Rayleigh

Rayleigh is a surname of English origin and a name associated with several scientific ideas named after John William Strutt, 3rd Baron Rayleigh (1842–1919), an English physicist. Strutt made foundational contributions to optics and to the study of gases; he shared the Nobel Prize in Chemistry in 1904 for work on the discovery of noble gases, notably argon, with William Ramsay.

Rayleigh scattering refers to the elastic scattering of light by particles much smaller than the wavelength of light. It explains why the sky appears blue during the day and reddens at sunrise and sunset, and it depends inversely on the fourth power of wavelength.

The Rayleigh criterion is a criterion for the resolvability of two close point sources in an optical system, introduced by Rayleigh. It states that two sources are just resolvable when the principal diffraction maximum of one image coincides with the first minimum of the other. In practice, angular resolution is about 1.22 times the wavelength divided by the aperture diameter (1.22 λ/D).

In statistics and wireless communications, the Rayleigh distribution models the magnitude of a two-dimensional Gaussian random vector. It is used to describe envelope fading in non-line-of-sight wireless channels (Rayleigh fading), where signal amplitude follows a Rayleigh distribution.

In seismology, Rayleigh waves are surface seismic waves named after Lord Rayleigh. They propagate along the Earth’s surface and produce ground movement with elliptical particle motion, often contributing to strong, long-duration shaking during earthquakes.

Rayleigh is also the name of a town in Essex, England.