Wilbur Norman Christiansen

Wilbur Norman Christiansen

Australian astronomer, pioneer of Australian radio astronomy.
Date of Birth: 09.08.1913
Country: Australia

Content:
  1. Australian Astronomer and Pioneer of Australian Radio Astronomy
  2. Career in Radio Astronomy
  3. Contributions to Solar Radio Astronomy
  4. Professional Achievements and Affiliations
  5. Professorship and Honors

Australian Astronomer and Pioneer of Australian Radio Astronomy

Wilbur Norman Christiansen was an Australian astronomer and a pioneer of Australian radio astronomy. He was born in Melbourne to a family of a priest and a music teacher. He received his education at the University of Melbourne.

Career in Radio Astronomy

From 1937 to 1948, Christiansen worked at the research laboratory of Amalgamated Wireless (Australasia) Ltd, where he was involved in the design of directional antennas for long-distance radio communication. From 1948 to 1960, he worked at the Radio Physics Division of the Commonwealth Scientific and Industrial Research Organisation in Sydney.

In 1949, Christiansen developed a new type of multi-beam radio interferometer with high angular resolution. This system consisted of linearly arranged movable paraboloids. He supervised the construction of the first such system in Potts Hill, near Sydney. Later, he designed a similar cross-shaped interferometric system known as the "Christiansen Cross". He was involved in the development and construction of radio interferometers in Westerbork (Netherlands), Saint-Michel (Upper Provence, France), Beijing Observatory (China), and Fleurs (near Sydney). He used these radio telescopes to observe the Sun's emission with high resolution.

Contributions to Solar Radio Astronomy

Christiansen studied the sources of decimeter radiation on the Sun and showed that they are related to optical details. He demonstrated that radio emission originates from dense regions of the lower corona and has temperatures of several million degrees. He also extensively studied the background radiation of the quiet Sun, constructing a high-resolution map of its radio emission and providing the first confirmation of the theoretically predicted east-west brightening of the Sun's disk.

From the start of the International Geophysical Year (July 1, 1957) until 1975, Christiansen led the publication of daily maps of solar radio emission. In 1951, soon after the discovery of monochromatic radio emission from neutral hydrogen at 21 cm wavelength by H. Ewen and E. Purcell, Christiansen, together with G. V. Hindman, conducted a survey of hydrogen emission and obtained the first radioastronomical evidence for the existence of spiral arms in the Milky Way.

Professional Achievements and Affiliations

Christiansen was the Chairman of the Australian National Committee for Radio Science from 1960 to 1976. He served as the President of the Radio Astronomy Commission of the International Union of Radio Science from 1963 to 1966 and as its Vice President from 1972 to 1978. He was also the Vice President of the International Astronomical Union from 1964 to 1970 and its President from 1978 to 1981. Christiansen was elected as a member of the Australian Academy of Science in 1959.

Professorship and Honors

Christiansen was a professor of electrical engineering at the University of Sydney from 1960 to 1978 and held an honorary professorship at the same university from 1978. Throughout his career, he made significant contributions to the field of radio astronomy and received numerous honors for his work.

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