born in Austria. In 1948, with T. Gold and F. Hoyle, he proposed the steady-state theory of the Universe in which matter is continuously created. Although abandoned in favour of the Big Bang theory, it stimulated much important astrophysical research, particularly Hoyle’s work on nucleosynthesis. Bondi also studied relativity, showing in 1962 that the existence of gravitational waves follows from the theory of general relativity.