One hundred years ago today, May 29, 1919, the shadow of the moon swept across the Earth, crossing South America, the Atlantic Ocean and Africa (Fig. 1), and a total solar eclipse could be seen along the way.
The two observing teams are on mission to travel thousands of miles from Britain to Solabour in Brazil, South America, and Principe in Western Africa. Fortunately, both teams succeeded in measuring the positions of several stars near the black sun during the total solar eclipse.
Picture 2 shows a large prominence at the edge of the sun in a photograph they took in Solabour at that time. Fig. 3 is a picture taken in Principe, showing the positions of some stars near the sun. Fig. 4 is the equipment used by the Principe observation team at that time.
These observations provide the first evidence to support Einstein’s theory of general relativity that gravity bends light.
Sources: 1, NASA; 2, British National Maritime Museum; 3, papers of the observation team; 4, British Museum of Science.