Seeing the Unseen

Freeman Dyson reviews The Fly in the Cathedral: How a Group of Cambridge Scientists Won the International Race to Split the Atom by Brian Cathcart, and A Sense of the Mysterious: Science and the Human Spirit by Alan Lightman, in the New York Review of Books:

Every atom is almost entirely made of empty space, with a tiny object called the nucleus and even tinier objects called electrons flying around inside it. Ernest Rutherford, a young New Zealander working in Manchester, England, discovered this fact about atoms in 1909. He shot fast particles at a thin film of gold and observed the way the particles bounced back. The pattern of the recoiling particles showed directly the internal structure of the atoms in the film. The discovery of the tiny nucleus came as a big surprise to Rutherford as well as to everybody else. The phrase “the fly in the cathedral” described what Rutherford discovered. The fly is the nucleus; the cathedral is the atom. Rutherford’s experiment showed that almost all the mass and almost all the energy of the atom was in the nucleus, although the nucleus occupied less than a trillionth part of the volume.

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