Sir Fred Hoyle was an English astronomer and cosmologist, primarily remembered today for his contribution to the theory of stellar nucleosynthesis, and his often controversial stance on other cosmological and scientific matters, such as his rejection of the Big Bang theory in favour of a steady state universe and the panspermia theory of the origin of life on earth. He is considered one of the most creative and provocative astrophysicists of the second half of the 20th Century.
Fred Hoyle was born during the First World War, on 24 June 1915, in the village of Gilstead, West Yorkshire, England. After his father’s cloth business failed, the family moved briefly to Rayleigh, Essex in 1921 before returning again to the Bingley area, and Hoyle moved from school to school, regularly playing truant and missing long periods of school. Despite his attempts to avoid formal education, however, he did show an interest in educating himself, especially from chemistry and astronomy books, and, when he won a scholarship to Bingley Grammar School in 1926, he started to approach education with a more positive attitude.
After a series of failed scholarship exams, he managed to obtain a scholarship to study science at Emmanuel College, Cambridge in 1933. He persevered at mathematics, always his weakest subject, and, by sheer determination, he was placed in the top ten of the 1936 Mathematical Tripos and was awarded the Mayhew Prize as the best student in applied mathematics. In other subjects, he was taught by some outstanding people during his undergraduate years at Cambridge, including Max Born (quantum mechanics), Arthur Eddington (general relativity) and Paul Dirac (who replaced Rudolph Peierls as Hoyle’s supervisor).
Hoyle’s interests turned towards mathematical problems in astronomy and, as he continued to win prizes and awards, he was elected to a Fellowship at St John's in 1939 for his work on beta decay. He married Barbara Clark in late 1939, and they went on to have a son, Geoffrey, in 1942 and a daughter, Elizabeth.
Although his career was largely put on hold with the outbreak of World War II, it was also a fertile period for gestating some ideas he would later expand on. He had refused to be drafted for weapons research, having immediately realized that the recently discovered phenomenon of a nuclear fission chain reaction could be used to create a nuclear bomb, and he mainly worked on radar for the Admiralty in Nutbourne, near Portsmouth. It was there that he met fellow astronomers Hermann Bondi and Thomas Gold, and the three were able to discuss astronomy in spare moments (they would later propose together the steady-state cosmology for which Hoyle is probably best known). Through his work on radar, he also visited the USA in 1944, where he became more familiar with the atomic bomb project. It was then that he first began to hypothesize on the role of nuclear reactions in stars.
At the end of the war, he returned to Cambridge as a Junior Lecturer in Mathematics. He published an important paper in 1945 on the structure of stars, in which he introduced a new method for solving the equations determining the structure of a star with a convective core, and discussed the most advantageous way of integrating the equations of stellar equilibrium.
In a 1946 paper, on the creation of elements and the synthesis of elements from hydrogen, Hoyle introduced (or at least formalized) the concept of nucleosynthesis in stars, building on earlier work in the 1930's by Hans Bethe. Stellar nucleosynthesis is the process of nuclear reactions taking place in stars to build the nuclei of the heavier elements, which are then incorporated in other stars and planets when that star "dies", so that the new stars formed now start off with these heavier elements, and even heavier elements can then be formed from them, and so on.
Hoyle also theorized that other rarer elements could be explained by supernovas, the giant explosions which occasionally occur throughout the universe, whose immensely high temperatures and pressures would be sufficient to create such elements. Remarkably, he had found a way of testing the theory of star formation in the laboratory, and was able to prove his earlier prediction that carbon could be made form three helium nuclei without an intervening beryllium stage. Although his co-worker William Fowler eventually won the Nobel Prize in Physics in 1983 for his contributions to this work, for some reason Hoyle’s original contribution was never recognized.
As part of this work, Hoyle invoked the so-called Anthropic Principle to make the remarkable prediction, based on the prevalence on Earth of carbon-based lifeforms, that there must be an undiscovered resonance in the carbon-12 nucleus which facilitates its synthesis within stars. He calculated the energy of this undiscovered resonance to be 7.6 million electron-volts, and when Fowler's research group eventually found this resonance, its measured energy was remarkably close to Hoyle's prediction.
It was also this work that caused Hoyle, an atheist until that time, to begin to believe in the guiding hand of a god (what would later be called “intelligent design” or “fine tuning”), when he considered the statistical improbability of the large amount of carbon in the universe, carbon which makes possible carbon-based lifeforms such as humans.
In 1948, Hoyle was promoted to Lecturer in Mathematics at Cambridge and given tenure. He published two papers on steady-state cosmology in 1948, providing the only serious alternative to the Big Bang which agreed with key observations of the day. He found the idea that the universe had a beginning to be philosophically troubling, and, along with Thomas Gold and Hermann Bondi (with whom he had worked on radar during World War II), he argued that the universe was actually in a "steady state", despite the clear evidence that the galaxies we observe are moving away from each other. His justification hinged on the creation of matter between the galaxies over time, so that, even though galaxies get further apart, new ones develop between them to fill the space they leave, so that the overall density of the universe remains more or less constant.
In 1949, Hoyle began a popular and often repeated series of BBC radio broadcasts on astronomy, with versions being broadcast in the United States as well as in a book “The Nature of the Universe”. It was in the last of these radio lectures that Hoyle coined the phrase "Big Bang" for the creation of the universe, although many people believe he actually intended it as a scornful description of a theory which he did not himself accept. In 1957, he published “The Black Cloud”, the first of many science fiction novels.
He became Plumian Professor of Astrophysics and Natural Philosophy in Cambridge in 1958, a position he held until his resignation in 1972. In 1966, he founded the renowned Institute of Theoretical Astronomy at Cambridge and was its director until 1972, the year in which he received his knighthood. He received many awards and prizes throughout the 1950s, 1960s and 1970s, and was elected to many academies and learned societies, including the Royal Society of London (1957), the American Academy of Arts and Science (1964), the National Academy of Sciences of the United States (1969) and the Royal Irish Academy (1977).
He resigned all his positions in Cambridge in 1972, frustrated by the politics, and moved to the relative solitude of the Lake District. However, he continued to publish interesting (often unconventional or controversial) theories, such as those concerning Stonehenge (which, he argued, was built for the purpose of tracking the orbits of the Sun and Moon to facilitate the prediction of solar and lunar eclipses), Darwinism (in 1978, he described Charles Darwin's theory of evolution as “wrong” and argued that natural selection could not possibly explain evolution) and paleontology (he questioned the authenticity of fossil Archaeopteryx).
In the 1980s, he developed and promoted, along with Chandra Wickramasinghe, the theory of “panspermia”. This is the idea that the origin of life on Earth must have involved cells which arrived from space, and that evolution on earth is driven by a steady influx of viruses arriving from space via comets. He calculated the chances of the simplest living cell forming out of some primordial soup as infinitesimally small, and described that theory as “evidently nonsense of a high order”.
Hoyle died on 20 August 2001, aged 86, in Bournemouth, England, after suffering a severe stroke the previous month.