杏吧原创

Hydrogen by John Rigden, Harvard University Press, $28/拢19.50/鈧�28, ISBN 0674007387 Reviewed by Graham Farmelo

NOTHING better illustrates the virtue of simplicity than the hydrogen atom. Because it has the simplest possible atomic structure 鈥� an electron orbiting a proton 鈥� hydrogen has taught us more about nature than all the other atoms. Hydrogen is also the commonest atom in the Universe and mother of all other atoms and molecules, apart from helium, which explains why John Rigden calls hydrogen the 鈥渉eroine鈥� of his book.

Rigden is deeply enamoured of physics, physicists and the historical anecdotes that bind them together. These passions are reflected in Hydrogen鈥檚 format 鈥� short essays about different aspects of the hydrogen story, focusing on its physicist-heroes (with not a woman among them).

One of the first is Johann Balmer, the Swiss high-school teacher who first spotted the simple pattern among wavelengths of the visible light emitted by hydrogen atoms. The explanation of this pattern was one of the first triumphs of early quantum theories, and soon after, the first relativistic quantum theory of the electron did even better. Later, meticulous studies of the element鈥檚 spectrum showed the need for an improved theory, which arrived in the form of quantum electrodynamics. Insights into the atomic nucleus came from the odd distribution of electrical charge in the deuteron (a proton bound to a neutron, the nucleus of the hydrogen isotope deuterium), discovered in 1939 by a group led by I. I. Rabi, Rigden鈥檚 special hero.

Now the element has given us insights into the big bang and after, by measuring how much of the Universe is made of primordial hydrogen. All this is familiar material, elegantly and accessibly retold by our unfailingly urbane guide. Rigden comes into his own, however, when he tackles less well-known topics such as the production in 1996 of anti-hydrogen, the first anti-atom, and the important role hydrogen played in the first ever preparation of a Bose-Einstein macroscopic quantum state.

Great stories, beautifully told. What a shame Rigden chose to leave out the story of the hydrogen bomb 鈥� but perhaps it would have spoiled the romantic tone.

Still, he has done physicists a service with his touching love letter to their favourite atomic quarry. What is needed now is for a similarly smitten chemist, and perhaps even a biologist, to write an affectionate epistle. This heroine deserves to be multiply wooed.