Einstein Should Be Grateful He Didn't Have Email

I'm reading an interesting new book, Bursts by Albert-Laszlo Barabasi. It's just released today, but I scored an advance copy by virtue of sharing the same publisher. The basic idea is simple: human behavior obeys power laws! That is, things we occasionally do tend to be clustered together, rather than simply occurring with uniform probability. I can't vouch for either the truth or usefulness of the claims put forward in the book; we all know that power laws can be slippery things. But the stories related along the way are pretty amusing. (And there's a very spiffy web page.) I'll admit that I jumped right to a chapter in the middle that relates the correspondence between Einstein and Theodor Kaluza in the year 1919 and thereabouts. Kaluza had just come up with the idea that electromagnetism could be unified with gravity by hypothesizing an extra dimension of space -- a ...