A Googol of Atoms? A Directed, Interrupted Case in Estimation and Large Numbers

by Stephen J. Shawl Department of Physics and Astronomy University of Kansas

You may remember a time when you were a child and you had a talk with a parent, relative, or teacher that blew your mind.  I’d like to tell you of one such talk with my daughter, Jessica, when she was a precocious 7 year old.

Jessica had just become aware of the word googol.  She was told that a googol was a very large number—a 1 followed by 100 zeros:

10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

I asked if a googol is larger than the number of atoms in the visible universe.  She said, “There must be more atoms in the visible universe than that!  How can you possibly figure it out?”  I replied, “We can figure it out together.  What do you think we might need to know, Jessica?”

How could you help Jessica?  What do you need to know?

Questions

Use scratch paper to write out responses to the following.

1. First let’s think about a number of questions:
   
   1. What do we mean by “the universe”?
   2. What is “matter”?  In what way(s) can we say how matter is present in something?
   3. Can we see all matter?
   4. What do we mean by the “visible universe”?
2. List the specific types of information you think might be needed to determine the number of atoms in the visible universe.
3. What assumptions will you be making in obtaining your final result?  How valid are those assumptions?

Date Posted:  07/14/03 nas

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