Thursday, 22 September 2005

E=mc2: A biography of the world’s most famous equation – David Bodanis *****

David Bodanis is a storyteller, and he fulfils this role with flair in E=mc2. The premise of the book is simple – Einstein himself has been biographed (biographised?) to death, but no one has picked out this most famous of equations, dusted it down and told us what it means, where it comes from and what it has delivered. Allegedly, Bodanis was inspired to write the book after hearing see an interview with actress Cameron Diaz in which she commented that she’d really like to know what that famous collection of letters was all about.
Although the book had been around for a while already when this review was written (September 2005), it seemed a very apt moment to cover it, as the equation is, as I write, exactly 100 years old. So when better to have a biography?
Bodanis starts off by telling us about the individual elements of the equation. What the different letters mean, where the equal sign comes from and so on. This is entertaining, though he seems to tire of the approach on the final straight, brushing aside the origins of the 2 for “squared” with the comment that it went through about as many permutations as “=”, without bothering to tells us what, where and when. But after this, the book settles down to a more people-driven history approach, first over the derivation of square laws, then taking us through Einstein’s formative period, then moving on to the first realization of the potential power of nuclear fission, to its wartime deployment and the role of E=mc2 in the heart of the sun.
What this book does exquisitely is find the details of history, the personal, individual quirky details, the make things so much more interesting. There’s been much written about the Manhattan Project and the development of the atomic bomb, but much less, for instance, about the raid on a Norwegian heavy water factory that was instrumental in slowing down the development of a German nuclear weapon during the Second World War. Similarly, Bodanis delights in finding historical characters, often women, who have been significant in science but rarely get the exposure of their more famous counterparts – for instance Lise Meitner and Cecilia Payne.
There is one concern here. Bodanis is so focussed on making the story easy to digest and flow effortlessly, that he can be a little cavalier with the facts, or over-simplify the science. When describing the evolution of the “squared” part of the equation, he is at his worst. He makes confusing statements, in one paragraph saying “If a five pound ball is going at 10 mph, it has 50 units of energy. Then in the next paragraph “If a five pound ball is going at 10 mph, it has 5 times 102, or 500 units of energy. While he goes on to describe the experimental proof of the latter, he slips from saying the energy “is mv2″ to a more accurate “is proportional to mv2″, without explaining this shift. He the effectively says that it’s c2 in E=mc2 because it’s similar in some hand-waving way, without explaining why.
The occasionally sketchy approach to the science is certainly a weakness, but it is more than adequately countered by the excellent historical storytelling, giving a freshness to what would otherwise be an over-told story. Well worth looking out. Happy birthday E=mc2
Review by Brian Clegg

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