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space is big [try it]


Astronomical numbers are difficult for human minds to grasp. And one of concepts I have had the most difficulty in conveying is that space is big. It is really really big. Even the solar system, which is quite minuscule compared to, say, the size of the Milky Way, is mindbogglingly big. And empty. There is really no way to appreciate it until you personally try to scale it down to numbers in our immediate experience.

Try this: make a scale model of the solar system, starting with a regular sized object to represent the Sun, and start placing planets at proportionally correct distances, using objects that are proportionally the right size. For example, if the Sun is a big beachball a foot in radius, the Earth would be a little peanut about half a cm thick placed 219 feet away. Where would you put the Moon? Jupiter? Pluto? How far away would alpha Centauri be?

If you wanted to fit the entire solar system inside your school grounds, how big would the Sun have to be?

In a sense, spatial scaling is relatively easy. How would you go about scaling time? Or mass?

The Boston Museum of Science has an installation called the Community Solar System that is such a scale model.

Here’s a nice video that describes just how far the Moon is from the Earth: