Galileo Galilei, a professor of mathematics at the University of Padua, directed a self-produced spyglass at the heavens setting off a chain of events that according to Albert Van Helden, shook “the intellectual edifice of Europe to its foundations.” Through this spyglass, which later came to be known as telescopium (telescope), Galileo was able to look to the heavens with more clarity than the naked eye and thus make observations that had never been made before. He published some of his initial observations in his astronomical journal, Siderius Nuncius. The observations were as follows: studies of the moon and the fact that it is not perfectly spherical but had mountains and valleys likening it to the earth, observation of Nebula and stating that they were actually stars too far and close together to be seen by the naked eye, and four fixed stars near Jupiter that later came to be known as Jupiter’s moons. Although Galileo was able to make these observations and provide proof in his journal, most scholars and mathematicians were still sceptical. Galileo faced many difficulties in trying to prove his theories to the general as well as the renowned public, among which, the optical and philosophical were the greatest.
The first of his difficulties was the very means of Galileo’s discoveries: the spyglass itself. In the conclusion, Van Helden states:
“The spyglass presented methodological and epistemological problems. The prevailing Aristotelian methodology was based on deductions and inferences from information gathered by means of the unaided senses… Galileo’s claim was that the spyglass revealed phenomena that were invisible to the naked eye. This was intriguing but how could one be certain that the instrument did not deceive Galileo and that the phenomena really did exist in the heavens?” (90)
Although today it is standard to accept technologically advanced devices readily, the telescope used by Galileo was one of the first instruments that could amplify the senses and as a result was open to question. Another difficulty in proving Galileo’s studies of the heavens was that his telescope was by far superior to the spyglasses that were circulating around the globe at the time. It was also quite difficult to make and as a result, producing these spyglasses was a painstaking and not always productive process. this also meant that other scholars and scientists would be unable to verify Galileos claims. Although this worked in his favour to ensure that he was the first to make and publish such discoveries, it also worked against him such that for quite a while, he was rejected and cast as a madman seeking glory by any means possible.
Another one of the difficulties that Galileo had to overcome was the controversy it created with regards to the then widespread and cherished cosmological ideas that supported the Aristotelian view of the solar system being geocentric. It also flew in the face of the Church’s belief that the heavens were perfect and that the earth’s imperfections could not be mirrored in celestial bodies. According to Van Helden, “One could not maintain the perfection of the heavens if one accepted Galileo’s claims that the Moon was covered with mountains and valleys like the Earth.” (92) The evidence provided by the telescope could not be backed by the Aristotelian view of the universe and this caused contention between the Aristotelian hypothesis and the Copernican hypothesis, which was better suited to Galileo’s heavenly sightings.
Due to these various differences in opinion, many were dubious of Galileo’s claims. One such individual was Martin Horky from Bohemia. Horky was a young associate of the internationally renowned astronomer, Giovanni Antonio Magini and was able to observe the sky with Galileo’s telescope in late April. In a letter to Johannes Kepler, the Imperial Mathematician in Prague, Horky seemed suspicious of Galileo’s celestial observations and referred to them as fictitious. He even went so far as to describe Galileo as ungrateful and full of himself. Although Galileo received dissension from a lot of scholars and mathematicians like Horky, there were a few colleagues that still supported him. One such person was Johannes Kepler. A supporter of the Copernican theories of the universe, he was quick to fall behind Galileo’s theories even before having observed these theories for himself. Another stout and powerful supporter of Galileo’s was the Fourth Grand Duke of Tuscany, Cosimo II De’Medici. He provided Galileo with a position at the Tuscan court as mathematician and philosopher of the Grand Duke and even alerted and instructed Tuscan ambassadors at foreign courts to promote Galileo’s discoveries. Galileo was also given access to the Tuscan treasury in order to produce more spyglasses to provide the ambassadors with. By the end of 1610, most of Galileo’s discoveries had been verified by multiple independent observers and even the spyglass had been established as an instrument that did not deceive but truly enhanced the visual senses.
These multiple discoveries had not been overlooked by church officials. “The implications of the discoveries were not lost on the men who concerned themselves with matters of religious orthodoxy, for Aristotelian philosophy and Christian theology were closely intertwined.” (Van Helden, 112) In a letter to Cardinal Robert Bellarmine on 24th March 1611, the Jesuit mathematicians, Fathers Clavius, Grienberger, Lembo and Maelcote expressed their thoughts on Galileo’s heavenly observations.
After having observed the night sky with the spyglass, they came to the conclusion that it did indeed enhance human vision and many stars did appear in certain nebula but not all nebula necessarily consisted of minute stars. They were also unable to deny that the moon indeed had inequalities but while some agreed with Galileo’s observations of this satellite’s rough surface, others chalked that up to the varied density of the moon in certain parts. However, one observation that was unanimously unable to deny was that Jupiter did indeed have four moons circling the planet and that they weren’t fixed stars.
Thus, although it took a while, Galileo’s discoveries and observations were able to gain merit and this changed the course of scientific and astronomical research in history.