Jack Oughton - Galileo, The Telescope and The Church.doc
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  • 1. Jack Oughton Introduction In 1604 the Western world witnessed evidence of the unspeakable, evidence of the changing nature of the cosmos. In the foot of Ophiuchus a new star had appeared, brighter even than Jupiter, and it was visible for a full18 months, before fading away. The old ways proclaimed that the heavens where immortal and unchanging, but here was direct evidence of nature contradicting that. Today we know it as Kepler’s Star, we witness it as the remnants of a supernova, but in those dark times it was an omen, and almost literally a metaphor of the death of the Aristotelian view of the Universe that Europe had been clinging to for millennia. One man who watched that new star with interest would devote much of his life to the pursuit of scientific truth. In 1605 he delivered 3 lectures at Padua University, in which he argued that parallax measurements proved that the new star was beyond the moon in length, and that therefore change did occur in the heavens. I argue that Galileo’s Galilei’s decades long struggle with the unchanging paradigm of the Ancients brought about the true spirit of the scientific revolution, which we hold true to today, which is not to believe or assume, but to always question; the transition from faith to science. It is believed that Galileo had held at the minimum an interest in the Copernican hypothesis at least as far back as the early 1590s. In 1595, he used ideas based on Copernican motions of the earth to devise a hypothesis to explain the motion of the tides. He would later expand upon this in his seminal Dialogue on the Two Chief World Systems. In 1597 he wrote to Kepler; another man who would reshape the scientific world in his own way. Galileo wrote; “I have for many years been a partisan of the Copernican view... I have collected many proofs, but I do not publish them, because I am deterred by the fate of our teacher Copernicus who…was ridiculed and condemned by countless people...” Galileo waited patiently for more than a decade for his opportunity to further prove and test his beliefs, and in 1609 with the discovery of an instrument that allowed "seeing faraway things as though nearby” he took it. A Tool To Smash A Paradigm In the spring of 1609 after a single night devoted to consideration of the laws of refraction, Galileo had discovered how to create his own telescope, constructing a triple magnification spyglass from lenses he purchased in spectacle makers' shops. Whilst others had done the same thing; what set Galileo apart was his excellent experimental skill, born of years of scientific experience, and working with different lenses, he realized that, high magnification required a weak convex lens and a strong concave lens. His problem was that opticians only made glasses in a narrow range of strengths, and three or so was the best magnification available with these off the shelf lenses. So, once again he applied his focus to learning another skill, and taught himself the art of lens grinding. In applying his custom ground lenses, he discovered a way to improve the instrument’s magnification, producing increasingly powerful telescopes over a matter of months. By August he had presented an eight-powered instrument to the Venetian Senate and by October he had constructed a telescope of twenty times magnification. By 1610 Galileo was realizing the wondrous possibilities of this new scientific tool he had refined, and using it to discover further evidence that demolished Aristotle’s now tenuous paradigm. As well as possessing the most powerful telescope in the world, he was the first person to do what now appears its most obvious use, and turn it to the stars. What he saw there supported Copernicus’ hypotheses beyond the shadow of a doubt, and also made him a dangerous threat to those who took the beliefs of the ancients, or the Bible to be dogma.
