Martin Ryle

[b. Brighton, England, September 27, 1918, d. Cambridge, England, October 14, 1984]

Radio astronomy was still a brand new science in 1946 when Ryle began surveying the radio universe. By 1959 he had prepared a catalog of some 500 radio sources, which he expanded to about 5000 sources by 1965. He was a pioneer in using two radio telescopes and interferometry to improve resolution. From 1972 through 1974 he was also England's Astronomer Royal.

British radio astronomer Sir Martin Ryle (1918 - 1984) developed revolutionary radio telescope systems and used them to locate weak radio sources. With his equipment, he revealed the most distant known galaxies of the universe. In 1974, he shared the Nobel Prize for physics with Antony Hewish, the first time astronomers received the award. Specifically, Ryle was recognized for developing "aperture synthesis," a technique that employs computer technology as a solution to some of the fundamental problems involved in the construction of radio telescopes. Ryle was able to make several important discoveries, including the nature of radio stars and the origins of radio scintillation.

Ryle was born September 27, 1918, in Brighton, Sussex in England to John A. and Miriam (Scully) Ryle. Martin Ryle was the second of five children. His family name was respected throughout England, as his father was a physician. After World War I, John Ryle was appointed to the first chair of social medicine at Oxford University in England. He also was the director of Oxford's Institute of Social Medicine.

Ryle's uncle, Gilbert Ryle (1900 - 1976), was an influential philosopher. As a professor of metaphysical philosophy at Oxford, he had an enormous influence on the development of twentieth century analytic philosophy. He authored The Concept of the Mind (1949) and Ryle's Dilemmas (1954).

Keeping with family tradition, Martin Ryle was educated at Bradfield College and Oxford University, where he graduated in 1939 with a degree in physics. He earned first - class honors in Oxford's school of natural sciences.

Radar Research During World War II

World War II had just started when Ryle graduated from Oxford. So, instead of going on to graduate studies, he was assigned to work in the British government's Telecommunications Research Establishment (later renamed the Royal Radar Establishment), where he became involved in research into the new science of radar. He worked briefly at the Cavendish Laboratory at the University of Cambridge before taking on the wartime assignment. He worked on the design of radar equipment and radio systems that Great Britain's Royal Air Force used. His primary assignment was developing counter measures for enemy radar.

There, Ryle first worked with Hewish. Ryle worked with the Telecommunications Research Establishment until 1945. He later admitted that during this period, he gained significant engineering experience but soon forgot most of what he had learned about physics.

Returned to Cambridge After War

After his wartime research, Ryle, like many of his colleagues, was convinced that radar was applicable to observational astronomy. He would become one of the important early investigators of extraterrestrial radio sources, and would develop advanced radio telescopes using radar principles.

After the war, in 1945, Ryle returned to Cavendish Laboratory at Cambridge. J. A. Ratcliffe, a scientist who had led the ionospheric work at Cavendish before the war, encouraged him to apply for a fellowship. Ratcliffe wanted Ryle to join his group and investigate radio emissions from the sun, which had recently been discovered by accident through radar equipment.

Later, Ryle recalled, in the autobiography he wrote when he received his Nobel Prize: "During these early months, and for many years afterwards both Ratcliffe and Sir Lawrence Bragg, then a Cavendish professor, gave enormous support and encouragement to me. Bragg's own work on X - ray crystallography involved techniques very similar to those we were developing for 'aperture synthesis,' and he always showed a delighted interest in the way our work progressed."

Ryle received the fellowship and studied radio astronomy at Cavendish. His fellowship would run through 1948.

Radio Astronomy Emerged

Radio astronomy, or the study of objects in space by observing the radio waves they emit, was a new field at the time. But it would soon open up many parts of the universe that had been invisible to scientists and researchers. For centuries, astronomers knew only about objects in space that shone with visible light.

Matter in space emits radiation from across the electromagnetic spectrum, or the range of wavelengths produced by the interaction of electricity and magnetism. Along with light waves, the electromagnetic spectrum includes radio waves, infrared radiation, ultraviolet radiation, X - rays, and gamma rays.

The development of radio astronomy was due largely to American radio engineer Karl Guthe Jansky. In 1932, Jansky developed the first, simple radio antenna that picked up short radio waves that came from distant parts of the universe. Jansky knew such waves could provide information about astronomical bodies in much the same way as light waves. His discoveries gained credibility among many astronomers as research continued.

The next advancement came in 1937, when amateur astronomer Grote Reber built a 31 - foot - diameter radio dish in his backyard. The field advanced even more with the wartime research at the Telecommunications Research Establishment. Later, Ryle would greatly improve the power of radio telescopes.

