Atomic and Hydrogen Bombs

The binding energy of protons and neutrons in the atomic nucleus is a million times larger than the binding energy of electrons in an atom. Therefore, the explosive yield of a weapon based on nuclear reactions is a million times larger than the yield of one based on chemical reactions. This was realized immediately after fission was discovered in Germany, just as World War II was brewing, and this led different governments to create Research & Development projects aimed at eventually building the first “atomic bomb.” The largest obstacle to overcome was to accumulate a “critical mass” of the fissionable isotopes 235U or 239Pu. The United States secured enough of both to explode the first fission device at a test in New Mexico, in July 1945, after the war with Germany was over. In August, 1945, the US destroyed the Japanese cities of Hiroshima and Nagasaki with bombs based on 235U and 239Pu, respectively, with the aim of forcing Japan to end the war. The Soviet Union developed their own weapon a few years later. Nuclear fusion-based weapons, known as “hydrogen bombs,” were developed in the 1950s by both nations, with a thousand times higher explosive yield than the first fission weapons. Battlefield weapons with “enhanced radiation warheads” were developed in the 1960s.