## Can You Fit the Entire Universe into a Nutshell?

An old math joke tells you how to catch a tiger: Build a cage in the interior of a perimeter and perform* inversion*.

Not only does Maxwell's constant $b^2=1/\epsilon_0\mu_0$ not coincide with the velocity of light, but different definitions of the speed of light turn out to be inverses of one another.

One definition used in the Kennedy-Thorndike (KT) interferometer uses a metric

$$c^2dt^2(1-\beta^2)=ds^2\pm2v\cos\omega dt,$$