Somewhere off the chart of known nuclides lies the last redoubt of nuclear existence: the long-sought island of stability. There, but for the stabilizing effect of filled shells of nucleons, a nucleus would be torn apart by the electrostatic force between protons.
Nuclear physicists want to reach the island to test their ideas of nuclear structure and stability. The island’s size and shape—even whether it’s really an island—are all uncertain. Nuclear chemists are also keen on gaining landfall. To characterize the chemistry of the periodic table’s ultimate members, they need isotopes stable enough to study.
The island’s rough position is known. Consensus has the last neutron shell filling up at 184 neutrons, but there’s less agreement about the protons. Early theoretical calculations put the last filled shell at 114; more recent ones suggest 120, even 126.
Making a superheavy nucleus of sufficient neutrons is perhaps the biggest barrier to landing...
