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The Peppercorn Model of the Solar System

The Peppercorn Model, also known as the Thousand Yard Model, is a scale model of the solar system which shows the relative sizes of the planets and the distances between them at the same time using the same linear scale.
At this scale the Sun is about the size of a soccer ball, the Earth is about the size of a peppercorn, and Pluto is a grain of salt about 1000 yards from the Sun.
As you walk among the planets you will not just see but also feel the vast emptiness of space even in our own solar system.
Solar System
Model Object
and Diameter
Distance (in AU) Added
Object inches mm AU yards meters yards meters
Sun a soccer ball 8.7'' 22 cm 0.00     0 yd 0 m
Mercury a pin head 0.030'' 0.8 mm 0.39 +10 yd +9 m 10 yd 9 m
Venus a peppercorn 0.075'' 1.9 mm 0.72 +9 yd +8 m 19 yd 17 m
Earth a peppercorn 0.079'' 2.0 mm 1.00 +7 yd +7 m 26 yd 24 m
Mars a pin head 0.042'' 1.1 mm 1.52 +14 yd +12 m 39 yd 36 m
*Ceres a grain of salt 0.006'' 0.15 mm 2.77 +32 yd +29 m 72 yd 65 m
Jupiter a walnut,
or chestnut
0.89'' 23 mm 5.20 +63 yd +57 m 134 yd 123 m
Saturn an acorn
or hazelnut
0.75'' 19 mm 9.58 +113 yd +103 m 247 yd 226 m
Uranus a coffee bean 0.318'' 8 mm 19.2 +249 yd +228 m 497 yd 454 m
Neptune a coffee bean 0.308'' 8 mm 30.1 +281 yd +257 m 777 yd 711 m
*Pluto a grain of salt 0.015'' 0.38 mm 34.8 ↑ +121 yd +111 m 899 yd 822 m
*Quaoar a grain of salt 0.007'' 0.17 mm 43.7 +230 yd +210 m 1128 yd 1032 m
*Haumea a grain of salt 0.010'' 0.25 mm 50.0 ↓ +163 yd +149 m 1291 yd 1181 m
*Makemake a grain of salt 0.009'' 0.23 mm 52.5 ↑ +65 yd +60 m 1356 yd 1240 m
*Eris a grain of salt 0.014'' 0.37 mm 95.5 ↓ +1109 yd +1014 m 2466 yd 2255 m
*dwarf planets
Model Object
Distance (in AU)
semi-major axis

Scale: 1 inch = 100,000 miles   --   On this scale the next nearest star, Proxima Centauri, would be about 4,000 miles away!

1 AU = 1 Astronomical Unit = average (mean) distance between the Earth and the Sun
1 AU = 1.4960 × 1011 meters =  9.2956 × 107 miles

  The orbits of the planets are elipses. The distances reported for the major planets are the semi-major axis of the orbit. The distances for the dwarf planets are the actual distance from the Sun at some recent time and will be updated occasionally. The arrows ↑ and ↓ indicate whether the object's distance from the sun is currently increasing or decreasing.


It is possible to set up or walk the model almost anywhere that you can walk for a thousand yards (or meters). It does not have to be in a straight line, since the goal is to show you the sizes of the planets compared to the sizes of the orbits. If you do set it up in a straight line (as on a long bridge or trail) you should remind everyone that the planets never line up all in one line.

That said, here are some locations where the model has been set up with success, including maps to show where the planet stations can be placed.


The Peppercorn Model of the Solar System
A presentation by Eric Myers for the joint meeting of the New York, New Jersey, and New England sections of the American Association of Physics Teachers, held at Marist College on Sept. 28th 2013.
Solar System Mystery Walk
The main idea of the Solar System Mystery Walk is that a group will travel through a scale model of the solar system marked out using the conventional symbols for the planets, which most people don't recognize. When you arrive at a new planet, whoever in the group is carrying the envelope marked with that symbol opens it up to reveal the name of the planet and share some facts about it.

Other Scale Models

The 1000 yard model or Peppercorn Model is not the only scale model of the solar system, though it does have the distinct advantage of illustrating the relative scales of the planets and their orbits using everyday objects. Models at other scales can do the same thing, though there has to be some balance: of the model is too small in distance, the planets will be too small to see; if the planets are larger then the distances may be too large to travel comfortably.

That said, here are some other scale models of the solar system that use the same scale for the sizes of the planets and the sizes of their orbits.

  1. Sagan Planet Walk in downtown Ithaca, New York
  2. Voyage Model Solar System on the Capital Mall in Washington, D.C.
  3. Other solar system models (from Wikipedia)
  4. SOLAR SYSTEM Passport to the Planets - A Scale Model of the Solar System - Student activity for 4th, 5th, and 6th grade students
  5. Scales of the Universe - relative sizes of all things large and small
  6. If the Moon were only one Pixel - a tediously accurate scale model of the solar system
  7. To Scale: The Solar System - On a dry lakebed in Nevada, a group of friends build the first scale model of the solar system with complete planetary orbits
  8. Lightspeed Model of the Solar System - an alternative model of the solar system where the planets are arranged by the time it takes light from the Sun to reach them.


  1. The Thousand-Yard Model or, the Earth as a Peppercorn by Guy Ottewell
  2. The Thousand-Yard Model or, The Earth as a Peppercorn from NOIRLab - the National Optical-Infrared Astronomy Research Laboratory (previously hosted by NOAO - the National Optical Astronomy Observaotry).
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