Sizing the Solar System

By Alexa (age 9, @KNEstemGirls)

Do you think the planets are distributed evenly in our solar system? Until a week ago, I thought that was true, but then I did a fun, easy exercise that you can do too.

All you need is about 100 centimeters of paper (you can use about 4 regular letter-sized pieces of paper end to end), writing tools (markers, pencils, crayons), and measuring tape.

For scale, you are going to use 1 centimeter for each AU. An AU is an astronomical unit, the distance from Earth to the Sun which is 92.96 million miles. So in our diagram, the Earth will be at 1 cm.

Place a dot at:

  • 0 centimeters and label it Our Sun.
  • 0.4 centimeters for Mercury.
  • 0.7 centimeters for Venus.
  • 1 centimeter for Earth.
  • 1.5 centimeters for Mars.
  • 2.5 centimeters and several more for the Asteroid Belt.
  • 5 centimeters for Jupiter.
  • 9.5 centimeters for Saturn.
  • 19 centimeters for Uranus.
  • 30 centimeters for Neptune.
  • 40 centimeters for Pluto.
  • 45 centimeters for Makemake.
  • You can also mark the area between 30 and 50 centimeters for the Kuiper Belt.
  • 60 centimeters for Eris, one of the “scattered disk” objects that lie between 50 and 100 centimeters on our chart

The next thing to add would be the Oort Cloud. However, the beginning of the Oort Cloud would be at 100 meters in our solar system. That is more than a football field away! And finally, the outer edge of the Oort Cloud is 1,000 meters away! This is what it looks like:


Doing this exercise, I learned that the solar system is HUGE. I also figured out that planets aren’t evenly spaced apart and the Earth is tiny compared to some other things in our solar system. What I found the most interesting was that we humans have only traveled 1/389 of an AU, which is the distance between the earth and the moon. 1/389 of an AU is so small that you could not even draw it on your diagram!

I think that you should do this exercise too. You can learn a lot from doing it and it is really fun.

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