Orrery Screensaver
The Orrery screensaver is a live clockwork model of the solar system, showing the eight planets at their real positions for today as they orbit the Sun. It is computed on your device from current planetary elements, needs no feed, runs in your browser, and ESC exits.
How the Orrery screensaver works
The saver uses the standard Keplerian orbital elements for the eight planets and advances them to today's date with their known rates of change.
For each planet it solves Kepler's equation to find exactly where on its ellipse the planet sits right now, relative to the Sun.
The Sun is drawn at the centre with the planets as colored dots on their orbits, scaled so the inner planets aren't cramped and Neptune still fits.
A time-lapse control lets you fast-forward, watching the planets pull ahead of one another at their real relative speeds.
A worked example
The inner planets sweep quickly while Jupiter and Saturn barely creep, all at their genuine positions for today's date. Turn up the time-lapse and months fly by, the faster inner worlds lapping the slow outer giants exactly as they do in reality.
Settings & tips
- Time-lapse sets how fast the model fast-forwards through time.
- Show orbit paths draws the elliptical orbits.
- Planet labels toggles the planet names.
Frequently asked questions
- Are the planet positions real?
- Yes. They're computed from the planets' actual orbital elements for today's date, so the layout matches where the planets really are around the Sun.
- Does it need a connection?
- No. Everything is calculated locally from built-in orbital data, so it runs fully offline.
- Is the scale realistic?
- The angles and relative motion are real, but orbit radii are compressed so the inner planets and Neptune all fit on screen together.
- How is this different from Solar Systems?
- Solar Systems is an artistic generative animation; the Orrery shows the eight real planets at their true positions today.
- Is it free?
- Yes — free, no download, no key, in your browser.