Niels Bohr

July 2026

Who he was

Niels Bohr (1885–1962) was a Danish physicist, one of the principal architects of quantum mechanics. His 1913 atomic model — electrons in discrete, quantized orbits — was an early landmark bridging classical and quantum physics. He received the 1922 Nobel Prize in Physics and later led the Copenhagen school that gave the standard (“Copenhagen”) interpretation of quantum mechanics its name.

What he’s known for on this site

Alongside John Wheeler, Bohr proposed the Bohr-Wheeler fissionability parameter in 1939 as part of the original liquid-drop theory of nuclear fission — the condition under which a nucleus becomes unstable against spontaneous fission, built directly on the same terms as the semi-empirical mass formula.

Catalog status: Proven Systems

The liquid-drop fission model is standard, well-confirmed nuclear physics, directly responsible for correctly predicting which nuclei are fissile.

Mentioned on this site

• Bohr-Wheeler Fissionability Parameter
• Semi-Empirical Mass Formula — the related nuclear model it’s built from

Where this touches PBT

Paper 13 uses the Bohr-Wheeler fissionability parameter and the semi-empirical mass formula exactly as standard nuclear physics defines them, as a real baseline before introducing PBT’s own additions.