Abstract
The Four Pillars who feature in this book are Bernard Mills (1920–2011), William Norman (Chris) Christiansen (1913–2007), Paul Wild (1923–2008), and Ronald Bracewell (1921–2007). This remarkably talented quartet of radio astronomers established Australia as a world leader in instrumentation and discovery during the second half of the twentieth century.
The birth of radio astronomy in Australia started in the closing stages of World War II, when a large group of radio scientists who had been engaged in secret research at the Radiophysics Laboratory on the campus of the University of Sydney were given a peacetime role of carrying out pure research. From this concentration of talent, Joseph Pawsey (1908–1962) quickly arose as the founder of its radio astronomy group. An early triumph, in 1969, was the identifications of the Crab Nebula, M87, and NGC5128 with three radio “stars,” for which accurate radio positions had been obtained. This pivotal discovery established that strong radio sources were possibly associated with nebulae rather than stars.
The development of receiver instrumentation and interferometers became both exciting and urgent for further identification to succeed. At this stage the Australians were in competition with Martin Ryle’s group at the Cavendish Laboratory and Bernard Lovell’s group at Jodrell Bank. The focus of this book is on the four early-career scientists whom Pawsey attracted into his radio astronomy group at about the time it became clear that cosmic radio noise was a new phenomenon in physics that required investigation. Mills worked on the cross-type interferometers that now bear his name. Once Cygnus A was identified with a remote disturbed galaxy (1954), radio astronomers everywhere knew they were in the cosmology game. Mills and Ryle had a falling out over the reliability of radio source surveys for cosmological work; this was only resolved when Ryle in effect withdrew his second survey, which Mills had criticised, and replaced it with the definitive Third Cambridge Catalogue. The dispute between Mills and Ryle established radio astronomy as an indispensable tool for observational cosmology, which 10 years later (1964) led to the discovery of the cosmic microwave background radiation. Christiansen developed earth-rotation synthesis interferometry to produce the first image of the radio Sun. He went on to use synthesis techniques, the Fleurs Synthesis Telescope (another cross-type set up), to produce remarkable contour maps of southern radio galaxies in the 1970s.
Wild spent his entire career in Australia, as a towering figure in solar observation, and moreover a great leader at the highest level. As chairman of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), he was responsible for restructuring all areas of scientific research supported by the Australian government. His fruitful direction resulted in the construction of the Parkes radio telescope, a fully steerable 64-m dish that received live television images from the Apollo 11 Moon landing on 20 July 1969.
Bracewell shared an office at CSIRO with Christiansen and contributed mathematical expertise to early radio astronomy in Australia. In 1955 he moved to Stanford, where he established a radio astronomy institute dedicated to daily observation of the Sun. His work on the reconstruction of two-dimensional from one-dimensional images found many applications in the late 1960s.
The history of astronomy is well served by this vivid, informal account of four key players from the early days. It is written throughout with a light touch, and much warmth for the people portrayed. Many new photographs from family collections and institutional archives enliven this fast-paced narrative. There are no equations or scary Fourier transforms. The back matter includes a helpful time-line of key events, an explanation of what a radio telescope is and how it works, as well as a hilarious account of the Beer Disaster of November 1957. At that time licenced pubs were required to close at 6 pm, just 1 hour after their workplace let the beery blokes off the hook. Famously, this resulted in dense throngs of desperate drinkers elbowing their way to and from the express service bars. To find out what happened next to Wild, I refer you to Appendix B!
Four Pillars is not a scholarly history, but it is a very attractive blend of oral histories and personal recollections. It is a particularly welcome contribution because the history of astronomy in Australia tended to be neglected by professional historians, possibly because of the “tyranny of distance,” which meant that before the 1970s Australian academics were isolated from their colleagues in Europe and North America. Bottom line: this is an essential item for collections in the history of astronomy.