Professor Thomas Gold

Thomas Gold, astronomer: born Vienna 22 May 1920; Fellow, Trinity College, Cambridge 1947-51; staff, Cavendish Laboratory 1946-47, 1949-52; staff, Medical Research Council Zoological Laboratory, Cambridge 1947-49; Senior Principal Scientific Officer, Royal Greenwich Observatory 1952-56; Professor of Astronomy, Harvard University 1957-58, Robert Wheeler Willson Professor of Applied Astronomy 1958-59; Director, Center for Radio-Physics and Space Research, Cornell University 1959-81, John L. Wetherill Professor of Astronomy 1971-86 (Emeritus); FRS 1964; married 1947 Merle Tuberg (three daughters; marriage dissolved), 1972 Carvel Beyer (one daughter); died Ithaca, New York 22 June 2004.

Thomas Gold was a most unusual scientist. Brilliant in his ideas, unconstrained in the range of his interests, rock solid in his use of the fundamental laws of physics to make the most surprising deductions from them, making himself at home in fields of science he had had no connections with before, he was variously seen as a genius (even if a trifle rash) or as an irritating, useless interloper.

Yet he was not aiming to become a scientist, let alone an astronomer when young. Like most boys, he was interested in aeroplanes and fast cars, but that was all. Since I had a lot to do with his turning to science, I will figure rather more in this article than is customary.

He and I met on the first evening (12 May 1940) of our internment as "enemy aliens" during the Second World War. This happened because we were still classified as Austrian citizens although we lived in Cambridge. He was born in Vienna and had his secondary schooling at Zuoz College in Switzerland. In 1940 he was a first year undergraduate in Engineering at Trinity. I, also, was at Trinity, in the third year in Mathematics. We became close friends. I was much impressed by his ability in practical matters, often based on his non-mathematical, but sound understanding of the theorems of physics. We internees included future eminent scientists like Max Perutz; so there was much interesting conversation, despite the dreary background.

By the autumn of 1941 we were back in Cambridge, talking round the clock, but Tommy Gold's engineering course failed to excite him. In spring 1942, I joined the Royal Navy's radar research establishment, soon working closely with Fred Hoyle. This brilliant and stimulating man, four years my senior, was most useful at our radar tasks, since he combined deep physical insight with a sound practical sense.

I soon saw that Gold would also be useful. Hoyle immediately accepted my recommendation, despite our brief acquaintance. He had to fight the case, since Gold had finished his course indifferently. But as soon as he arrived, Hoyle saw in him a kindred spirit and found him even more useful than I had suggested. All day we talked radar, all evening we talked astronomy, since this was Hoyle's main scientific interest. So Tommy Gold and I were made astronomers!

Our small section in the establishment included several people who became outstanding scientists, such as Jerry Pumphrey, a zoologist interested in the electrical networks of the nerves. Back in Cambridge after the war ended, Gold soon focused on the sense of hearing. This sudden jump in his area of interest was stimulated by Pumphrey and was characteristic of his whole scientific life. Applying some of the radio and electrical circuit knowledge gained in his wartime work, he concluded that only electrical circuits could explain the frequency discrimination of our sense of hearing.

This was a remarkable piece of scientific work, including experimental results that were otherwise hard to explain. It led to his election to a research Fellowship at Trinity, but the existing medical research groups on hearing were not impressed. I surmise that the approach was too strange to them at the time. Forty years later, they adopted Gold's ideas.

During our wartime evening discussions, the problems of the structure and evolution of the entire universe intrigued us, as they intrigued scientists everywhere. In Great Britain, in particular, several were so impressed by apparent contradictions between the findings of the astronomy of the most distant regions (notably by Edwin Hubble) and our "local" physics that they put forward highly unorthodox hypotheses (Paul Dirac, Arthur Eddington, Edward Milne).

Looking at these papers, we were bothered by the ease with which, in a changing universe, one could assume arbitrary secular changes in our physics which had been established, cosmically speaking, at one instant of time. So we concluded that only if the universe is in a steady state could one apply confidently to the universe the scientific knowledge we had acquired in our mere instant of time. How could the universe be in a steady state although the red shifts of the distant galaxies indicated that it was expanding rapidly?

We were brought to a complete stop by this apparent contradiction, until Gold had the idea that there could be a process of "universal continual creation of matter" at a rate far too low to have been discovered by terrestrial experiments, but sufficient to keep the mean density of matter in the universe constant, balancing the outflow due to the recession of the galaxies. Minor differences in the formulation of this theory led to Gold and me writing one paper, Hoyle another.

Both papers were presented at a meeting of the Royal Astronomical Society in Edinburgh in autumn 1948. As these ideas were not difficult to understand, but striking in content, the three of us became famous overnight. In the astronomical community, a minority were much impressed, the majority sceptical.

Gold and I continued to work together for some years, producing joint papers on a variety of topics in dynamics and magnetism. In 1952, he left Cambridge for the Royal Greenwich Observatory and, a few years later, for the United States. Except for one year at Harvard, he settled at Cornell University, at first, from 1959, as the Director of the Center for Radio-Physics and Space Research, then as John L. Wetherill Professor of Astronomy from 1971 until 1986, when he became Professor Emeritus.

His interests were wide and he made major contributions to several subjects. In astronomy, his model of pulsars was universally accepted after initial hostility; his idea of accounting for the darkness of the Moon by a layer of dust became fully accepted only after a stormy rejection of his upper limit for the thickness of the dust layer.

But the most important of his interventions was in geology, where he disagreed with the otherwise universally accepted idea that oil and gas were of biological origin. He regarded them as leftovers from the original formation of the Earth. This important alternative to the orthodox view will be argued over for many years.

Tommy Gold was elected to the Royal Society in 1964 and a few years later to the US National Academy of Sciences.

Hermann Bondi