How Far is That Planet?

This experiment comes from my new "How Do You Know That?" show. How do we know how far away the planets are? Did someone take a tape measure and stretch it from the Earth to each planet? Did someone get in their car and drive there, to check the mileage? No, but we still know how far away they are.

To see how this is done, we will need:

Making a Scale Model of the Solar System

Take a moment and imagine our solar system. Think about what it would look like if you were moving through it in a space ship. Once you have that image in your mind, get ready to replace it with a much more accurate image.

Our solar system is a very large place, and most of it us empty space. Because of the way it is shown in textbook drawings, on TV, and in movies, most people have trouble imagining the actual sizes and distances of the planets. This simple activity lets you use a scale model to visualize those sizes and distances.