  • 2. The Moon In November 1609 Galileo pointed his improved telescope towards the moon for the first time. From November 30th until December 18th of that year, he examined and drew the face of the moon in great detail. He found that the Moon was not the perfect unperturbed sphere that Aristotle would have supported, a closer look at the surface revealed that, “the spots all have a dark part on the side toward the Sun while on the side opposite the Sun they are crowned with brighter borders like shining ridges." (Starry Messenger, p 41) From these observations, Galileo deduced that he was observing the shadows cast by an uneven surface, consisting of valleys, plains and mountains much like the surface of the Earth. This conclusion was revelation, how could a heavenly body have an imperfect surface? Could it be that the earth was also a heavenly body as well? Where was heaven and what was the extent of the spread of the earthly corruption? Although this was not evidence directly supporting the Copernican heliocentric theory, it challenged the Aristotelian and set the theme for a number of more important discoveries that would support Copernicus. Jupiter Two months later, on January the 7th Galileo made the discovery of three of Jupiter's four largest satellites; Io, Europa, and Callisto. On the 10th Galileo observed that one of them had disappeared, which he attributed to it moving behind Jupiter. 3 days later he discovered Ganymede, the last of what are now known as the Galilean moons. This discovery of satellites orbiting Jupiter directly supported the Copernican hypothesis, which stated that “There is no one center of all the celestial circles or spheres”. Firstly, it was contrary to the orderly geocentric model of the universe, in which all celestial bodies circled around the Earth. This argument suggested that given the moon orbited the Earth, if the Earth then orbited the Sun, the Moon would be left behind. Moons orbiting around Jupiter implied that a planet could orbit another body without leaving behind any moons that were in turn orbiting it. Secondly it was the discovery of new bodies in the universe that according to the old theories simply shouldn’t have been there, the crystalline sphere that Jupiter traversed across should have been shattered by these new interfering bodies. Naturally, this was all a bit too much too soon, and many prominent academics simply didn’t believe him, but his continued observations of the moons meant that by mid 1611, he was able to accurately predict where each moon would be, and all the unbelievers had to do was stare down the telescope (and many refused to)1… In February Galileo also made some star maps, including the Pleiades. Although not of much significance compared with what he was about to unearth, the discovery of more stars in the heavens than where previously known suggested an infinite universe, lending support to an ancient Greek argument against Aristotle on the plurality of worlds, first proposed by the philosopher Thales. However, verifying Galileo's discoveries was initially difficult for anyone without access to Galileo's uniquely powerful telescope, and in the spring of 1610 no one else had the capability to observe the satellites of Jupiter. It would be about six months before others had access to instruments powerful enough to see Jupiter's moons, and by then Galileo was already working on the next big thing… Venus 1 Galileo complains to Kepler in a letter dated 19th August 1610 of philosophers who “refuse to look” (Baumgardt, 1953)
  • 3. In September of 1610, Galileo turned his telescope upon Venus. He noticed that it exhibited a full set of phases, similar to that of the Moon. Ptolemy’s geocentric hypothesis predicted that only crescent and new phases could be observed, Venus was supposed to remain between the Sun and Earth during its orbit around the Earth. However, Copernicus’ heliocentric model predicted that all phases would be visible since the orbit of Venus around the Sun would cause its illuminated hemisphere to face the Earth when it was on the opposite side of the Sun and for it to face away from the Earth when it was in between the sun and earth. Galileo's observations of the phases of Venus proved that it orbited the Sun, and this effectively falsified the Ptolemaic system beyond any shadow of doubt. In March of 1610 Galileo hurriedly published his brief treatise, The Starry Messenger. It explained the new discoveries that he had made with his telescope: the shape of the moon’s surface, satellites orbiting Jupiter, and the resolution of what nebulae into collections of stars too faint to see individually. Most importantly, for the first time he publically declared that the planets moved around the sun. (Machamer, 1998). In 1613 Galileo began to tutor students on the Copernican theory. Sunspots In April of 1612 the searching gaze of Galileo’s telescope focused upon the face of the sun. In 1613 he published his Letters on Sunspots, in which began a great argument with the Jesuit Astronomer Christoph Scheiner by disproving Scheiner’s hypothesis that sunspots where actually planets revolving around the sun, as argued under the pseudonym Apelles in Three Letters on Solar Spots. Galileo pointed out that by moving together, and moving slowly, sunspots could not be planets. He also pointed out their irregular shapes how they formed and disappeared at random. Lastly he mentioned the foreshortening of the spots as they approached