Total solar eclipse, 29 May 1919.
© Science Museum / Science & Society Picture Library
Glass positive photograph of the corona, taken at Sobral in Brazil, with a telescope of 4 inches in aperture and 19 feet focal length. The expedition, organised by physicist Sir Arthur Eddington (1882-1944) of the Royal Observatory, Greenwich, used photographs taken during the eclipse to measure the deflection of star light adjacent to the Sun as predicted by Albert Einstein (1879-1955) in his Theory of Relativity. The year 2005 marked the centenary of publication of Einstein's Special Relativity Theory which posited that time does not exist at the same rate for everyone and everything. Special Relativity produced the equation which expresses the equivalence between matter and energy: E=mc squared. This image was donated to the Science Museum by the Greenwich Royal Observatory.