In DepthNuclear Physics

An earthly search for gold's cosmic origins

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Science  24 Nov 2017:
Vol. 358, Issue 6366, pp. 981-982
DOI: 10.1126/science.358.6366.981

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Last month, astronomers wowed the world when they announced that they had seen two neutron stars merge, apparently creating heavy elements such as gold and platinum and spewing them into space. Nuclear physicists at Michigan State University in East Lansing also cheered the find, as they are building an atom smasher, the $730 million Facility for Rare Isotope Beams (FRIB), that could decipher exactly how those elements were forged in the inferno. The elements presumably emerge from the so-called rapid neutron process, or r-process, in which a nucleus gains weight by gobbling up one neutron after another. At the same time, a nucleus can change its chemical identity through radioactive β decay, which turns neutrons into protons and bumps the nucleus up the periodic table of elements. Exactly how a nucleus evolves depends on the speed of the decay and the probability that it will soak up another neutron. Those parameters are poorly known. FRIB aims to change that by making as many of the neutron-laden nuclei as possible and measuring their masses and lifetimes. First proposed in 1999, the project didn't get the greenlight for construction from the Department of Energy until 2014. Now, however, the project is ahead of schedule and on budget, and it should be up and running by 2021—if federal budget politics do not slow it down.