Atoms in a gas can seem like partiers at a nanoscopic rave, with particles zipping around, pairing up, and flying off again in seemingly random fashion. And yet physicists have come up with formulas that predict this behavior, even when the atoms are extremely close together and can tug and pull on each other in complicated ways. The environment within the nucleus of a single atom seems similar, with protons and neutrons also dancing about. But because the nucleus is such a compact space, scientists have struggled to pin down…