The truth about the Galileo affair
Despite the considerable evidence that the Bible provided the necessary intellectual basis for science,1 atheists often claim that, historically, science and religion have been at war. For centuries, they say, the church opposed the advancement of science and human progress in general. When asked for evidence in support of this view, they usually cite the ‘Galileo affair’. Few, however, know what really happened, and many historians see the events of the time very differently to the caricatures often presented by the media.
Galileo Galilei (1564–1642) was one of the giants of early science. Although best-known for his work in astronomy, he was also an accomplished mathematician and made significant contributions to the understanding of motion, materials, and the development of the scientific method. Some have even described him as the ‘father of science’.
During the seventeenth century, there was much debate about the motions of the heavenly bodies and whether or not the earth was the centre of the universe. Galileo believed that the earth moved around the sun and argued against the popular view that the sun moved around the earth. In 1633, the Roman Catholic Church forced him to renounce this view as heresy and imprisoned him for writing a play in which he argued in favour of it. Consequently, Galileo has often been portrayed as a martyr to progress, someone who was shamefully persecuted by an ignorant clergy simply because he attempted to further the advancement of science.
The reality, however, is quite different. At the time of Galileo’s trial, the scientific evidence did not support his assertion that the earth moves, and his ‘proof’ that it did was based on a flawed argument. It was only many years later that scientists were able to confirm that he was right.2 Galileo was foolish and arrogant in the way he argued his case; he made enemies unnecessarily and threatened the establishment’s hold on the education system. Even at the time, many considered that he was the victim of politics rather than attempts to safeguard Christian doctrine.
Our solar system
Our solar system comprises a sun and a number of planets, together with moons, asteroids (rocky bodies) and a few comets. How all this is arranged, and how these different heavenly bodies move in relation to the earth has, historically, been the subject of much debate.
The teaching of the ancient Greeks led to the widespread belief that the earth is static (i.e. stationary) and that everything else rotates around it. (See fig. 1.) This is known as the ‘geostatic and geocentric’ model—from Greek, gē (the earth), statikos (causing to stand) and kentron (centre). Aristotle held that the heavenly bodies were perfect spheres, unblemished and unchangeable, and moved in perfect circles. The earth, known at the time to be a sphere, was believed to be positioned at the centre of the universe and provided the only centre of rotation. For many years, this was held to be the ‘scientific view’.
A few hundred years later, Egyptian astronomer Claudius Ptolemy (c. 100–170 AD) realised that the planets’ orbits could not be simple circles. To make the geocentric model fit with observations of the planets’ actual paths, he included additional movements, known as ‘epicyles’—from Greek, epi (upon) and kyklos (circle). These were detours from a perfect circle whereby the planets circled on circles. (See fig. 2.) Ptolemy’s system was explained in his famous book, the Syntaxis (Greek) or Almagest (Arabic), and became the ruling astronomical paradigm for over a millennium.
Another model was proposed by Nicolaus Copernicus (1473–1543) which put the sun at the centre, with the planets, including the earth, in orbit around it. (See fig. 3.) This is known as a ‘heliocentric and geokinetic model’—from Greek, hēlios (the sun) and kentron (centre); and, gē (the earth) and kinētikos (moving). Here, as well as orbiting the sun once per year, the earth spins, completing a full rotation every 24 hours. Copernicus argued that the spinning of the earth explains the apparent movements of the sun (and other heavenly bodies) around the earth over the course of the day and night. As with Ptolemy’s model, the planets’ orbital paths were circular but with added epicycles. Again, these were needed to make the theory fit with observations. This heliocentric model was favoured by some mathematicians as a means of predicting the positions of the planets over time. In 1533, the Copernican theory was presented to Pope Clement VII who received it favourably and rewarded the presenter with a generous gift.3
Another model was proposed by Danish astronomer Tycho Brahe (1546–1601). As with the Ptolemaic system, the earth was stationary and central, with the sun, moon, and stars in orbit around it. However, the planets orbited the sun. (See fig. 4.) By the end of the sixteenth century, Brahe’s system had largely replaced Ptolemy’s as the preferred model.
Yet another model was suggested by Johannes Kepler (1571–1630). This was similar to the Copernican system, having the earth and other planets in orbit around the sun. However, Kepler eliminated the need for epicycles by having the planets moving in elliptical orbits with the sun at one focus (not the centre) of the ellipse. This was by far the simplest and neatest theory. Again, the earth spins.
It wasn’t until Isaac Newton (1643–1727) that the matter could be settled. Newton’s law of gravity and his three laws of motion made clear that the planets (including the earth) had to orbit the solar system’s centre of mass. Because the sun is so massive the centre of mass can be treated as being at the sun’s centre. Kepler’s model, then, was proven to be the correct one—there was neither need for nor a physical mechanism to produce epicycles.
Heliocentrism and the Bible
Some have argued that models requiring a moving earth must be wrong because the Bible teaches that it is stationary. For example, Psalm 96 reads:
“Say among the nations, “The Lord reigns! Yes, the world is established; it shall never be moved; he will judge the peoples with equity.” (Psalm 96:10).
Similarly, Psalm 104 says of God:
“He set the earth on its foundations, so that it should never be moved.” (Psalm 104:5).
