Sir Francis Graham-Smith, radio astronomy pioneer whose work indicated that the universe had a beginning

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Sir Francis Graham-Smith, the former Astronomer Royal, who has died aged 102, was a pioneer of radio astronomy, carrying out research which helped to establish our modern picture of the universe.
In the 1950s, he was the first astronomer to measure the accurate positions of distant 'radio galaxies', those that have large regions of radio emission that extend well beyond their visible structure. Together with Sir Martin Ryle, his predecessor as Astronomer Royal, he suggested that the speed at which these galaxies are moving away from us indicated that the universe must have had a definitive beginning.
These findings helped to demolish the then fashionable steady state theory of Sir Fred Hoyle and others, which held that the universe had always existed. In the 1970s, Graham-Smith did much detective work on pulsars – fast-spinning stars made up of matter so dense that one ton can be contained in a teaspoon.
King Charles II established the office of Astronomer Royal in 1674. Appointed in 1982, Graham-Smith was the 13th to hold the office – an unlucky portent as it turned out, for the 1980s saw a series of cuts in funding for astronomical research.
The shadow hanging over British astronomy partly stemmed from a public relations disaster on the night of March 13 1986 when, shortly after midnight, the European spacecraft Giotto passed through the tail of Halley's comet, sending back data to earth. The BBC, in a late-night television show, invited several astronomers, including Graham-Smith to comment on the results, forgetting that none of their guests knew much about comets.
The show was a shambles: no one could make head or tail of the Giotto data. But the real row began later in No 10 Downing Street, where Margaret Thatcher was watching the programme. She was angry at what she saw and decided that space research was a waste of money. The next year she barred British participation in a European X-ray telescope searching for black holes and rejected plans to boost the budget of the National Space Centre, a move which prompted the resignation of its director Roy Gibson.
Caught in the cross-fire, Graham-Smith strove in as civilised a manner as possible to put the case for higher investment in British astronomical research: 'We have no shortage of excellent students,' he observed in 1986, 'but they will probably work abroad. The fact that we will go on populating the world with British astronomers is absolutely splendid, but wouldn't it be nicer to think that just a few would stay at home?'
Francis Graham-Smith was born on April 25 1923 to Claud and Cicely and educated at Epsom College and at Rossall School in Lancashire. He began studying natural sciences at Downing College, Cambridge, in 1941 but did not graduate until 1946. Like his colleague Martin Ryle, he spent most of the Second World War working at the Telecommunications Research Establishment at Malvern involved in the development of radar.
This experience led him into radio astronomy and he stayed on at Cambridge after graduating to work with Ryle at the Cavendish Laboratory on radio waves from the sun and other stars. By a fortunate coincidence, the largest sunspot for many years occurred at this time – in July 1946 – and Cambridge radio astronomy grew from observations of its very powerful emissions. Soon afterwards the pair were using the same techniques to detect radio waves coming from other parts of the sky.
Setting up a simple radio telescope in a field behind the house where they both lived, they left it for 24 hours to scan the sky as the earth rotated recording the radio signal on a paper chart recorder. When they looked at the chart the next morning, they were astonished to see the trace of not one but two powerful radio sources on the recording. The radio source appeared to be coming from the constellation Cassiopeia. A few years later, the radio source was precisely located and identified with the remains of a stellar explosion in the Milky Way.
Another target of their research was a radio signal coming from a discrete source in the constellation of Cygnus. In 1952, Graham-Smith located this radio signal known as the galaxy Cygnus A (the 'A' indicating that it is the brightest light in its constellation), sufficiently accurately for a visual search to be made for a visible counterpart.
This search turned out to be a turning point in modern astronomy. American researchers using large optical telescopes found that the radio waves were coming from a galaxy of unusual shape and with a large 'redshift' – evidence that it is moving away from earth at a speed which increases with distance. This discovery demonstrated that radio astronomy could be used for penetrating great distances outside our own galaxy. Cygnus A is the first known example of a radio galaxy.
In 1952 Graham-Smith went to America to work at the Carnegie Institute in Washington, returning to Cambridge in 1953. He published a paper with Ryle in 1957 suggesting that radio signals from orbiting satellites could be used to aid navigation.
Throughout the 1960s and 1970s Graham-Smith worked on radio astronomy at Jodrell Bank, then moved into optical astronomy as director of the Royal Greenwich Observatory, where his main task was to build the new optical telescope at La Palma in the Canary Islands.
In 1977 he was part of a team working at the British-American optical telescope in New South Wales which photographed the Vela Pulsar, the brightest pulsar in the sky in terms of radio emissions, no more than 30 miles in diameter yet weighing one and a half times as much as the sun. The star's total explosion or 'supernova' had been recorded in Sumerian inscriptions.
In 1981 Graham-Smith moved back to Manchester to become only the second director of Jodrell Bank – where he had a cameo in the series Treasure Hunt, giving Anneka Rice a piggy-back to help her reach a clue. He listed bee-keeping among his recreations in Who's Who, and looked after the hives at Jodrell Bank.
In 1982 he was appointed Astronomer Royal, and he was professor of physics at Manchester from 1987 to 1990.
After his retirement, Graham-Smith – who was known as Graham to friends and colleagues – became vice-president of the Royal Society and his attention turned increasingly to the future of our own planet. In 1994 he hosted an international population summit which concluded that zero population growth 'within the lifetime of our children' was the only way to save the earth from ecological disaster.
He was knighted in 1986 and elected a Fellow of the Royal Society in 1970. He married, in 1945, Dorothy Palmer, whom he met when they were both working on radio astronomy with Martin Ryle in Cambridge; they had a daughter and three sons.
Professor Sir Francis Graham-Smith, born April 25 1923, died June 20 2025
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