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Nicolaus Copernicus is often cited as the man who gave us the heliocentric theory of the solar system, but there is some question as to the crucial influence that earlier Islamic scientists may have had on many of his ideas about the motion of the Earth.

F. Jamil Ragep, a professor of history of science at the University of Oklahoma, gave a lecture at the University of Alberta about similarities to be found in the theories of the 16th-century Copernicus and his 13th-century Islamic astronomer counterparts Nasir al-Din al-Tusi. That the two astronomers shared similar thoughts about the matter indicates some sort of exchange of ideas, said Ragep, noting that chapters in Copernicus' book, On the Revolution of the Heavenly Bodies, correspond closely with Tusi's own astronomical theories.

"People have been talking about this at least since (J.L.E) Dreyer - there has been a long history of knowing about the connection," he said. Dreyer's classic text book, The History of Planetary Systems, was published in 1906.


Perhaps al-Tusi's greatest gift to the world of astronomy was his invention of the 'Tusi Couple' - a geometrical device that the Persian scholar used to resolve problems he had found with the ancient Greek scientist Ptolemy's models. As old documents have shown, Copernicus used the Tusi Couple in his own lunar theories.


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