Sir Martin Ryle
1918–1984, Brighton, England, UK, Cambridge, England, UK
English radio astronomer who invented aperture synthesis and mapped the radio sky, founding observational cosmology with radio source counts.
A wartime radar engineer, Ryle joined the Cavendish after 1945 and built a sequence of interferometers culminating in the One Mile and 5 km telescopes. His 3C and 4C catalogues of radio sources, and the source-count statistics that showed the universe evolves — contradicting steady-state cosmology — established Cambridge as the world center of radio astronomy. He was the first Astronomer Royal chosen for radio work.
Nobel-winning work
Ryle's 1974 Nobel Prize — the first ever given for astrophysics — recognized his invention of aperture synthesis and his pioneering radio sky surveys. By moving a small number of antennas so that Earth's rotation fills in a virtual dish, his interferometers achieved the resolution of an instrument kilometers wide.
The resulting catalogues (2C, 3C, 4C) located thousands of radio galaxies and quasars, and the 'P(D)' source-count analysis demonstrated that distant, early-epoch sources are more numerous than nearby ones — direct evidence for an evolving universe and against the steady-state theory.
Workplaces: Cavendish Laboratory, University of Cambridge
United Kingdom