A scale you can walk
The solar system at 1:10 billion: Neptune would be 450 m from the Sun
If the Sun were 14 cm wide, Earth would be a 1.3 mm bead 15 m away. Choose a town and see how far the other worlds would sit.
Where does the model begin?
Search and map drawing run on your device using a bundled GeoNames list. Your search text and chosen locality coordinates never leave your device.
The scale map
Distances from the Sun
Rings show mean orbits (semi-major axes) at 1:10 billion, with an imagined Sun at the selected point. The background shows GeoNames settlements only: no streets or walking routes. Voyager’s ring shows its Earth-centred range only, not its direction. Search and map work offline after the page loads.
Small at first, vast at the edge
How far would you walk for each planet?
At this scale, the Sun is nearly 14 cm wide. To keep one consistent convention, planetary diameters use the NSSDC equatorial values, while distances are semi-major axes calculated by JPL Horizons.
Earth is about a 1.3 mm bead. The diameter uses NASA’s published equatorial convention; a mean-diameter convention gives a different value.
A moving landmark
Voyager 1 is heading for one light-day from Earth
Calculating NASA’s estimate…
NASA estimates when Voyager 1 will be one light-day from Earth. The countdown uses that published date, while the map’s current position starts from a dated JPL Horizons ephemeris point and advances using the observed geocentric range rate. That rate includes Earth’s motion; it is not the spacecraft’s cruise speed.
At this scale, one light-day is about 3 km from your selected point. Proxima Centauri, the nearest star after the Sun, would be about 4,017 km away — too far for this local map.
Walk at your own pace
Step counter
Set an average step length, then add the steps you take. The counter compares your walk with Earth’s scaled distance; it does not use GPS or record your steps.
0 m to Earth’s orbit.
For any walk: use pavements, not roads; children should walk with an adult.
Class worksheet
The model uses a 1:10 billion scale. The Sun is 14 cm wide, Earth is 15 m away, Jupiter 78 m, and Neptune 450 m.
- Draw a 14 cm circle for the Sun.
- Mark Earth, Jupiter and Neptune along one line.
- At a 70 cm step, how many steps reach Earth’s orbit?
- Why can’t Voyager 1 and Proxima Centauri fit on the same sheet?
Write one observation: ________________________________________________
Safety: walk on pavements and go with an adult.
Method and sources
Every number has a clear source trail
This distance model is a geometric comparison, not a map of the planets’ positions on a particular day. Orbits are ellipses; the semi-major axis gives the mean distance used here.
- NASA NSSDC · Planetary Fact SheetEquatorial planetary diameters, the convention used for planet sizes.
- NASA NSSDC · Sun Fact SheetThe Sun’s volumetric mean radius; its diameter is twice the radius.
- JPL HorizonsOrbital semi-major axes and daily geocentric ephemeris for Voyager 1.
- NASA · Voyager 1 and Voyager 2 nowPublished estimate for the one-light-day milestone.
- ESA Gaia Archive · Gaia DR3Gaia DR3 parallax for Proxima Centauri; distance is recalculated from parallax.
- GeoNamesRomanian localities; bundled locally under the CC BY 4.0 licence.