For more than 40 years, a subatomic mystery has puzzled scientists: Why do the fragments of splitting atomic nuclei emerge spinning from the wreckage? The resulting shards come out spinning, which can prove especially bewildering when the nuclei that split were not spinning themselves. They focused on the gamma rays released after nuclear fission, which encoded information on the spin of the resulting fragments. Specifically, they could help shed light on the nature of the gamma rays emitted by spinning nuclear fragments during fission, which can heat reactor cores and surrounding materials. In such cases, Wilson says, the incoming energy might potentially lead to pre-scission influences on the spinning of the resulting fragments.