Watch the planets move on their real orbits, see why they loop backwards, and see them spin on their tilted axes. Computed live on your device for the Science Centre Observatory, Jurong.
Which planets are above the horizon at SCOB this moment, and which are in apparent retrograde tonight.
Live orrery — a top-down view
Looking down on the solar system from the north. Every planet sits at its real position for the chosen date, on its true (slightly oval) orbit. Drag the slider to run time forwards or back.
Seen from the side — tilts & spin
The orrery above looks straight down. Edge-on, two things appear that a top-down view hides: how each orbit tilts out of the flat plane, and how each planet's spin axis leans.
1 · Orbital planes, edge-on. How steeply each orbit tilts relative to Earth's (the ecliptic). The solar system is remarkably flat — tilts are exaggerated ×3 here to be visible. (Pluto, a dwarf planet, tilts a dramatic 17°.)
2 · Axial tilt & rotation. Each planet spinning on its real axis (dashed) — the tilted oval is its equatorial (rotational) plane, and the white spot shows the turn. Labels give the true rotation time.
Why planets seem to go backwards
Usually a planet drifts slowly eastward against the stars, night after night. But around the time Earth overtakes it, it appears to stop, loop westward for weeks, then resume. Nothing actually reverses — it is a trick of our moving vantage point. Press play and watch the two views together.
Top-down — the cause. Earth (inner, faster) sweeps past the planet; watch the orange sight-line's tip swing back across the distant stars as we overtake it.
As seen from Earth — the effect. The planet's real track across the sky; it loops backwards (red) exactly while we overtake it.
The horizontal axis is position along the zodiac (ecliptic longitude); the vertical axis is how far the planet strays above or below the ecliptic. The ancient Greeks needed extra "epicycles" to explain these loops; a Sun-centred solar system makes them fall out for free.
Sun, Moon and planet positions are computed on your device with the shared SCOB astronomy engine (P. Schlyter's method), validated to arc-minute accuracy. Retrograde windows are derived live from the same engine; spin speeds in the tilt diagram are compressed for visibility. About & credits ·