The solar system is difficult to show correctly. Why? It is difficult because the size of things are vastly different. Let me use units common in solar-system astronomy, the Astronomical Unit (or AU). One AU is the distance from the Sun to the Earth. If I want to look at all the planets, I would need to go out to about 30 AU (to Neptune – remember that Pluto is not a planet). That is not a problem but then if I want to look at the size of even the Sun, it is just 0.001 AU across. And the Earth is even smaller, at 0.0001 AU. So that is the problem. The distance from the Sun to Neptune is like 5 orders of magnitude greater than the scale of Earth. You can’t really show that on paper.
Normally, what textbooks do is to show two separate scales. One scale showing the orbits of the planets and another scale showing the size of the planets. Unfortunately, this way you don’t get a good sense of how far apart these things are. One way is to show the model of the solar system in one web page – as shown here. Another way is to build a scale model in the real world.
Real world solar system models can be found in lots of places, the one that inspired us was the Maine solar system model. We originally tried to make something similar to this, but it was logistically very difficult (property issues and everything). Eventually we (by we I mean some people in our university) decided to make one that went just around our campus. For our scale, the sun is about 1 meter across and 1 AU is about 100 meters.
For each planet, there is a circular poster the size of the Sun (in 2-d). On this circle, there is another circle representing the size of that particular planet. On the side, there are some informational-type posters with more info. These are designed to be “temporary” and are made with some type of plastic printed stuff glued on some type of foam backing (clearly, I had very little to do with that part). In fact, this project was a collaboration between our department (Chemistry and Physics) and the Department of Visual Arts. The stands and posters were designed by students (Stacy Kest, Shalayne Heffner, Brett Blanchard, and Daniel Ippolito).
Here is a map showing the location of the planets.
And here is a sample poster.
Finally, as a way of documenting the scale, I walked around campus with a video camera. Here is the movie that I made (time-compressed to prevent too much boredom). Unfortunately, some parts get a little shaky – enough that it might make you barf. Please don’t blame me. I would make another one, but it just won’t stop raining here.