the edge of the solar disk. Most importantly on pages 27 to 36 Galileo also began to formulate a geometrical argument for Copernicanism based on the motion of sunspots, but never finished it. However he did write “I tell you that also, no less than the horned Venus agrees admirably with the great Copernican system. Favorable winds are now blowing on that system… (Cropper, 2001). The implications of Galileo’s work here not only prevented any ‘saving’ of the theory, but started one of many feuds that would be characteristic of his later fame in life, and where the first insult to the Jesuit order he would make. And yet it moves... As with countless other times in history, new and radically different ideas, no matter how convincing, cannot simply be accepted without some level of resistance. Galileo was a proud man, driven to defend his Copernican position against anyone who would argue with him, or to uncompromisingly criticize anyone whom he disagreed with. At the beginning of the paradigm shift, there was an abundance of people for him to criticize, argue and disagree with, and a worldview to change. In tandem with his growing notoriety, scattered resistance to Galileo began to come from all over Europe. In June of 1610, a young Lutheran student of Kepler’s, Martin Horky, published A very short excursion against the Sidereal Messenger. Interestingly it was more of a character assassination upon Galileo himself, rather than Copernicus, claiming Galileo had invented the Jovian moons due to a “thirst for gold”, and other slanderous character attacks. (Reston, 2000) The next ineffective dig, this time upon Copernicanism, came from Francesco Sizzi, a Florentine
  • 4. astronomer. In Dianoia Astronomica, Optica, Physica, he argued partly from scripture and partly from mathematics. In part of his illogical argument Sizzi claimed; ”the satellites are invisible to the naked eye and therefore can have no influence on the earth, and therefore would be useless, and therefore do not exist”. These and other small criticisms where no match for the amount of prestige Galileo was now enjoying and number of influential friends he had made in his public life. The first organized resistance came from a group, which Galileo contemptibly referred to as the "Pigeon League" named after Lodovico delle Colombe, an Aristotelian professor of philosophy. In 1611 Lodovico published a tract that really muddied the waters in the connection between Christianity and the Aristotelians, Against the Motion of the Earth. Although it did not implicate Galileo directly it argued against Copernicus from scripture. Initially the League was comprised of Aristotelian scholars whom he had offended in public debates with his sarcastic and brutal style of argument, such as Cesare Cremonini, who refused to look down his telescope! Later it expanded to allow anyone with a grudge against Galileo in it. It is believed that this league is responsible for creating the real trouble for Galileo, its members where those who brought his argument on the passage Joshua 10: 22-24 to the attention of the Catholic Church, a far more formidable enemy. The Catholic Church had a lot invested in the belief system it enforced and was built upon, the scripture was seen as simply correct and anything that threatened to disprove it was dangerous. Copernicus’ belief in a moving earth contradicted the scripture, for example in Psalm 104:5 the Bible states; "…the LORD set the earth on its foundations; it can never be moved." If Galileo could prove Copernicus right, he would also disprove the infallibility of the Bible. Seeing as the word of God was supposed to be perfect, the Catholic Church had everything to lose here. The Church was an incredibly powerful force at the time, both in its grip on thinking, and on what it could do in its self appointed position. Galileo just didn’t face resistance from the most powerful organization of the era, but from an entire deeply entrenched philosophy and belief system that had endured for over fifteen centuries, if he wanted to a challenging foe to disagree with, this was undoubtedly it. In December of 1613, after a debate in which a former student of Galileo’s, Benedetto Castelli defended the Copernican system, Galileo wrote a letter congratulating Benedetto and in which he stated that it was a mistake to interpret passages from scripture literally. He later expanded this letter, and addressed it to the Grand Duchess Christine, a defender of scripture and one of his powerful patrons mentioning "I hold that the Sun is located at the centre of the revolutions of the heavenly orbs…” This could have been a step too far. These words would later be used against him in his trial by the Inquisition. The first attack on Galileo from the pulpit came in December 1614, from a young Dominican priest named Tommaso Caccini, also a member of the ‘pigeon league’. Tommaso delivered a furious sermon on the miracle of Joshua, and preached that it was heresy to support Copernicanism as it violated scripture. Later, in 1615 another Dominican (and pigeon), Niccolo Lorini, filed a written complaint to the Inquisition regarding Galileo's support of Copernican views. As proof he enclosed a copy of Galileo's letter to Benedetto Castelli. A few weeks later, on March 19th, Caccini traveled to the Inquisition's offices in Rome to denounce Galileo’s Copernicanism and various other alleged heresies supposedly being spread by his (growing number of) supporters.
