Scrub orbital phase from 0% to 99%, then play or pause as Pluto and Charon circle a shared barycenter that sits outside Pluto - both tidally locked to each other.
NASA New Horizons and JPL figures put Pluto's mean radius at 1188.3 km and Charon's at 606 km. Masses are about 1.303e22 kg and 1.586e21 kg (~8.2:1). Center-to-center separation is ~19,591 km; the barycenter sits ~2,110 km from Pluto's center - outside Pluto's surface. The synchronous period is 6.387 days and both bodies are tidally locked.
Drag to orbit and scroll or pinch to zoom. Press Play or Pause, Reset, or scrub orbital phase. For the ordinary planet-moon case where the barycenter sits inside the primary, see the Earth-Moon Barycenter 3D Explorer; for a dwarf-planet size lineup see the Dwarf Planet Comparison 3D Explorer.
Pluto-Charon Double Planet 3D Explorer
This browser explorer shows Pluto and Charon as a near double-planet pair: both worlds orbit a shared barycenter that sits outside Pluto, and both stay tidally locked so the same faces keep looking at each other.
NASA New Horizons and JPL figures put Pluto's mean radius at 1188.3 km and Charon's at 606 km. Masses are about 1.303e22 kg and 1.586e21 kg - a mass ratio near 8.2:1. Center-to-center separation is about 19,591 km. The barycenter lies about 2,110 km from Pluto's center, which exceeds Pluto's 1188.3 km radius, so the barycenter is outside the primary. The synchronous orbital period is 6.387 days.
- Scrub orbital phase across a full mutual orbit
- Play, pause, or reset the tidally locked dance
- Read published radius, mass, separation, and barycenter figures in the facts panel
- Compare with sibling pages for Earth-Moon (barycenter inside Earth) and dwarf-planet size comparison
- Drag to orbit the camera, scroll or pinch to zoom
- Runs fully in the browser with the vendored three.js engine - no account, no upload
Orbital-mechanics teachers use the outside-Pluto barycenter to show why this pair is the classic near double-planet case. Readers who already know Earth-Moon geometry use this page for the mutual lock and exterior barycenter that the Earth-Moon explorer does not teach.
| Figure | Published value |
|---|---|
| Pluto mean radius | 1188.3 km |
| Charon mean radius | 606 km |
| Pluto mass | 1.303e22 kg |
| Charon mass | 1.586e21 kg |
| Mass ratio Pluto:Charon | ~8.2 : 1 |
| Mutual separation (center-to-center) | ~19,591 km |
| Barycenter from Pluto center | ~2,110 km (outside Pluto) |
| Synchronous orbital period | 6.387 days (both tidally locked) |
For the ordinary planet-moon case where the barycenter sits inside the primary, open the Earth-Moon Barycenter 3D Explorer. For a dwarf-planet size lineup, open the Dwarf Planet Comparison 3D Explorer.
Everything renders on your device with WebGL. The 3D engine loads once (about 0.7 MB) and is cached; no scene data is sent to a server.
This is an educational approximation - on-screen distances are compressed for readability, while radii and barycenter location use published NASA New Horizons / JPL figures. It is not a gravity integrator.
Frequently Asked Questions
Why is Pluto-Charon called a double planet?
The shared barycenter sits outside Pluto (~2,110 km from Pluto's center vs a 1188.3 km mean radius), and both bodies are tidally locked with a 6.387-day synchronous period. That exterior barycenter plus mutual lock is the classic near double-planet geometry.
How is this different from the Earth-Moon barycenter page?
In the Earth-Moon system the barycenter sits inside Earth. Here the barycenter is outside Pluto. Open the Earth-Moon Barycenter 3D Explorer for the ordinary planet-moon case.
How is this different from dwarf-planet comparison?
Dwarf-planet comparison teaches relative sizes in a lineup. This page teaches mutual orbit, tidal lock, and an outside-primary barycenter. Open the Dwarf Planet Comparison 3D Explorer for the size lineup.
Are the on-screen distances to scale?
No. Distances are compressed so both worlds and the barycenter stay readable. Radii, masses, separation, and barycenter location still use published NASA New Horizons / JPL figures.
Does this page integrate gravity?
No. It is an educational explorer using published figures for circular mutual orbits. It is not a gravity integrator and does not solve N-body equations.
What figures does the facts panel use?
Pluto 1188.3 km, Charon 606 km, masses 1.303e22 kg / 1.586e21 kg (~8.2:1), separation ~19,591 km, barycenter ~2,110 km from Pluto center, period 6.387 days, both tidally locked (NASA New Horizons / JPL).