By Peter Weiss
About a half-billion years ago, the early Paleozoic seas were filled with now-extinct creatures called trilobites, which had flat, oval, segmented shells. Recently, a team of theoretical physicists saw the trilobite’s shape in the electron cloud they’ve plotted for a hypothetical two-atom rubidium molecule.
The image leaped out at Hossein R. Sadeghpour of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and his colleagues when they modeled a molecule that may form in Bose-Einstein condensates, which are minuscule clouds of ultracold atoms (SN: 7/15/95, p. 36). Says Sadeghpour, “We joked that the experiment was done several hundred million years ago, and we had just stumbled upon [the result].”