Two independent experiments on the isotope copper-79 confirm that its nuclear neighbor nickel-78 is indeed a doubly magic nucleus.
Nuclear physicists could easily pass for magicians. They often talk about magic nuclei as if they were about to pull these objects out of a hat and show their fuzzy long ears. This funny qualifier was coined by Eugene Wigner, who believed nuclei behave like uniform liquid droplets, but had to admit the experimental evidence pointed out by Maria Goeppert-Mayer that nuclei with neutron (NN) or proton (ZZ) numbers 2, 8, 20, 28, 50, 82, and 126 were more stable than their neighbors. Goeppert-Mayer and other physicists went on to explain this phenomenon on the basis of the nuclear shell model, in which protons and neutrons fill a nucleus in energy shells, or orbitals, akin to the layers of an onion. Magic numbers correspond to the greatest gaps in energy between shells, giving extra stability to nuclei in which those shells are filled completely. When both the number of protons and of neutrons fulfills this requirement, the nucleus is called doubly magic. Read more.