Black hole live wallpaper for Mac
Light, bent round a black hole.
A supermassive black hole and its glowing disc, rendered live behind your desktop icons. Its gravity bends the far side of the disc up over the shadow and down under it, and the starlight behind it into arcs.
Animated in real time · One-time purchase, every wallpaper included · macOS 12 or later, Apple silicon and Intel
An Apple-verified version is coming soon as a free update. Until then, macOS asks you to confirm the app once, the first time you open it, and your download page shows how.
Views
Three framings of the black hole.
The show moves through them in turn, each held for over a minute while the camera drifts round. Every picture here is a frame from the animated wallpaper.
Almost edge-on
The disc seen nearly side-on. Light from its far side is bent up over the shadow and down under it, and a thin bright ring hugs the shadow’s edge.
Closer in
The camera nearer the hole and a little higher, the disc running off both sides of the screen.
From higher above the disc
From higher up, the disc and its bent image wrap round the shadow.
What you see
Its light is traced through curved space.
For every pixel, the wallpaper sends a ray out from the screen and steps it through the hole’s gravity up to 180 times, every frame, picking up the disc’s glow where the ray crosses it and the starlight where it ends up, or leaving the pixel black where the hole keeps it. The shadow, the ring of light round it and the bent disc all come out of that.
The bending follows general relativity for a black hole that does not spin, the solution Karl Schwarzschild found in 1916. The disc is drawn for the picture: a layer of glowing gas from 2.6 to 12 times the hole’s Schwarzschild radius, its inner gas going round faster than its outer, white-hot at the inner edge through gold and orange to a deep red rim.
The show moves through three framings, each held for over a minute while the camera drifts slowly round, which walks the bent starlight round behind the hole.
Traced every frame
Each pixel’s light is stepped through the hole’s gravity, so the shadow, its ring and the bent disc are worked out live.
Three framings
Almost edge-on, closer in, and from higher above the disc, each held for over a minute as the camera drifts round.
The heaviest to draw
The black hole asks more of the graphics chip than the planets do. On an older Mac, pick Light quality or 15 frames a second for it.
Made to stay on
Made to run all day, quiet when hidden.
Under your icons
It sits beneath the desktop icons, widgets and the Dock. Clicks go straight through to the desktop, and it never takes focus from what you are doing.
Pauses on its own
When windows cover the desktop, a full-screen app is open, the screen locks or sleeps, or a screensaver starts, it stops drawing until the desktop shows again.
Easy on the battery
On battery or in Low Power Mode it drops to 15 frames a second, or pauses, whichever you pick. Its usual pace is 30.
Pick your world
The other live wallpapers.
One purchase gets every one of them, over 80 in all, and you switch between them from the menu bar.
Questions
Good to know.
Is it a real black hole?
Its light bending is real: it follows general relativity for a black hole that does not spin, so the shadow and the way the disc and the stars bend round it are what that theory says you would see. The disc itself is drawn for the picture, with its colours running from white-hot to deep red by choice.
Will it slow my Mac down?
The black hole is the heaviest wallpaper to draw, since every pixel steps its light through the hole’s gravity up to 180 times a frame. On an older Mac it may run less smoothly than the planets, so pick Light quality or 15 frames a second. Like every wallpaper, it stops drawing whenever the desktop is covered or the screen locks or sleeps.
Is there a black hole screensaver too?
Yes. The same black hole is one of the shows in the Solar System screensaver for Mac, Windows and Linux, and the desktop bundle has the screensaver and the live wallpapers together.
Do I only get the black hole?
One purchase of $2.99 is the whole app: every planet, the Sun, the Moon and Pluto, the Milky Way, the black hole, the ISS and the grand tour, over 80 wallpapers in all.
Which Macs does it run on?
Any Mac on macOS 12 Monterey or later, Apple silicon or Intel. Everything it shows is inside the app, so it runs offline.