Manhattan Project: Arrival of the first plutonium sample at Los Alamos. A new way to detonate the bomb is designed: a subcritical mass (not capable of triggering a reaction) is taken and surrounded with traditional explosives. The explosion compresses the plutonium mass, which, due to its density, triggers a chain reaction. The compression occurs so rapidly that fission doesn’t have time to defuse. The input will be free neutrons in the air. The bomb is theoretically ready.