Catalogued the Heavens

Ryle's early work centered on studies of radio waves from the sun, sunspots, and nearby stars. Starting in the late 1940s, Ryle led his colleagues on the Cambridge radio astronomy research team in the production of surveys of radio - emitting sources in the heavens. These surveys were essentially maps of the sources. He completed the first cosmological survey in 1950, identifying 50 sources. In his second survey, in 1955, Ryle found almost 2,000. The third survey led to the discovery of the first quasi - stellar object, or quasar. Specifically, Ryle and his colleagues had located a radio source in the constellation Cygnus, which was 500 million light years away from the earth. The ability to detect an object at such a distance had significant implications. It meant radio telescopes could see very far back into the history of the universe. Therefore, radio telescopes could help reveal information about the creation of the universe (the science of cosmology).

To map such distant radio sources as quasars, Ryle developed a technique called aperture synthesis, or interferometry. Basically, aperture synthesis involves two radio telescopes. By changing the distance between them, Ryle obtained information that, when analyzed by a computer, provided tremendously increased resolving power.

The resolving power of any telescope, or its ability to separate two nearby objects in the sky, depends on the wavelength of the radiation detected. As the wavelength of radio waves is much longer than that of light waves, a radio telescope must be considerably larger than a light telescope with similar levels of resolving power. Ryle realized the size of the telescope he would need to do his work must be hundreds or thousands of meters in diameter. In other words, the telescope would have to be enormous.

Ryle developed a solution that on the surface seemed simple yet effective. He designed several moveable telescope parts. The technique was called aperture synthesis. Basically, the technique involves a number of small telescopes with positions that are mutually adjustable within nearly five kilometers, or about three miles. This enabled Ryle to achieve a precision similar to what an enormous telescope would have produced. For his research in developing the technique, Ryle received the Nobel Prize in 1974.

"The wealth of detail in the charting of the universe carried out in recent years with this apparatus is absolutely unique," the Nobel committee wrote in 1974. "For a number of years, Ryle has been making observations with his various instruments that have been of crucial significance in the study of the physical characteristics of stars and stellar systems and for cosmology, the study of the development of the universe as a whole."

When Ryle developed the first radio interferometer, which involves multiple radio telescopes linked electronically, he used twelve telescopes. The radio waves each telescope detected were sent to a single receiver and a computer processed the information. The result was the creation of picture much more detailed than anything a single radio telescope could have produced. During the next ten years, astronomers from around the world would copy the technique.

That Ryle had to work on the rather primitive computers available at the time made his accomplishment even more extraordinary. To compensate, he developed a "phase - switching" receiver that cleaned up the radio signal, eliminating unwanted noise and interference. Using this device, Ryle was able to discover 50 new astronomical sources of radio waves.

In 1967, Ryle worked with Hewish and graduate student Jocelyn Susan Bell Burnell. Using a form of the radio interferometer, they discovered pulsars, which are rapidly spinning neutron stars that produce a blinking on - and - off signal.

Distinguished Career

Ryle received prestigious appointments and distinctions. He was knighted in Great Britain in 1966 for his achievements in radio astronomy. While serving as university lecturer in physics at Cambridge from 1948 to 1959, he was elected to a fellowship at Trinity College. Also, he became director of the Mullard Radio Astronomy Observatory in 1957. In addition, in 1959, he became the first Cambridge professor of radio astronomy.

He retired from Cambridge in 1982. During his tenure, he received a number of honors and awards, including the Hughes Medal of the Royal Society in 1954, the Gold Medal of the Royal Astronomical Society in 1964, the Henry Draper Medal of the United States National Academy of Sciences in 1965, and the Royal Medal of the Royal Society in 1973.

Ryle was married in 1947 to Ella Rowena Palmer, a nurse and physiotherapist. They had two daughters, Alison and Claire, and one son, John.

After a long battle with lung cancer, Ryle died on October 14, 1984, in Cambridge, England.

During his last decade, he was greatly interested in renewable energy and nuclear disarmament. He took special interest in the possible role of renewable energy in the world's future, and was a strong advocate for wind power development in Great Britain. In 1981, he published Towards the Nuclear Holocaust, which expressed his concerns about the nuclear arms race and the misuse of science.

Books

Notable Scientists: From 1900 to Present, Gale Group, 2001.

World of Scientific Discovery, Gale Group, 1999.

Online

"Martin Ryle - Authobiography," Nobelprize.org,http://nobelprize.org/physics/laureates/1974/ryle-autobio.html (January 8, 2005).

"Press Release: The 1974 Nobel Prize in Physics," Nobelprize.org,http://nobelprize.org/physics/laureates/1974/press.html (January 8, 2005).

"Sir Martin Ryle," Britannica Guide to Nobel Prizes, http://www.britannica.com/nobel/micro/515 - 10.html (January 8, 2005).

"Sir Martin Ryle," Carthage.org,http://www.cartage.org.lb/en/themes/Biographies/MainBiographies/R/Ryle/1.html (January 8, 2005).

"The Martin Ryle Trust," sgr.org,http://www.sgr.org.uk/MRT.html (January 8, 2005).

For more information on Sir Martin Ryle, visit Britannica.com.

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