Albert Einstein warns President Roosevelt that uranium nuclear chain reactions could produce vast energy and powerful bombs, and recommends the U.S. government maintain contact with physicists working on this research and secure uranium supplies, noting Germany has already halted uranium exports from Czechoslovakia.
A 2018 physics paper argues that the Fermi paradox—the puzzle of why we observe no intelligent alien life despite mathematical models suggesting it should be common—dissolves when accounting for realistic uncertainties in parameters like the Drake equation. The authors show that when uncertainty distributions are properly modeled rather than assumed certain, there is substantial probability of no other intelligent life in the observable universe, eliminating the paradox.