In 1960 there were only 10 million people living in Australia, 45th in the world. Surprisingly, there were more radio astronomers (and associated engineers) than any other country. How was this possible? I will attempt to answer this remarkable achievement and show the impact that the Australians and British had in the decade 1945 to 1955, before the US began a massive program in radio astronomy. The Australians made numerous discoveries that changed the course of astronomy: the radio detection of the million degree solar corona, classification of the types of solar bursts, the invention of aperture synthesis (1945), the first earth rotation image (the quiet sun at 20 cm) and the identification of the first non-solar system objects with optical objects. Examples of the latter are the Crab Nebula, Virgo A and Centaurus A- NGC 5128 (in 1949). In addition, the first reliable all sky survey of a few thousand radio sources (at a wavelength of 3.5 m) by Mills and the elucidation of the spiral structure of the Milky Way using the newly discovered 21 cm hyperfine transition of HI (along with colleagues in the Netherlands). The major rivals of the Australians were the two groups in the United Kingdom at Cambridge and Manchester. The major cosmological conflicts between Ryle at Cambridge, a proponent of an evolving universe, and the steady state universe proposed by Hoyle, Bondi and Gold originated in 1954-1955; Mills in Sydney asserted that his source counts favoured a steady state universe.

The founder of the Australian group was Joe Pawsey (1908-1962). Along with Prof Ron Ekers (past President of the International Union) and Dr Claire Hooker (historian of science at the University of Sydney), we are completing a book From the Sun to the Cosmos, J.L. Pawsey, Founder of Australian Radio Astronomy– to be published in 2020 and now 2/3 complete. Pawsey is one of the “big three” of radio astronomy in the post-war era: Sir Martin Ryle of the Cavendish Laboratory Cambridge (Nobel Prize Physics 1974), Sir Bernard Lovell of Jodrell Bank, University of Manchester. These three became the first radio astronomy Fellows of the Royal Society of London (Ryle-1951, Pawsey-1954 and Lovell-1955).

I will also describe briefly three books about the history of Australian radio astronomy: two books about the first woman radio astronomer – Ruby Payne- Scott-in 2009 and 2013, and Four Pillars of Radio Astronomy: Mills, Christiansen, Wild, Bracewell in 2018. All are available via university library web sites on SPRINGERLINK for no cost. Numerous web sites about Ruby Payne-Scott are available on line.

I became fascinated with the history of Australian radio astronomy when I moved to Australia as a postdoc over 50 years ago.