Friday, 23 January 2009

Galileo : Blinded by the Light

by Kathryn Hadley

A group of Italian and British scientists have recently renewed their appeal to exhume the body of Galileo Galilei (1564-1642) to carry out DNA tests in order to determine the extent to which his vision problems affected his findings. The scientists told Reuters last Thursday that the tests would help to resolve some of the unanswered questions about the health of the Tuscan physicist, mathematician, astronomer and philosopher.

Throughout the second half of his life Galileo suffered from intermittent eye problems and the last two years of his life he was totally blind. His findings and his presentation of heliocentrism as a proven fact in particular, resulted in a papal trial in October 1632. He was accused of heresy and spent the last years of his life under house arrest on orders of the Roman Inquisition. Dr Peter Watson, president of the Academia Ophthalmologica Internationalis and consultant to Addenbrooke's University Hospital, Cambridge, suspects that he may have suffered from unilateral myopia, uveitis (an inflammation of the eye’s middle layer) or a condition called creeping angle closure glaucoma. Watson believes that:

"There were periods when he saw very well and periods when he did not see very well […] A DNA test will allow us to determine to what measure the pathology of the eye may have 'tricked' him".

According to Paolo Galuzzi, director of the Institute and Museum of the History of Science in Florence, who has published widely on the scientists and engineers of the Renaissance, including Galileo, and on the birth and history of the historiography of science, such illnesses may have been the source of one of Galileo’s most significant errors. Galileo believed that Saturn was not round, but had an irregular inflated side. His bad eyesight may have caused him to mistake Saturn’s gaseous ring and to conclude instead that Saturn was a planet with two moons as satellites. In Galuzzi’s words:

"This was probably a combination of errors. He probably expected to find satellites and his eyesight may have contributed to some confusion [...] If we knew exactly what was wrong with his eyes we could use computer models to recreate what he saw in his telescope [...] We can formulate a mathematical model that simulates the effects it would have had on what he saw and using the same type of telescope he used we can get closer to what he actually saw […] We only have sketches of what he saw. If we were able to see what he saw that would be extraordinary".

During the first 100 years after his death, Galileo’s remains were hidden in a bell tower room of Santa Croce Basilica in Florence because the Church opposed a proper burial. He was reburied in the main body of the basilica in 1737 where a monument was erected in his honour. His bones were stored together with those of his disciple, Vicenzo Viviani, and those of an unknown woman. DNA tests would also help to determine if they are, as Galuzzi believes, those of one of his three illegitimate children, Sister Maria Celeste .

The scientists are still waiting for permission from the Church to exhume the body. The Institute of the History of Science will then require 300 000 Euros to finance the tests.

For more information on the links between Galileo’s discoveries and the paintings of his Italian contemporaries, read our article
A New Heaven - Galileo and the Artists
Who was the real inventor of the telescope, the crucial instrument in all Galileo’s observations? Find out more in our article Who Invented the Telescope?
Visit our History of Science focus page to find out more about the History of Science and some of its greatest icons.

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