The fine-structure constant is defined in terms of the speed of light
**c**, Planck's constant **h**, and the charge
of the electron **e**. I usually write it as

There is an interesting story about the fine-structure constant. Early on, someone had a theory that it was exactly 1/136. When the measurement got better, he produced an improved theory that it was exactly 1/137. His theory didn't make much sense to people, but it took a much better measurement the second time to disprove him!

It's interesting that **g**
is close to two (it's about 2.001159652188) for an
important reason, while
is close to 1/137 for no apparent reason at all.

- Elastic Theory has Zero Radius of Convergence.
- What is the radius of convergence?
- Famous Asymptotic Series

Last modified: May 24, 1997

James P. Sethna, sethna@lassp.cornell.edu

Statistical Mechanics: Entropy, Order Parameters, and Complexity, now available at Oxford University Press (USA, Europe).