The Trial Of Galileo
The Trial of Galileo
Copernicus's De Revolutionibus of 1543 was dedicated to the Pope; yet ninety years later (1633) Galileo was tried by the inquisition for espousing Copernican views. How did this come about?
Prior to the publication of De Revolutionibus, astronomical theories proposed that the earth was the centre of the universe and all the planets revolved around the earth. This was a view that was supported by both Aristotle and Ptolemy although Ptolemy's work was based upon observations and scientific methods as opposed to Aristotle who was in effect theorising based upon religious belief. I shall outline the essential content of the De Revolutionibus and explain why it took so long for the church to condemn his book and then try Galileo for heresy as a result of his supporting Copernican ideas.
Copernicus was studying and writing during the Renaissance and arguably the Scientific Revolution. The Renaissance was a time of rebirth of old ideas and a new way of looking at things not just in the areas of science but throughout literature, arts and many other areas. It was a time when new ideas did not seem to provide solutions to all the questions that were being asked.( ) Copernicus proposed a new system of planetary motion that had the sun at the centre of the universe rather than the earth. However contrary to popular belief, this was not a new and revolutionary idea. The ancients had proposed such a solution, most notably from Aristarchus who argued that it was more plausible for the sun to be at the centre rather than the earth. However Copernicus makes no mention of Aristarchus in De Revolutionibus. Not long before Copernicus began writing, Cusa suggested this again, and it is argued that this may be where Copernicus got early inspiration from, although this is not proven. ( ) It was in the rest of his writing that Copernicus suggested ideas that were considered to be revolutionary. According to the Copernican system not only was the Earth revolving around the sun; it was revolving on its own axis. This was later to replace the idea that it was the stars that were revolving. Copernicus proposed that the earth revolved on its own axis once every day and orbited the sun throughout the period of a year. Copernicus hesitated in the publishing of the book as he was afraid that it may be heretical, even though the book when it was eventually published in 1543 was dedicated to Pope Paul the 3rd. At the time of his writing, Aristotelian physics were popular, and it was a difficult task to convince people that the heavens were not perfect, but were the same as the earth and that the earth was constantly moving. ( )
Many historians have argued that Copernicus initiated an astronomical revolution, which led to a whole new approach to looking at the heavens. This revolution was taken up by Galileo towards the end of the sixteenth century. Galileo believed in the Copernican theory that the Sun was the centre of the universe. It was this firm belief that eventually led to his trial for heresy.( ) The main question is what happened in the years between the publication of De Revolutionibus and the publication of firstly Sidereus Nuncius (1610) and the Dialago [Dialogue Concerning the Two Chief World Systems] (1632) I am firstly going to discuss some of Galileo's main astronomical discoveries and then highlight the changes in the seventeenth century that led to the trial of Galileo for heresy.
Galileo admitted to Kepler as early as 1604 that he was a supporter of Copernicans, but at this time his field of study was not astronomy. However Galileo remained silent about this belief for a number of years, probably heavily influenced by the execution of Giordano Bruno in 1600 for heresy. He was more interested in the study of mechanics and motion, and upon overthrowing the Aristotelian view of motion.( ) Galileo only became interested in the field of Astronomy after hearing of the invention of the telescope although he made one contribution to astronomy in 1604. He observed the phenomenon of the Nova or new star, which of course played an important