THE EINSTEIN THEORY.

Manawatu Times, Volume XLVI, Issue 2165, 3 July 1922, Page 5

THE EINSTEIN THEORY.

AND THE COMING ECLIPSE. AUSTRALIAN EXPEDITION. LONDON, June 23. Mr G. F. Dodwell, Government astronomer for South Australia, leaves London to-morrow, via America, where he intends to visit the famous observatories, and specially to note astronomical photography as applied to eclipse work, with a view to obtaining as much success as possible for the South Australian expedition to Cordillo Downs for the forthcoming eclipse of the sun, when it is hoped to obtain confirmation of the Einstein theory of the displacement of star images when their rays pass near the sun. MINUTE MEASUREMENTS NECESSARY. Observations to detect the displacement predicted by Professor Einstein were secured by two British expeditions at the eclipse of 1919, and the results supported the prediction. But there are many people who have remained unconvinced, and are anxious for the results then obtained to be confirmed The forthcoming eclipse is not so "favourable for the purpose as was that of 1919, for the stars near the sun will be much fainter than on that occasion, and will therefore be much more difficult to photograph. Profiting, however, by the experience gained in Brazil, and using a larger instrument, it is hoped that on the present occasion results of a much higher order of accuracy will be obtained. This is particularly to be desired, since, for many years, there will not be an eclipse even so favourable for the purpose as that of next September. The effect to be measured is extremely minute, and observations of the greatest precision and highest refinement are necessary to be of any value. The displacement of the star-images is detected by comparing the photographs obtained during the eclipse with other photographs of the same region of the sky obtained at night about three or four months earlier. The images of the stars near ihe sun in the eclipse photographs will be displaced by abcut one two-thousanlth part of an inch as compared with their positions on the earlier plates. It is upon the measurement of such small displacements that Einstein's theory, with its new views as to space and time, hangs or falls! But the refineme it of modern astronomical measurement is equal to the occasion.