Theory

Inspired by a falling snowflake, Kepler suggests that the symmetrical shapes of crystals might be due to the symmetrical arrangement of the atoms from which they are formed. (1611)

While playing cards Mendeleyev realises that the elements can be organised into the Periodic Table based on their chemical properties. (1866)

Maxwell translates Faraday’s experimental results into mathematical language and constructs a unified theory of electromagnetism. (1873)

Building on Rutherford’s experimental results, Bohr devises the first model of the atom using an early version of quantum mechanics. (1913)

The quantum theory of electromagnetism ‘QED’ is invented by Feynman, Schwinger and Tomonaga. Dyson realised how the pieces fit together while dozing on a greyhound bus crossing America. (1948)

Landau is released from prison and immediately produces a theory of superfluidity. He follows this with a theory of superconductivity. Both theories are based on Landau’s innovative ideas about symmetry breaking. (1950)

Higgs invents a mechanism based on symmetry breaking that will enable a unified theory of the electromagnetic and weak forces to be constructed. (1964)

Following the discovery of charm, the standard model of particle physics becomes established. It consists of a periodic table of matter particles that interact via two forces described by the electroweak theory and a theory of the strong force known as QCD. (1974)

Experiment