Planet Walk: a solar system you can walk
If the Sun were a basketball, Earth would be a peppercorn 25.8 m (85 ft) away, and Neptune a blueberry 778 m (2553 ft) away. Shrink the Sun to a ball you can hold, and the planets shrink with it: most become specks you could lose in your hand, and the gaps between them become a long walk. Pick your Sun, then walk out to Neptune one planet at a time.
Solar system scale model measurements
Every size and distance below is NASA's, from its planetary fact sheets (checked 2026-10-29), shrunk by the same amount. Distances are each planet's average distance from the Sun.
If the Sun is a basketball (24 cm)
| Planet | Size | From the Sun |
|---|---|---|
| Mercury | 0.84 mm (a grain of sand) | 10.0 m (33 ft) |
| Venus | 2.1 mm (a peppercorn) | 18.6 m (61 ft) |
| Earth | 2.2 mm (a peppercorn) | 25.8 m (85 ft) |
| Mars | 1.2 mm (a grain of salt or a poppy seed) | 39.3 m (129 ft) |
| Jupiter | 25 mm (a grape) | 134 m (440 ft) |
| Saturn | 21 mm (a grape) | 247 m (810 ft) |
| Uranus | 8.8 mm (a blueberry) | 494 m (1621 ft) |
| Neptune | 8.5 mm (a blueberry) | 778 m (2553 ft) |
If the Sun is a softball (9.7 cm)
| Planet | Size | From the Sun |
|---|---|---|
| Mercury | 0.34 mm (a grain of sand) | 4.0 m (13 ft) |
| Venus | 0.84 mm (a grain of sand) | 7.5 m (25 ft) |
| Earth | 0.89 mm (a grain of sand) | 10.4 m (34 ft) |
| Mars | 0.47 mm (a grain of sand) | 15.9 m (52 ft) |
| Jupiter | 10.0 mm (a blueberry) | 54.2 m (178 ft) |
| Saturn | 8.4 mm (a blueberry) | 99.7 m (327 ft) |
| Uranus | 3.6 mm (a peppercorn) | 200 m (655 ft) |
| Neptune | 3.4 mm (a peppercorn) | 314 m (1032 ft) |
If the Sun is a ping-pong ball (4 cm)
| Planet | Size | From the Sun |
|---|---|---|
| Mercury | 0.14 mm (a speck of dust) | 1.7 m (5 ft) |
| Venus | 0.35 mm (a grain of sand) | 3.1 m (10 ft) |
| Earth | 0.37 mm (a grain of sand) | 4.3 m (14 ft) |
| Mars | 0.20 mm (a speck of dust) | 6.5 m (21 ft) |
| Jupiter | 4.1 mm (a pea) | 22.4 m (73 ft) |
| Saturn | 3.5 mm (a peppercorn) | 41.1 m (135 ft) |
| Uranus | 1.5 mm (a grain of salt or a poppy seed) | 82.3 m (270 ft) |
| Neptune | 1.4 mm (a grain of salt or a poppy seed) | 130 m (425 ft) |
How to do a planet walk
- Pick your Sun and print the signs. Choose a place long enough: a schoolyard for a ping-pong ball, a park for a softball, a long street or a big park for a basketball.
- Put the Sun at the start. Walk the big steps on each sign and stand that planet there; a big step is about a meter.
- Look back from each planet. From Neptune, the Sun is a dot. That emptiness is what the solar system is mostly made of.
Why a scale model surprises everyone
Pictures of the solar system squash the planets together so they fit on a page, and draw them far too big. At one true scale, the four rocky planets huddle near the Sun, then there is a long walk to Jupiter, and each giant after it is roughly twice as far again. Pluto, a dwarf planet, would be past Neptune. Read about every world at three levels on the Space page, or put them in order with the planets in order strip.
“If the Sun were a basketball, you could hide Earth behind a peppercorn. Space is mostly space.”