Future physicists could potentially detect residual radiation from ancient atomic bomb detonations due to long-lived radioactive isotopes produced during fission. The ability to identify this radiation depends on various factors, including the bomb's size and type, as different bombs yield different isotopes. Environmental factors such as erosion, subduction, and biological activity can also influence the spread and detectability of these isotopes over time. While some evidence may remain detectable for thousands of years, other instances may not leave a trace. Overall, the persistence of radioactive signatures is complex and varies based on specific conditions.