1922 Solar Eclipse in Australia

Testing Einstein's Theory

Equipment being prepared on the SA eclipse expedition. This and the eclipse photograph come from the papers of Kerr Grant.

A total solar eclipse in Australia in 1922 provided scientists with an opportunity to confirm the experimental 'proof' of Einstein's general theory of relativity that had been provided by Eddington's observations in 1919. Independent expeditions mounted by the SA and NSW observatories both aimed to test Einstein's prediction that light passing near massive bodies such as the sun would appear to be bent.(1)

The professor of physics at Adelaide University, Kerr Grant, assisted the SA effort, while A.D. Ross, from the University of Western Australia, joined an American operation organised by the Lick Observatory at Wallal in WA. This was not seen as purely an academic question, G.H. Knibbs, Director of the Commonwealth Institute for Science and Industry, justified the expense of the expeditions by arguing that such studies of the sun 'may yet prove to be... of great practical importance'.(2)

The press and the public were, if anything, even more enthusiastic about the eclipse tests. The visiting astronomers from the Lick Observatory were accorded celebrity status as they made their way through the eastern states. In Melbourne they were feted by the Lord Mayor and the Federal ministry. Members of the party also gave well-attended talks on their work in the Town Hall and at the University.(3) The Government was keen to be seen to be involved in such undertakings; one report commented:

Though no Commonwealth expedition has been arranged to make observations of the solar eclipse, the Commonwealth Government, the Minister for Home and Territories (Senator Pearce) explained on Saturday, had incurred considerable expense in facilitating the operations of visiting expeditions.(4)

It also stressed that the eclipse tests were 'crucial' in the establishment or refutation of relativity. C.A. Chant, the leader of a Canadian mission to observe the eclipse, stated: 'we hope definitely to settle whether the Einstein theory is correct or not'.(5) While it was reported that Dr Campbell of the Lick expedition hoped to determine whether the Einstein theory 'represented a fact of nature'.(6) Indeed, the eclipse tests acquired such a public status that J.M. Baldwin, the Victorian Government astronomer, felt it necessary to explain that as his own expedition 'was hurriedly arranged by private means, no attempt could be made on the Einstein theory'.(7)

Notes:

(1) G.F. Dodwell and C.R. Davidson, 'Determination of the Deflection of Light by the Sun's Gravitational Field from Observations made at Cordillo Downs, South Australia, During the Total Eclipse of 1922 September 21', Monthly Notes of the Royal Astronomical Society, vol. 84, 1924, p.150; W.E. Cooke, 'Total Solar Eclipse of 1922 September 21. Observations by the Sydney Observatory Expedition at Goondiwindi, Queensland', Monthly Notes of the Royal Astronomical Society, vol. 83, supll. 1923, p.511; Jeffrey Crelinsten, 'William Wallace Campbell and the "Einstein Problem"; An Observational Astronomer Confronts the Theory of Relativity', Historical Studies in the Physical Sciences, vol. 14, pp.75-76.

(2) G.H. Knibbs, 'Science and Its Service to man', Presidential Address, AAAS Report of the 16th Meeting, Wellington 1923, p.12.

(3) See Argus, 4 August 1922, p.8; 8 August 1922, p.8; 9 August 1922, p.11; 10 August 1922, p.5.

(4) Argus, 7 August 1922, p.6.

(5) Argus, 25 July 1922, p.8.

(6) Argus, 7 August 1922, p.6.

(7) Argus, 23 October 1922, p.3.