Henry Cavendish in 1784 (in an unpublished manuscript) and
Johann Georg von Soldner in 1801 (published in 1804) had pointed out that Newtonian gravity predicts that starlight will bend around a massive object.
[19][20] The same value as Soldner's was calculated by Einstein in 1911 based on the equivalence principle alone. However, Einstein noted in 1915 in the process of completing general relativity, that his 1911 result (and thus Soldner's 1801 result) is only half of the correct value. Einstein became the first to calculate the correct value for light bending: 1.75
arcseconds for light that grazes the Sun.
[21][22]
The first observation of light deflection was performed by noting the change in position of
stars as they passed near the Sun on the
celestial sphere. The observations were performed by
Arthur Eddington and his collaborators (see
Eddington experiment) during the total
solar eclipse of May 29, 1919,
[23] when the stars near the Sun (at that time in the constellation
Taurus) could be observed.
[23] Observations were made simultaneously in the cities of
Sobral, Ceará, Brazil and in
São Tomé and Príncipe on the west coast of Africa.
[24] The result was considered spectacular news and made the front page of most major newspapers. It made Einstein and his theory of general relativity world-famous.