Orrery Screensaver
The Orrery screensaver places all eight planets using real orbital elements evaluated for the current date, with orbits drawn at their true inclinations. It runs in the browser with nothing to install; press ESC to exit.
How the Orrery screensaver works
The saver renders with three.js on your GPU. The library is vendored into this site rather than fetched from a CDN, and loads only when a 3D screensaver actually runs.
It reads nothing external — positions are computed in the browser from published Keplerian elements, so it works offline.
The scene resizes with the window and releases its WebGL context when the saver stops, so shuffle mode and Multi-view can cycle 3D savers without exhausting the browser's context limit.
If WebGL is unavailable the saver says so on screen rather than showing an empty black box.
A worked example
Each planet's mean anomaly advances from its J2000 epoch at its own orbital period, and Kepler's equation is solved by Newton iteration to convert that into a true position on an ellipse. The result is accurate to a fraction of a degree for dates near our own. Distances are logarithmic and this is stated rather than hidden: at true scale Neptune is thirty times Earth's distance and the inner planets would be an indistinguishable dot.
Settings & tips
- Accent and Background recolour the scene; Speed changes the pace of the motion and the camera.
- Add it to a Multi-view grid, though 3D savers are heavier than 2D ones and a few per screen is plenty.
- Press ESC at any time to leave fullscreen.
Frequently asked questions
- Why solve Kepler's equation at all?
- Because orbits are ellipses, not circles, and a planet moves faster near the Sun. The equation relates the time elapsed to the actual angle swept, and it has no closed-form solution — three Newton steps get well inside a pixel here.
- Is this accurate enough to observe by?
- No. It uses mean elements with linear rates and ignores planetary perturbations, so it is right to a fraction of a degree rather than the arcsecond an ephemeris gives. It is a picture of the arrangement, not a navigation tool.
- Does this need a special browser or plugin?
- No. It uses WebGL, which every current desktop and mobile browser supports. Nothing is installed and no plugin is required.
- Does it cost anything or need an account?
- No. Every screensaver here is free, runs in the browser and needs no sign-up.