Powers of Ten
Introduction:
It’s sometimes hard to imagine how big the universe is compared to the objects around us that we
understand. The following activity will help you to do so.
Activity:
Go to http://htwins.net/scale2/. If you don’t have flash, go to http://www.powersof10.com/film
and watch the video. Play around with the slider until you understand what it is depicting before
answering the reflection questions below.
Reflection:
1) Zoom out to the Milky Way galaxy and record the exponent (the x in 10x) that is shown.
The Milky Way is on the order of 1021 meters.
2) Now zoom in until you are focused on objects whose size is on the order of the negative of the
exponent you found for the Milky Way galaxy (i.e. if the Milky Way is 10x, zoom in on objects
that are at 10-x). Make a list below of what you see there (or, if nothing is there, a list of the things
nearby). Do a little research and describe the things you find. All of this means that the galaxy is
as many times bigger than you as you are than the things on the list!
At 10-21 m, we find quarks, which are particles so small that they make up the tiny particles that
make up atoms. We are
3) How many times bigger than the Milky Way galaxy is the entire universe?
The universe is at 1027 meters, which is 106 times bigger than the Milky Way.
4) How many times bigger than a single white blood cell are you?
A white blood cell is on the order of 10-5 m, which is 105 (or 10,000) times smaller than a human.
5) Which of (3) and (4) displays the biggest difference?
This means that for humans to have the same ratio of size (universe:galaxy = human:white blood
cell), humans would have to be 10 times larger than they currently are.