The Nuclear Age
Splitting the atom, and what followed.
The nuclear age began with the discovery of nuclear fission in 1938 by Otto Hahn and Fritz Strassmann, explained theoretically by Lise Meitner and Otto Frisch. Within seven years it had produced both a weapon and a power source.
Fission and fusion
| Fission | Fusion | |
|---|---|---|
| Process | Heavy nucleus splits | Light nuclei combine |
| Fuel | Uranium-235, plutonium-239 | Hydrogen isotopes |
| Conditions | Achievable now | Requires extreme temperature and pressure |
| Waste | Long-lived radioactive products | Far less, shorter-lived |
| Status | Powers reactors and early weapons | Powers stars; net-gain power not yet sustained |
The Manhattan Project
The US programme employed over 100,000 people across sites at Los Alamos, Oak Ridge and Hanford. The first test, Trinity, was on 16 July 1945. Bombs were dropped on Hiroshima on 6 August and Nagasaki on 9 August 1945, killing well over a hundred thousand people, mostly civilians, with deaths from radiation continuing for years.
Many of the scientists involved spent the rest of their lives arguing about the decision, and their disagreement is part of the historical record rather than a footnote to it.
The arms race
The Soviet Union tested in 1949, and the standoff that followed rested on mutually assured destruction — both sides retaining enough second-strike capacity that attacking guaranteed their own destruction. Stockpiles peaked at over 60,000 warheads in the 1980s and have fallen substantially since, though nine states hold weapons today.
Civilian power
Nuclear power generates electricity with very low carbon emissions and a strong safety record per unit generated. It also produces waste requiring isolation for millennia, and the accidents at Three Mile Island, Chernobyl and Fukushima shaped public opinion durably. The debate turns on how those risks weigh against climate ones.