Biking the Solar System

To finish up a several month long exploration of astronomy, I decided to do a walk/visual model of the solar system. The concept is simple but elegant: using familiar objects as stand-ins for the planets to show relative size and then walking the relative distances between the planets gives a better idea of the amazing size of the solar system than trying to imagine it in your head.

I got the instructions here.

First, gather the objects you will need. The sun is a ball about 8 inches in diameter. The smallest planets are heads of a pin, Earth and Venus are cloves (they suggested a peppercorn which we didn’t have), others are various nuts or acorns. The website suggests using familiar objects rather than worrying as much about exactness of size or shape. The idea is that the difference between a peanut and a pinhead is remembered better than between two balls of clay or a similar model.

I attached ours to index cards to ensure that they could be seen and also so that we could easier find them when we were done with our walk.  And yes, we included Pluto. We know it’s not really a planet but we’re retro when it comes to planets.

Next you head out to where you want to start the walk. You start by putting your “sun” down on the ground and then pacing out the distance to Mercury, putting down the Mercury card and repeating for each planet. The distances to pace are in the instructions I linked to above. The amazement starts to happen when you get to the distance between Mars and Jupiter, which is a much larger distance than between the previous planets. By the time you reach Pluto you will have walked over half a mile. The sun is no longer visible. It’s even more amazing walking back along your path and seeing how long it takes to reach Neptune from Pluto and then how once you reach Mars the inner four planets seem very close together.


It helped that we had a long, straight and relatively flat place to do this. I’m pretty sure in the end that David didn’t really understand this except that now he thinks the planets are peanuts. At four, I figure it’s enough that he knows there are such things as planets. John got the idea though and it was also a good review for him. As we put each planet down we talked a little bit about things he remembered learning about that planet.

And Ruth? She thinks any excuse to get out of the house is a good one.

3 thoughts on “Biking the Solar System

  1. Pingback: Astronomy Adventures | Supratentorial

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