John Paul Wild - World Lead in Solar Research

World Lead in Solar Research

Wild's team then built and from 1967 operated a three-kilometre diameter radio-heliograph at Culgoora, near Narrabri in northern New South Wales. It was to become a ground-breaking instrument producing real-time images of solar activity across a range of altitudes from the Sun's surface. In the late 1960s and early 1970s the team led the world in solar research, attracting prominent solar physicists from around the world.

Until then, all results from the solar radio-spectrographs had been inferred from studying the Sun by looking at its spectrum with only very limited angular resolution. Wild wanted to

actually see what these phenomena looked like on the Sun, actually get a moving picture of them. The frequency range that we were interested in was around about the metre wavelengths. To get the resolution roughly equivalent to that of the human eye at these long wavelengths required an aperture some three kilometres in diameter. So I devised a method of synthesising a three kilometre aperture with 96 antennas in a ring.

With Pawsey's help, £630,000 was raised from the Ford Foundation to build the Culgoora radio-heliograph. The heliograph stayed in operation for 17 years from 1967, providing a huge amount of data and insight into the way the solar corona works and the relationship between solar and terrestrial phenomena. Wild published more than 70 papers in this field. The heliograph also played a leading supporting role in both the Skylab missions of 1973–74 and the solar maximum mission of 1980–81, providing real-time observations of coronal activity. It was de-commissioned in 1984 to make way for the Australia Telescope and transferred to the Ionospheric Prediction Service, where it is still used today for space weather monitoring of solar activity. Now there are at least 20 ground-based radio-spectrographs operating around the world.

Although Wild wrote most of the papers, he was characteristically generous in giving credit to others, saying "I did put other people's names on them because they'd made important contributions". One, for example, was technical assistant Bill Rowe. During a period when the solar cycle was at a minimum and nothing was happening he drove down to Dapto for an 11 am appointment. Wild remarked:

Out of sheer conscientiousness he arrived at 8 am, switched on the gear and recorded the most magnificent outburst, which led to the discovery of first and second harmonics. Well, you couldn't write a paper without putting his name on it.

As he had with John Murray at Dapto, Wild always acknowledged chief electronics engineer Kevin Sheridan as the key figure in the facility's development: "Kevin and I became like Gilbert and Sullivan; we were both dependent on each other a great deal."

The Culgoora site later became the home for the Paul Wild Observatory, opened in 1988 and now a site for several major astronomical facilities.

Wild was always keen to pass on his enthusiasm for science. With George Gamow and instigator Harry Messel, he was a member of the inaugural trio who, from 1962, brought high-level science teaching to senior secondary students throughout Australia. Titled Summer School of Science, the sessions were televised live at the University of Sydney and re-broadcast in three-hour programs early every Sunday morning – a fore-runner of the programs of today’s Professor Harry Messel International Science School.