The stability of nuclei decreases greatly with the increase in atomic number after curium, element 96, so that all isotopes with an atomic number above 101 decay radioactively with a half-life under a day. No elements with atomic numbers above 82 (after lead) have stable isotopes. Nevertheless, because of reasons not very well understood yet, there is a slight increased nuclear stability around atomic numbers 110 – 114, which leads to the appearance of what is known in nuclear physics as the " island of stability ". This concept, proposed by University of California professor Glenn Seaborg, explains why superheavy elements last longer than predicted.