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Centenary of Solar Eclipse of 1919 - Sobral

In 2019 it will be celebrated all around the world the centennial anniversary of the solar eclipse observed on May 29th, 1919, which has constituted an extraordinary event for science. The measure of the starlight deflection by the Sun confirmed Einstein´s General Relativity Theory that deeply changed our conception of the Universe.  Decisive observations were done in Sobral (Ceará, Brazil), and also on Principe Island, by British astronomers. The results were publicly disclosed in London on November 6, 1919. After that day newspapers around the world reported headlines announcing a revolution in science: Einstein`s theory had supplanted Newton`s gravitational theory. That event made Einstein, a scientist formerly known only to his colleagues, the best-known scientist of all time. 

In 1911 Einstein predicted that the light could be deflected when passing near a massive celestial body and proposed that this deflection could be measured in a total solar eclipse. In 1919, two British expeditions were organized: one, headed by Arthur Eddington, went to Príncipe Island; the other one, under Charles Davidson and Andrew Crommelin, went to Sobral. After months of careful analysis, Frank Dyson, Eddington and Davidson exposed the final results: the measures showed a good experimental agreement with that predicted by Einstein, 1.74 second of arc for the deflection angle of the light. According to Newton's theory the deflection should be half of that.

How to Get Involved?

In 2019 many celebratory activities are being held in Brazil, Portugal and Príncipe Island. In Sobral there is an intense participation of the population and the local authorities decreed the Year of Science in the city. Many scientific, educational and public communication of science events will take place in Sobral and other Brazilian cities. Videos and materials for the media and social networks are being produced. An international event, to be attended by astronomers, physicists, historians of science, teachers, students etc., will take place in Sobral on the day 29 May 2019. It would be very important that activities, related to the centenary of this remarkable scientific event, could also be organized in other countries within the actions scheduled for the International Day of Light 2019.



The commemorative activities are being organized by the Brazilian Society for the Advancement of Science and other Brazilian scientific societies and institutions, as the Brazilian Astronomical Society (SAB), the Brazilian Society of Physics (SBF) and the National Observatory, as well as by the local commission, which includes the mayor and secretaries of Sobral, universities, Planetarium of Sobral, Museum of the Eclipse and other local institutions of the State of Ceará.


Ildeu de Castro Moreira

Cláudia Linhares Sales

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