Sir Martin Ryle

Sir Martin Ryle
(1918 - 1984)

British radio astronomer who developed revolutionary radio telescope systems and used them for accurate location of weak radio sources. With improved equipment, he observed the most distant known galaxies of the universe. Ryle and Antony Hewish shared the Nobel Prize for Physics in 1974, the first Nobel prize awarded in recognition of astronomical research.
Ryle was the nephew of the philosopher Gilbert Ryle. After earning a degree in physics at the University of Oxford in 1939, he worked with the Telecommunications Research Establishment on the design of radar equipment during World War II. After the war he received a fellowship at the Cavendish Laboratory of the University of Cambridge, where he became an early investigator of extraterrestrial radio sources and developed advanced radio telescopes using the principles of radar. While serving as university lecturer in physics at Cambridge from 1948 to 1959, he became director of the Mullard Radio Astronomy Observatory (1957), and he became professor of radio astronomy in 1959. He was elected a fellow of the Royal Society in 1952, was knighted in 1966, and succeeded Sir Richard Woolley as Astronomer Royal (1972-82).

Ryle's early work centred on studies of radio waves from the Sun, sunspots, and a few nearby stars. He guided the Cambridge radio astronomy group in the production of radio source catalogues. The Third Cambridge Catalogue (1959) helped lead to the discovery of the first quasi-stellar object (quasar).

To map such distant radio sources as quasars, Ryle developed a technique called aperture synthesis. By using two radio telescopes and changing the distance between them, he obtained data that, upon computer analysis, provided tremendously increased resolving power. In the mid-1960s Ryle put into operation two telescopes on rails that at the maximum distance of 1.6 km (1 mile) provided results comparable to a single telescope 1.6 km in diameter. This telescope system was used to locate the first pulsar, which had been discovered in 1967 by Hewish and Jocelyn Bell of the Cambridge group.