wrapped in a faint, hot cloud, and one that feeds fast in a thin, bright disc. https://blackholes.fyi/explore/merger https://blackholes.fyi/explore/merger Mon, 09 Nov 2026 00:00:00 GMT Two black holes spiral in, merge and ring down: a supercomputer orbit, seen through lensed light. https://blackholes.fyi/explore/eating-a-star https://blackholes.fyi/explore/eating-a-star Mon, 09 Nov 2026 00:00:00 GMT A star wanders too close, is torn into a stream, and the stream falls back to feed a flare brighter than a galaxy: a simulated tidal disruption, moment by moment. https://blackholes.fyi/explore/how-we-draw-the-sky https://blackholes.fyi/explore/how-we-draw-the-sky Mon, 09 Nov 2026 00:00:00 GMT Every hole shows Earth's sky today. Here is why that is wrong, and what we are building instead.