The Live Orrery

What you are seeing

An orrery is a working model of the solar system. This one is not a fixed picture: it places each planet where it actually is on the date shown, worked out live from the same astronomy engine the rest of the site uses. Drag the time slider, or press Play, and the planets move along their real orbits.

Two views of the same sky

The Sun-centered (heliocentric) view is the true layout: the Sun sits at the middle and the planets, Earth among them, circle it. This is the map astronomers use, and it is where alignments and the Venus-Earth dance are easiest to see.

The Earth-centered (geocentric) view puts Earth in the middle and arranges the Sun, Moon and planets by where they appear in our sky, around the ring of the zodiac. It is what the sky looks like from here. The planets are drawn on evenly spaced rings rather than at true distance, because this view is about direction, not depth.

Turn on Trails

Switch on Trails and press Play to leave a fading path behind each planet. In the Sun-centered view the trails simply trace the orbits. In the Earth-centered view something stranger appears: as Earth overtakes an outer planet, that planet seems to stop, slip backward, and loop, the famous retrograde motion. It is not the planet reversing; it is us passing it on the inside track.

Let it run for several years in the Earth-centered view and watch Venus. Each time Venus passes between Earth and the Sun it does so a little further around the zodiac, and over eight years those passes trace a near-perfect five-petaled rosette, the pattern explored on the Venus page.

About the scale

Space is mostly empty. Pluto is about a hundred times farther from the Sun than Mercury, so a true-to-scale map would crush the inner planets into a single dot. The all-planets view therefore uses a square-root distance scale so every body is visible at once; switch to Inner system for a closer, more honest spacing of Mercury through Mars. Either way the angles around the Sun are real. The map is flattened onto the plane of Earth's orbit, which ignores the small tilts of the other orbits.

We include Pluto as the outermost body. The International Astronomical Union reclassified it as a dwarf planet in 2006, but it remains a favorite, and its orbit is plotted here in full. Pluto's path is so stretched that for about twenty years, from the late 1970s to the late 1990s, it actually rode closer to the Sun than Neptune, which you can watch by scrubbing back to the 1980s and 1990s.

Frequently asked questions

What is an orrery?

An orrery is a working model of the solar system, sometimes called a solar system model or simulator, that shows where the planets are. This one is computed live: instead of a fixed diagram it places each planet at its real position for the date you choose, and animates the orbits when you press Play.

What is the difference between the heliocentric and geocentric view?

The heliocentric (Sun-centered) view puts the Sun in the middle with the planets, including Earth, orbiting it; this is the true layout of the solar system. The geocentric (Earth-centered) view puts Earth in the middle and shows where the Sun, Moon and planets appear in our sky around the zodiac. This orrery lets you switch between the two.

Can I see the planets' positions for a past or future date?

Yes. Drag the time slider or use the date picker to jump to any date from 1700 to 2200, and the orrery redraws the planets at their positions for that moment. Press Play to watch them move, and turn on Trails to trace retrograde loops and the eight-year Venus pattern.

Are the positions accurate?

Yes. Positions come from the Astronomy Engine library and are good to well within a degree for the planets across the years this tool covers. The orrery is a flattened top-down view, so it shows each planet's direction and distance in the plane of Earth's orbit, not the slight up-and-down tilt of its real orbit.

Why do the planets only go around, never up or down?

Because all the planets orbit the Sun in nearly the same flat plane. A top-down map captures almost everything; the small tilts are why eclipses and transits are occasional rather than monthly, a story told on the eclipses and lunar nodes pages.

What is retrograde motion?

It is the apparent backward loop a planet traces against the stars when Earth overtakes it (for outer planets) or it overtakes Earth (for inner ones). Turn on Trails in the Earth-centered view and play forward to watch it happen. Nothing actually reverses; it is an effect of our moving viewpoint.