The Right Coast

August 06, 2004
The Equation
By Maimon Schwarzschild

Interesting book by David Bodanis on "The World's Most Famous Equation: E = mc2". Everyone knows the equation, of course. But when you stop to think about it, the eqaution is terrifically counter-intuitive. It would seem to be apples and oranges, for one thing. Mass is weight, and energy is the sort of thing measured in volts, whereas "c" is the speed of light, and speed is in a different category, isn't it?

Then there is the equation's enormous disproportion. Mass can be transformed into energy, but the energy you get is mass multiplied not just by the astronomically large speed of light, but by the speed of light squared: an astronomical number multiplied by that astronomical number!

And then, if mass can be transmuted into energy, why should the energy you get be a neat multiple of some (apparently unrelated) cosmic number like the speed of light? Why not an immensely long and complicated equation that no one but a physicist could possibly remember?

Bodanis' book is mostly a series of biographical sketches of the scientists (Einstein and others) who discovered E = mc2 and put it to use. But Bodanis also goes some distance to answering questions like those I posed above; and to do it in simple, non-scientific and non-mathematical language.

But if you are curious, as I am, for more of the actual reasoning behind Einstein's equation, Bodanis promises in the book to post more on the web at He has not actually done so, it turns out. It would have been an interesting publishing idea: new media reinforcing old... Oh well.