September 27: Martin Ryle

Martin Ryle

September 27, 1918 - October 14, 1984

Sir Martin Ryle was an English radio astronomer who developed revolutionary radio telescope systems (e.g. aperture synthesis) and used them for accurate location and imaging of weak radio sources. In 1946 Ryle and Vonberg were the first people to publish interferometric astronomical measurements at radio wavelengths, although it is claimed that Joseph Pawsey from the University of Sydney had actually made interferometric measurements earlier in the same year. With improved equipment, Ryle observed the most distant known galaxies in the universe at that time. He was the first Professor of Radio Astronomy at the University of Cambridge, and founding director of the Mullard Radio Astronomy Observatory. He was Astronomer Royal from 1972 to 1982.

Ryle and Antony Hewish shared the Nobel Prize for Physics in 1974, the first Nobel prize awarded in recognition of astronomical research.

The focus of early work in Cambridge was on radio waves from the Sun. Ryle's interest quickly shifted to other areas, however, and to explore those he decided early on that the Cambridge group should develop new observing techniques. As a result, Ryle was the driving force in the creation and improvement of astronomical interferometry and aperture synthesis, which have contributed immensely to upgrading the quality of radio astronomical data. In 1946 he built the first multi-element astronomical radio interferometer.

He guided the Cambridge radio astronomy group in the production of several important radio source catalogues. For example, the Third Cambridge Catalogue of Radio Sources (3C) 1959 helped lead to the discovery of the first quasi-stellar object (quasar).

While serving as university lecturer in physics at Cambridge from 1948 to 1959, Ryle became director of the Mullard Radio Astronomy Observatory 1957, and 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).

Martin Ryle was undoubtedly one of the great astronomers of the 20th Century. He was sometimes considered difficult to work with - in fact he often worked in an office at the Mullard Radio Astronomy Observatory to avoid disturbances from other members of the Cavendish Laboratory and to avoid getting into heated arguments, as Ryle had a hot temper. Ryle worried that Cambridge would lose its standing in the radio astronomy community as other radio astronomy groups had much better funding, so he encouraged a certain amount of secrecy about his aperture synthesis methods in order to keep an advantage for the Cambridge group.

Ryle received the Hughes Medal (1954), the Gold Medal of the Royal Astronomical Society (1964), the Henry Draper Medal (1965), the Royal Medal (1973), the Bruce Medal (1974), and the Nobel Prize in Physics (1974). The Ryle Telescope at Mullard Radio Astronomy Observatory is named in his honor.