The Magic Furnace: The Search for the Origins of Atoms

  • Marcus Chown
Oxford University Press: 2001. 240 pp. $25
Fiery origins: atoms continue to be forged in the hot interiors of stars. Credit: NASA/SOHO

The Magic Furnace tells the story of the discovery of the birth of atoms inside stars. Is it a good book? When I was about halfway through, I was doubtful. But the second half, which discusses the build-up of atomic nuclei, is very good. Marcus Chown is happiest when recounting the personal stories of scientists and their achievements. The account of Gustav Kirchhoff's discovery that each element has a characteristic spectrum, and his identification of the elements in the spectrum of sunlight, makes enjoyable reading. And the book reaches its climax with the work of Fred Hoyle and Willy Fowler, who discovered that some atoms were formed in the Big Bang and others continue to be formed in stars.

The trouble with the first half of the book is that the author does not distinguish clearly enough between new and important findings and those that are well known. Thus, in discussing Arthur Eddington's work on stars, Chown writes the “gas is to generate a high pressure”; it has been known since Robert Boyle's time (1662) that gas has a pressure proportional to its density and temperature. Eddington would not have started his work on stars had he not known this.

Chown describes the carbon–nitrogen cycle and the proton–proton chain, in which hydrogen is converted to helium. But although he tells us that the carbon–nitrogen cycle is sensitive to temperature, we are not told that the temperature at the centre of a star (which can be as much as 40 million degrees kelvin) depends on the material that makes up its bulk. Only much later does the author tell us that stellar material is not like the material on Earth, but is predominantly hydrogen; this reduces the computed central temperature of the Sun from 40 to 13 million degrees kelvin.

The Magic Furnace ends with an informative account of how atoms are made in the extremely hot material in the Big Bang, and in the less hot interiors of stars. It explains why the Big Bang made only helium, and why there is about 25% (by weight) of helium in the Universe. We discover why there is an abundance of atoms up to the atomic weight of iron, but fewer of those of higher atomic weight, and how the latter are formed in stars by the addition of neutrons to existing nuclei, one by one. And finally we are told how the atoms created in stars escape into the interstellar medium to form new stars.