Every planet position is computed for the displayed moment with the Astronomy Engine ephemeris — the same math used by astronomy software. Earth's Moon and Jupiter's four Galilean moons follow their true computed orbits; the other moons follow their real periods and distances with approximate starting phases. Distances and sizes are gently compressed so everything stays visible — space is mostly empty at true scale.
The eclipse menu lists every solar eclipse from 1980 to 2060. The shadow on Earth is computed from the actual Sun–Moon geometry at the displayed time: the soft gray disc is the penumbra (partial eclipse), the dark core is the umbra (total or annular eclipse), drawn at its true location and size.
Planet textures: Solar System Scope (CC BY 4.0). Io, Europa, Ganymede, Callisto maps © Björn Jónsson (non-commercial use). Saturn & Pluto system moon maps: NASA/JPL/Space Science Institute, NASA/JHUAPL/SwRI, USGS Astrogeology (public domain). Uranian moons: Celestia Project. Smaller moon maps: Stellarium.
Tap a planet or its label to fly to it. Pinch or scroll to zoom — close-ups load sharper imagery automatically.