Obituary: Professor Raymond Lyttleton

Raymond Arthur Lyttleton, mathematician and theoretical astronomer: born 7 May 1911; Lecturer in Mathematics, Cambridge University 1937-59, Stokes Lecturer 1954-59, Reader in Theoretical Astronomy 1959-69; Experimental Officer, Ministry of Supply 1940-42; Technical Assistant to Scientific Adviser to the Army Council 1943-45; FRS 1955; Royal Medallist of Royal Society 1965; Jacob Siskind Visiting Professor, Brandeis University 1965- 66; Visiting Professor, Brown University 1967-68; Member, Institute of Astronomy, Cambridge University 1967-95; books include The Comets and Their Origin 1953, The Stability of Rotating Liquid Masses 1953, The Modern Universe 1956, Rival Theories of Cosmology 1960, Man's View of the Universe 1961, Mysteries of the Solar System 1968, The Earth and its Mountains 1982, The Gold Effect 1990; married Meave Hobden; died 16 May 1995.

Raymond Lyttleton was a leading theoretical astronomer, who was appointed in 1969 to a specially created professorship in the subject at Cambridge University, which was the base from the 1930s for almost all his work.

He was educated at King's School, Birmingham, where he was a near contemporary of Enoch Powell, and Clare College, Cambridge, where he read mathematics, taking the Tripos with distinction in 1933. He was elected a Fellow of St John's College in 1937 and appointed a lecturer in mathematics in the same year.

In the early spring of 1939 I began a collaboration with Ray Lyttleton that extended over a decade or more. It had to do with the ability of astronomical bodies to acquire additional material through gravitational attraction. Much denigrated at first by the astronomical community, the idea has been seen in recent years to be an important astronomical process, with large numbers of papers on it, now published routinely year by year. A similar history accompanied and followed the publication in 1940 of the importance of molecules, especially hydrogen molecules, as a constituent of interstellar gas.

Lyttleton had a special gift that he deployed in such controversial matters, which I always thought he inherited from his grandfather, a well-known Irish lawyer. It was to invent absurd examples of the forms of logic used by his opponents, a device which, he hoped, would have the effect of showing them that they were wrong and, more certainly, of making the rest of the world laugh uproariously. He carried on a considerable correspondence, of which it is to be hoped that that with George Bernard Shaw and that with Sir Donald Bradman will be published. The story of how the latter interchange of letters began bears repeating.

Like some, but not many, before him, Lyttleton in his teens was torn between becoming a professional cricketer and a mathematician. Mathematics was his eventual choice, but not before he had thoroughly learnt the empirical factors which govern the swing of a cricket ball.

He had done this from observing an outstanding swing bowler of pre-war years, called Root. Root could not afford to practise at the nets with new balls. According to Lyttleton, he worked on old balls with a brush and shoe polish, following which he could produce late swing as the ball fell towards the ground, either to the right or left, "just as if he had told it what to do while still in mid-air". Thus already at 16 Lyttleton knew the importance of one side of the ball's being polished, and of the use of the seam for directing it left or right. What he did not know at that stage was why.

This came many years later with wind-tunnel experiments done by an acquaintance, Professor Stevens. The experiments distinguished turbulent and laminar flows around the two halves of the ball, a condition that produces a large sideways force on it. And which, most importantly, showed the effect to be largest at medium-fast speeds, not at very fast speeds.

This was in the mid-1950s, when another acquaintance persuaded Lyttleton to give a talk on the BBC Third Programme with the title The Swing of the Cricket Ball. It happened during an Australian tour, for which Bradman was team manager, and anxious to keep his team in the hotel and not out on the tiles of a night. Lyttleton's talk seemed good for a laugh and the team was persuaded to amuse itself by listening to it. But, as Bradman wrote subsequently to Lyttleton, they spent the rest of the evening discussing what they had just heard. The point about the most effective swing not occurring at the highest speeds hit the bell with the Australian fast bowlers. A correspondence over the years followed from this first step.

Although much impeded by illness in later years, Lyttleton maintained his interest both in mathematics and in cricket. I happened to visit him at the time, two or three years ago, that the Pakistani fast bowlers were devastating the England tail with what became known as reverse swing, a time when there was confusion in the press about what was happening. "It's not what they think," Lyttleton said. "It's got nothing to do with polishing. What it needs is a rough ball, uniformly rough without pockmarks. Aerodynamically, it's like a baseball pitch. For a given bowler it goes only one way. And it doesn't have an optimum speed. It swings more and more the faster the delivery, going like the square of the speed."

Lyttleton had his own Bradman story. It had nothing to do with statistics. It occurred in the course of a Test match, but was never reported in the press or in Wisden. Yet Lyttleton always said that in his view it was Bradman's finest feat. One day that story may be told.