When “magic” stops working
For decades, physicists have relied on a set of special numbers—2, 8, 20, 28, 50, 82, 126—known as “magic numbers” to make sense of the atomic nucleus. These numbers mark especially stable arrangements of protons and neutrons, where the tiny particles lock into neat, spherical shells. A new experiment has now found a patch of the nuclear world where this rulebook breaks down, revealing a kind of “forbidden zone” on the nuclear map where magic numbers collapse and nuclei dramatically change their shape. Inside the crowded nuclear city Every atom has a dense core, the nucleus, where protons and neutrons jostle in an unimaginably tight space. Rather than flying around at random, they occupy layered “shells” of energy, somewhat like floors in a high‑rise building. When a floor is completely full—at one of the magic numbers—the building is unusually stable: the nucleus tends to stay compact and spherical, and it takes extra effort to shake it up....