  • 5. In spite of this negative attention from members of the church, in 1616 Galileo wrote up a treatise addressed to Cardinal Alessandro Orsini in which he claimed proved the earth moves. He argued that the sloshing of the tides was caused by a rotation of the earth, building on his previous tidal works. This was another overt piece of support for Copernicanism (“The earth… performs a complete rotation on its fixed poles in a daily motion”). This did nothing to improve his growing problem with the church. Compromise In 1616 the Church decided to take the Tychonic model of the Universe, as a way to reconcile the phases of Venus with literal interpretation of scripture. In this system, all the planets orbited the Sun, which itself orbited the earth. Despite Tycho’s attempts to engage Galileo in debate regarding this system, Galileo in an unusually non-conflictive way, did not even consider it serious enough to mention in his next work The Dialogue... Prelude To The Trial One month after goading the church with his new tidal thesis, a Vatican commission decided that the tenets of Copernicanism where “foolish and absurd and formally heretical”. On February 25, 1616, the Inquisition met and received instructions from Pope Paul to direct Galileo not to teach or defend or discuss Copernican doctrine. The day after, on orders of the Pope Paul V, Cardinal Bellarmine called Galileo to his residence and administered a warning; not to “hold or defend the Copernican theory”. Later, in March the Church also suspended the distribution of Copernicus’ book De Revolutionibus until further “corrected”. Although now prevented from supporting Copernicanism directly, Galileo continued his attack upon Aristotelian philosophy in 1623 with the publishing of The Assayer. This book was direct criticism of a treatise on the comets of 1618 by Orazio Grassi, a Jesuit mathematician of high regard. Galileo argued that the comets where actually optical illusions, and in this case was wrong. This was the second time he had criticized the Jesuits, and further strained his relationship with the Catholic Church. The Trial: In 1632, the world had changed. Cardinal Bellarmine was now Pope Urban VIII and Galileo had just published The Dialogue. Urban had requested that Galileo write a book which presented balanced arguments for Heliocentrism. But through the foolish character of Simplicio, Galileo really had taken it too far this time. Simplicio used Urban’s favorite argument that God could produce any effect He wanted, so if He wanted to make a fixed Earth appear as if moving, then it was an entirely possible explanation. The book was unmistakably biased in favour of the Copernican system, violating Galileo’s warning from 1616 not to defend Copernicus, and more importantly it offended the Pope. Furiously, Urban recalled Galileo to Rome to answer against charges of Heresy! This resulted in infamous trial of Galileo in 1633, in which he was forced to publically recant his beliefs, and sentenced to spend the rest of his life confined to house-arrest in the home of the archbishop of Siena. He continued to pursue science until his death at Arcetri, Florence in January 1641. Three centuries later, Galileo was officially ‘pardoned’ by Pope John Paul II.
  • 6. Conclusion: Nobody knows if Galileo really knew the long term implications of what his work with the telescope was going to achieve, what we do know is that he was driven by ambition and the need for fame as much as anything. Headstrong, egotistical and argumentative, “The Father Of Science” is hardly a shining example of the natural philosopher out to defend progress against the backwards ravages of religious intolerance, but this essentially is what he was. It was these qualities that he needed to overcome the fierce resistance his radical arguments faced, especially from such powerful foes as the Church, and it was his creative use of the telescope that proved Copernicus’ theory beyond any shadow of a doubt. If timid Copernicus was the one who started the ball moving in the Copernican Revolution, then it was audacious Galileo who took that ball and kicked it into the face of the old world system. Once truth had prevailed over belief in astronomy, the seeds where planted for the blossoming of science in Europe. If the scripture was wrong, what could the church rest on now? Decades later, Newton would formulate his first law of motion based on Galileo’s theory of inertia, and it’s hard for anyone to deny that the world would not be a different place if it had not been for Galileo Galilei. Bibliography Baumgardt, C. (1953). Johannes Kepler: Life and letters. Philosophical Library. (1993). Galileo, Courtier: The Practice of Science in the Culture of Absolutism. In M. Biagioli. Chicago University Press. Cropper, W. H. (2001). Great Physicists. New York: Oxford University Press. Galilei, G. (n.d.). Galileo Galilei, "Siderius Nuncius". Retrieved April 21, 2008, from Liberliber.it: http://www.liberliber.it/biblioteca/g/galilei/sidereus_nuncius/html/sidereus.htm Kesten, H. (1945). Copernicus and His World. (E. G. Aston, Trans.) New York: Roy Publishers. Machamer, P. (1998). The Cambridge Companion to Galileo. Cambridge University Press. Reston, J. (2000). Galileo: A Life. Beard Books.