AG14: How Many Cabs In The Universe?

Download Episode 14

In this episode Chris and Russ explore 'Fermi problems', the kind of problems that scientist Enrico Fermi used to pose to his students. A Fermi problem is a question that involves estimating quantities that seem completely out of reach, but aren't. Usually the rule is that you work out a Fermi problem just with your general knowledge and your wits.

Some sample Fermi problems are: How many dogs live in your city? How much does your local grocery store or 7-11 gross in a day? How many hot dogs do Americans eat in a year? How thick is a piece of paper? In fact, making up the questions is almost as much fun as solving them.

A good biography of Enrico Fermi, the originator of the Fermi problem is Enrico Fermi, Physicist You can find a collection of Fermi questions or problems
here.

According to wikipedia number of cabs in New York is actually 13,087: God knows where Russ got the 18,000 number but close enough for a Fermi problem!

The SETI Institute has a good explanation of the Drake equation. You can also find a video of Carl Sagan explaining it on youtube.