1. The problem statement, all variables and given/known data The spontaneous fission rate for U-238 is roughly 1 fission per gram per 100 seconds. Show that this rate is the equivalent to a half-life for spontaneous fission of ~5.5x1015 years 2. Relevant equations none that I can find in my book 3. The attempt at a solution I'm thinking this is just basically a conversion of units problem, but want to check that with someone else. Not entirely sure where I would start so any help would be appreciated.