Sir Fred Hoyle (June 24, 1915 – August 20, 2001) was a British astronomer, notable for a number of his theories that run counter to current astronomical opinion, and a writer of science fiction, including a number of books co-authored by his son Geoffrey Hoyle .

An early paper of his made an interesting use of the Anthropic Principle. In trying to work out the routes of stellar nucleosynthesis, he observed that one particular nuclear reaction, the Triple-alpha process, which generated carbon, would require the carbon nucleus to have a very specific energy for it to work. The large amount of carbon in the universe, which makes it possible for life to exist, demonstrated that this nuclear reaction must work. Based on this notion, he made a prediction of the energy levels in the carbon nucleus that was later borne out by experiment.

While having no argument with the discovery of the expansion of the universe by Edwin Hubble, he disagreed on its interpretation: Hoyle (with Thomas Gold and Hermann Bondi, who he had worked with on radar in World War II) argued for the universe being in a "steady state", with the continuous creation of new matter driving the expansion of the universe, rather than the universe beginning and expanding explosively in a "Big Bang". Ironically, he is responsible for actually coining the term "Big Bang" in one of his papers criticising the theory. Continuous creation offered no explanation for the appearance of new matter, but in itself was no more inexplicable than the appearance of the entire universe from nothing; in the end the discovery of the cosmic microwave background radiation led to the nearly unanimous acceptance by astronomers (Hoyle being one exception) of the Big Bang theory.

He did a series of radio talks on astronomy for the BBC in the 1950s; these were collected in the book The Nature of the Universe, and he went on to write a number of other popular science books. He wrote some science fiction; most interesting is The Black Cloud in which it transpires that most intelligent life in the universe takes the form of interstellar gas clouds, who are surprised that intelligent life can form on planets, and a television series A for Andromeda. In 1957 he was elected a Fellow of the Royal Society, and he was knighted in 1972.

In 1968, he won the Gold Medal of the Royal Astronomical Society. In 1970 he won the Bruce Medal. In 1971 he won the Henry Norris Russell Lectureship. In 1977, he received the Klumpke-Roberts Award of the Astronomical Society of the Pacific. Together with Edwin Salpeter, he was awarded the 1997 Crafoord Prize from the Royal Swedish Academy of Sciences.

In his later years, with Chandra Wickramasinghe , he promoted the theory that life evolved in space, spreading through the universe via panspermia, and that evolution on earth is driven by a steady influx of viruses arriving via comets.

Further occasions on which Hoyle aroused controversy included his questioning the authenticity of fossil archaeopteryx and his condemnation of the failure to include Jocelyn Burnell in the Nobel Prize award recognising the discovery of pulsars.

Fiction

• The Black Cloud, 1957
• Ossian's Ride, 1959
• A for Andromeda, 1962
• Fifth Planet, 1963 (co-authored with Geoffrey Hoyle )
• Andromeda Breakthrough, 1965 (co-authored with John Elliott)
• October the First Is Too Late, 1966
• Seven Steps to the Sun, 1970 (co-authored with Geoffrey Hoyle)
• The Inferno, 1973 (co-authored with Geoffrey Hoyle)
• The Molecule Men and the Monster of Loch Ness, 1973 (co-authored with Geoffrey Hoyle)
• Into Deepest Space, 1974 (co-authored with Geoffrey Hoyle)
• The Incandescent Ones, 1977 (co-authored with Geoffrey Hoyle)
• The Westminster Disaster, 1978 (co-authored with Geoffrey Hoyle)
• Comet Halley, 1985