Joseph L. Pawsey

Joseph Pawsey
Pawsey as a research physicist inCSIRO
Born	Joseph Lade Pawsey (1908-05-14)14 May 1908 Ararat, Victoria,Australia
Died	30 November 1962(1962-11-30)(aged 54) Sydney, Australia
Alma mater	University of Melbourne Sidney Sussex College, Cambridge
Known for	Early leadership of radio astronomy andionospheric physics, Radio observations of the Sun and Galaxy
Awards	Fellow of the Royal Society Hughes Medal(1960)
Scientific career
Fields	Radio astronomy
Institutions	CSIRO

Joseph Lade Pawsey(14 May 1908 – 30 November 1962) was an Australian scientist, radiophysicist and radioastronomer.

Education

Pawsey was born inArarat, Victoriato a family of farmers. At the age of 14 he was awarded a government scholarship to study atWesley College, Melbourne,followed by a scholarship to study at theUniversity of Melbourne.In 1929, he earned hisBachelor of Sciencedegree from the university, followed by aMaster of Sciencein Natural Philosophy in 1931.

Pawsey was then awarded an Exhibition Research Scholarship to study atSidney Sussex Collegeat theUniversity of Cambridge,where he worked under the direction ofJ.A. Ratcliffe.He studied the effects of the ionosphere on radio propagation and his discovery of the presence of irregularities in theKennelly-Heaviside Layerproved vital to the later development of this branch ofionospheric physics.In 1935, he was awarded aPhDfrom Cambridge and in September of that year he married Greta Lenore Nicoll, a 32-year-old Canadian.

Pawsey then became a research physicist atEMIuntil 1939.

Career

In February 1940, Pawsey returned to Australia to work at the recently formed Division of Radiophysics in CSIR (later renamedCSIRO). One group he led developed amicrowaveset for theRoyal Australian Navywhile another group under his direction investigated the 'super-refraction' of radio waves in the Earth's atmosphere.Pawsey continued as a research physicist at the Division of Radiophysics until 1962, becoming assistant chief of division in 1952.

At the end ofWorld War IIhe became a pioneer of the new science ofradio astronomy,his interest being stirred by the discovery of radio waves from theGalaxyand by reports of intense interference in metre-wave radar receivers caused by disturbances on theSun.To investigate the latter Pawsey, withRuby Payne-Scottand Lindsay McCready, used an existingRoyal Australian Air Forceantenna atCollaroy Plateau,a northernSydneysuburb.In addition to confirming that the Sun was a source ofradio noisetheir data also showed that the temperature in some regions of the Sun were as high as one million degrees. This temperature was far higher than was thought possible at the time. Work by the physicistDavid Forbes Martynshowed that temperatures peak in the Sun'scoronaat one million degrees. The observations with the Collaroy antenna not only marked the beginning of radio astronomy in Australia, but also the first time radio astronomy had provided important information on a problem in traditional optical astronomy.

The introduction of interferometry was probably Pawsey's most important contribution to radio astronomy.In early 1946 he turned his attention tosunspotsas a source of strong fluctuating radio noise. To overcome the limitations of the available antennas, Pawsey usedsea interferometryand began observations atDover Heightswhich provided a better vantage point than Collaroy. The observations confirmed beyond doubt that sunspots were the source of the strong increase in radio noise. This work was confirmed four months later by radio astronomers atCambridge Universityled byMartin Ryle.

Members of Pawsey's group invented techniques that were subsequently incorporated into general use in radio astronomy and made important discoveries about the discrete sources of radio emission in the Milky Way and external galaxies.Pawsey did some work on his own, but his main focus was on guiding and administering his research teams,which worked in comparative isolation and sometimes in competition with each other. He was straightforward, honest and humble, and scrupulous in acknowledging his colleagues' achievements.His subordinatePaul Wild,who in 1971 became division chief, said:

Joe Pawsey was the... father of radio astronomy in Australia.... His influence on the growth of radio astronomy in Australia was great because… he just provided ideal conditions, an ideal environment to allow everyone to use their own initiative.... [He] was a wonderfully inspiring leader, very self-effacing and taking no credit for himself, and he was a delight to work under.... [His advice] was often very perceptive, very good ".

International authorities gave much credit to his leadership. In 1963, in his introduction to the Utrecht Symposium on the Solar Spectrum, Professor M.G.J. Minnaert remarked:

The history of solar radio-spectroscopy is mainly the history of Australian work on this subject. At each meeting of theIAU,at each important symposium on radio-astronomy, highly competent specialists such as Wild, Smerd and Christianson, headed by the dynamic personality of... Pawsey, were able to announce spectacular progress.

In 1952, Pawsey became president of the Radio Astronomy Commission of theInternational Astronomical Union,serving until 1958. From 1960 until 1961 he was president of the Australian Branch of theInstitute of Physics.He was appointed as director of the USNational Radio Astronomy Observatoryin 1962, but he died in Sydney of abrain tumourbefore he took office.He was survived by his wife, two sons and a daughter.

The craterPawseyon theMoonis named after him.Also named after him is thePawsey Supercomputing Centre,the home ofpetascalesupercomputingfacilities and expertise to support internationalSquare Kilometre Arrayresearch and other high-end science (based at Technology Park in thePerthsuburb of Kensington).

Awards and honours

• Thomas Ranken Lyle Medal,1953.
• Fellow,Royal Society,1954.
• Matthew Flinders Medal and Lecture,1957
• Royal SocietyHughes Medal,1960.
• Foundation Fellow of theAustralian Academy of Science,1954.Fellow,Australian Academy of Science(1954).
• Honorary DSc from the Australian National University, 1961.
• ThePawsey Medalof the Australian Academy of Science, awarded since 1967, commemorates his contributions to science in Australia.
• The Pawsey Memorial Lecture is delivered annually by a distinguished scientist.

Bibliography

• R.N. Bracewell and J.L. Pawsey,Radio Astronomy,1955, Clarendon Press.
• J L Pawsey et al., "Cosmic radio waves and their interpretation", 1961,Rep. Prog. Phys.24.

See also

• Joan Maie Freeman
• Ruby Payne-Scott

External links

• Encyclopedia of Australian Science