Astronomers came from the United States, Canada, New Zealand, India and Britain – journeying to places so remote that many Australians had never heard of them before their names started appearing in the press.
The scientists were there not just for the spectacle, but also in the hope their observations of the eclipse would validate Albert Einstein’s then-controversial theory of general relativity, postulated just seven years earlier.
Einstein’s theory, broadly speaking, suggested gravity can bend the very fabric of space-time itself. One possible way to test this was to photograph the background of stars both before and during an eclipse. The Sun’s gravity should bend the light from the distant stars as it passes in front of them, causing them to appear in a slightly different position – and the eclipse would allow astronomers to make this observation by helpfully blotting out the Sun’s glare.
War and weather
The first world war prevented astronomers from investigating Einstein’s 1915 prediction. But a total solar eclipse on May 29 1919 offered the first decent chance to prove him right. Britain mounted two separate expeditions in the hope at least one of them could make the necessary observations. In Sobral, Brazil, the team led by Astronomer Royal Frank Dyson suffered equipment failure. But on the island of Principe off Africa’s west coast, Arthur Eddington, despite inclement weather, successfully photographed the event.
Dyson, after viewing Eddington’s photographic plates, pronounced “there can be no doubt that they confirm Einstein’s prediction”. But many sceptics remained unconvinced.
The next suitable eclipse was in Australia on Sept. 21 1922. The famous Lick Observatory in California had used its fine 12-metre camera to photograph several previous eclipses, and director William Wallace Campbell was determined his observatory would solve “the Einstein problem” in Australia.
Campbell’s chosen location – Wallal, on the WA coast about 200 miles (320 kilometers) south of Broome, was remote and almost inaccessible. But it had virtually no chance of cloud, and the eclipse there would last longest, offering a full five minutes of totality.
Shallow seas meant the expedition’s ships could not get close to shore, and instead had to ferry the equipment ashore at high tide with the help of local Indigenous people.