Model

Orrery

The eight planets on their real orbits, at the real date. Each body is placed from its own Keplerian elements rather than from a drawn ellipse, so the spacing and the timing are the ones the sky actually keeps. Drag to orbit the system, scroll to close in, and let the clock run to watch the inner planets pull ahead.

How the model works

Positions come from Keplerian elements propagated to the current Julian date.
Orbits are drawn from the same elements, so a body always sits on its own path.
Body radii are exaggerated — at true scale the planets would be invisible against a system this wide.
The Sun sits at the origin and is not to scale with the orbits.

Elements

Orbital elements are the standard mean elements for each planet at the current epoch. The archive keeps them with the orbit runtime it already uses for the satellite tracker, so one propagation code serves both views.

Runtimes and licences are listed on the notices page.