Leiden in History

Publishes mechanical ideas about gravity and centrifugal force in cosmological context.

Develops an electrodynamic theory in which charged microscopic particles account for electrical and optical behaviour in matter.

Lorentz develops electron theory and uses contraction ideas in attempts to account for electromagnetic experiments

Lorentz introduces local time in electromagnetic theory, a step toward the later Lorentz transformations

Finds that magnetic fields split spectral lines, providing evidence for charged particles participating in atomic radiation.

Lorentz publishes transformations that preserve the form of Maxwells equations for moving systems

Droste independently derives the exterior solution for a spherical gravitational field in general relativity

De Sitter develops an expanding relativistic cosmological solution without matter, influencing later debate over cosmic expansion

De Sitter finds a relativistic cosmological solution that later becomes important in expanding universe models

Develops a relativistic cosmological model with repulsive expansion-like behaviour.

With Samuel Goudsmit, proposes that the electron possesses an intrinsic angular momentum called spin.