Monday, 23 February 2015

Half Life - Frank Close ****

It would be easy from the title of this book to suspect that physics professor Frank Close is writing about... well, radioactive half lives, but the subtitle tells us this is really on a more complex topic: 'The divided life of Bruno Pontecorvo, physicist or spy'. (I feel there ought to be a question mark at the end of that.)

Frank Close is a familiar name, with a string of excellent books focusing on specific topics in physics like Antimatter, The Infinity Puzzle and my particular favourite, Neutrino. This last title is particular apt, as neutrinos feature heavily in Half Life too, but this is a very different beast. In Half Life we get a scientific biography of Bruno Pontecorvo, the Italian physicist who worked on nuclear reactors during the Second World War, moved to Harwell in the UK soon after, but then, in 1950, mysteriously disappeared without trace. Five years later he appeared in the Soviet Union where he lived and worked for the rest of a long life.

What's very welcome about this book is that it gives us the chance to put Pontecorvo in his place in the annals of physics. Arguably he would have been a Nobel Prize winner if he hadn't disappeared into Russian obscurity, and he continued to do important work at Dubna, particularly around neutrino theory. But Pontecorvo's disappearance meant that a) speculation about this dominated any popular writing about him and b) his scientific work didn't really get the credit he deserved.

There are really three strands here - Pontecorvo's life, his work and the nature of his relationship with the Soviet Union - and Close covers them all in some detail in over 300 pages before you reach the notes. Apart from finding out more about Pontecorvo's work on neutrinos there is some fascinating material on his time in Fermi's lab in Italy. I hadn't realised, for instance, that Fermi and his team took out a patent on the slow neutron process that made nuclear chain reactions practical. One of the reasons that some of Pontecorvo's former colleagues gave him the cold shoulder after his defection was that his disappearance damaged their lawsuit for a large payment from the US government.

I'd still say that the Neutrino book is the best way to read up on these fascinating particles - here the scence parts tend to be a bit disjointed, because some aspects of the development involved messy overlaps and the chronology flips back and forth, and the science is fitted around the people part. But you will certainly gain some insights. There is also the key mystery that has never been solved - was Pontecorvo a Soviet spy who defected when he was in danger of being revealed, or just a naive communist who thought he was heading for a better life?

Close isn't able to provide us with a definitive answer to that question, but he pieces together evidence that gives a strong suggestion of Pontecorvo's role, which Close admits was totally different to his own expectation. (You'll have to read the book to get the answer.) The detective work is painstaking, perhaps giving us rather more detail than we really want. But the story of the key few days when the Pontecorvos (his wife and children disappeared with him) gave every appearance of being on an enjoyable European motoring holiday before things suddenly become strange is told very well.

This was a part of the history of physics that has never been properly explored in popular science, with a good mix of biography and the key science behind it. While I can't go as far as one of the quotes on the back which refers to it as a 'gripping scientific spy mystery' - the grip is mostly quite loose - it is essential reading for anyone who wants to get a good feel for what Fermi's team did before the war, the machinations of wartime science spying and the development of neutrino theory. Close does a great job of putting Pontecorvo in his proper place in the history of physics, and (as much as is possible) draws back the curtain of mystery that has always covered his relationship with the Soviet Union.

Review by Brian Clegg

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