Geoff Greene’s lifetime is inextricably linked to that of the neutron. His tireless pursuit of this scientific mystery—finding out how long a neutron lives and what that reveals about the weak force, the Big Bang, and other fundamentals of science—has earned him the Tom W. Bonner Prize in Nuclear Physics from the American Physical Society. Greene was recognized “for foundational work establishing the field of fundamental neutron physics in the US, for developing experimental techniques for in-beam measurements of the neutron lifetime and other experiments, and for realizing a facility for the next generation of fundamental neutron physics measurements.” He will accept the award at a ceremony in April.