Energy equals mass times the speed of light squared

Earlier this month I got around to reading E=mc²: A Biography of the World’s Most Famous Equation by David Bodanis, which I borrowed from Adam ages ago and can finally return. It’s supposed to be sort of a layman’s book, and I enjoyed it for what that’s worth, but I found myself wishing it had gotten even deeper into the science. I suppose the book did its job, since it made me want to read more about the topic. By the way, at the end there’s an appendix which follows up on all the people mentioned in the book, and I came across the following bit, which I found kind of touching:

Using material from [Ernest] Lawrence’s lab, Emilio Segrè had become the first person to create the element technetium … At the reduced salary Lawrence gave him, there had been no chance of bribing any consular officers to get his elderly parents out of Italy. His mother was captured during a Nazi manhunt in October 1943, and murdered soon after that; his father, who had been safely hidden in a papal palace, died of natural causes the next year.

When the war was over Segrè went to his father’s tomb, scattering a small sample of technetium from Lawrence’s lab over it: “The radioactivity was miniscule, but its half-life of hundreds of thousands of years will last longer than any other monument I could offer.”

Aside: An episode of PBS’ NOVA called “Einstein’s Big Idea” will air on Tuesday, Oct. 11; the companion website is pretty comprehensive.