Science: The Heart of the Atom

It seemed that the atom—already split, measured, analyzed, and prodded by great machines—had few secrets left. Scientists were almost agreed that the atomic nucleus (one-trillionth the size of an atom) is a solid sphere. Now Stanford University Physicist Robert Hofstadter and his assistants have examined the nucleus and found more space in the atom’s heart than anyone had guessed.

The Stanford scientists made their find with the most powerful “microscope” known to science. Its “eyepiece” is a 2½-ton magnet, its light source a giant accelerator that spews electrons in a thin stream. Fired at sheets of metal foil, the electrons whip through the metallic nuclei where they are shoved and twisted by faint electrical fields. In the huge eyepiece, the scattered electrons are counted, their new paths traced. All their measurements told the Hofstadter team that though the center of the nucleus is 130 trillion times denser than water, its edge thins down to cottony fluff.

New nuclear theories must be developed to explain Hofstadter’s discoveries. But he looks forward to probing still deeper into the atom. He is building a 25-ton magnet for a new eyepiece and plans a still bigger one. He and his assistants are experimenting with the university’s new accelerator that should soon be splitting electrons at the highest speed ever reached: 186,000 miles a second, only a fraction slower than the speed of light. With his new microscope, which will put the atomic nucleus in even sharper focus, Hofstadter may well probe to the innermost limits of matter.