Others respond that there is no need to interpret such verses in this way. In Psalm 96:10, the context relates to God’s reign over humanity, not the physical condition of the earth. Also, the Hebrew word translated ‘moved’ in Psalm 96 is also used in Psalm 16 (where it is translated ‘shaken’):
“I have set the Lord always before me; because he is at my right hand, I shall not be shaken.” (Psalm 16:8).
Clearly the Bible is not teaching here that those who keep their eyes on God will never move in a physical sense.
In Psalm 104, the language, generally, is poetic rather than literal. For example, it states that “The Lord wraps himself in light as with a garment” and “He makes the clouds his chariot”. Hence the context indicates that there is no need to understand verse 5 as scientific statement describing the physical condition of the earth.
Some have argued that the Bible teaches that the sun cannot be stationary. The book of Ecclesiastes and the book of Joshua, they say, clearly teach that the sun moves:
“The sun rises, and the sun goes down, and hastens to the place where it rises” (Ecclesiastes 1:5).
“At that time Joshua spoke to the Lord in the day when the Lord gave the Amorites over to the sons of Israel, and he said in the sight of Israel, ‘Sun, stand still at Gibeon, and moon, in the Valley of Aijalon.’ And the sun stood still, and the moon stopped, until the nation took vengeance on their enemies. Is this not written in the Book of Jashar? The sun stopped in the midst of heaven and did not hurry to set for about a whole day” (Joshua 10:12–13).
Others argue that there is, again, no conflict here between the Bible and science. They say that, in these passages, the Bible is using the ‘language of appearance’ (phenomenological language), just as scientists do today when they speak of ‘sunrise’ and ‘sunset’. Alternatively, this language acknowledges that all motion must be described with respect to a reference frame; in this case, they are choosing the earth. In fact, even before Christ, there was a line in the Aeneid, the famous epic by Virgil (70–19 BC), where a moving boat was used as a reference point. Virgil wrote, “We set out from harbour, and lands and cities recede” (Aeneid 3:72). Similarly, when a train arrives at a station, we say that it stops to allow the passengers to get on and off; but once again, this treats the earth as a reference frame. The earth is flying through space at thousands of km/h in order to orbit the sun once per year, and the train is carried along with it. Hence, from the reference frame of an observer outside the solar system, it is always moving. However, most people would agree that to say that the train stopped is perfectly reasonable. Similarly, creation scientists argue that it is reasonable for the Bible to say that the sun stopped as, from the reference frame of the earth, this is how it appeared.
It took many years for astronomers to become sure of the heliocentric/geokinetic model, and one scientist who contributed to this process was Galileo. In 1609, he built a telescope which enabled him to study the heavenly bodies in far greater detail than had been possible previously. Some of his observations provided growing evidence that Aristotle’s teaching was wrong. For example, Galileo was able to see that the moon’s surface was uneven, having craters and mountains. It was, therefore, not a perfect shape as Aristotle maintained. It also became apparent that Jupiter had moons in orbit around it, demonstrating that the earth was not the only centre of rotation. Sunspots (fig. 6) were seen to come and go, demonstrating that the heavenly bodies were not unchangeable. People naturally began to ask: If Aristotle was wrong about these matters, could he not also have been wrong in teaching a geocentric universe?
Another important discovery was that, like the moon, Venus has phases; that is, it waxes and wanes, changing from a thin crescent to almost a full circle. Galileo realised that the way Venus’s appearance changes is inconsistent with geocentric models, but consistent with heliocentric models (see figs 7 and 8.) Aristotle and Ptolemy, then, appeared to be wrong.
Galileo became convinced that Copernicus was correct and argued that we could be sure that the earth was in motion because of the oceanic tides. The spinning of the earth, he said, along with its orbiting of the sun, caused the water to ebb and flow over the earth’s surface. We now know, of course, that this is wrong. The tides occur due to gravitational effects arising from the moon. Actually, back in the 8th century, ‘the Venerable’ Bede had correctly linked the tides with the moon.
While some Roman Catholic astronomers were favourable to the Copernican system, others, including some of the leading scientists of the day, felt that Galileo’s insistence on the ‘fact’ of the Copernican system went well beyond the evidence. If the earth spun, they asked, why didn’t everything fly off it, as water flies off the rim of a spinning wheel? Also, why were there not fierce winds? A pressing problem with heliocentric models was that they predicted that small changes in the positions of stars would be visible over the course of the year. This is known as ‘stellar parallax’ and is illustrated in fig. 9.
Although this does occur, and is observed today, astronomers at the time were unable to see it due to their instruments being too weak. Moreover, the phases of Venus could also be explained by Tycho Brahe’s model, so they did not provide proof of the Copernican model at all. Cristoforo Grienberger, one of the Church’s most respected astronomers, argued that Galileo would do better to produce more convincing proofs before seeking to ‘adjust’ Scripture to fit with his theory.4 Indeed, for many, the failure to observe changes in the positions of the stars strongly favoured Brahe’s model.5
A bad start
Cardinal Robert Bellarmine was arguably the most respected Roman Catholic theologian of the time, and was also knowledgeable about astronomy. His view was that the Bible probably did teach that the sun orbits the earth; but, in a letter written in 1615, he acknowledged that, if it could be demonstrated that the earth orbits the sun, it would be necessary to reconsider how the scriptures should be interpreted in this matter. However, he also made clear that no such demonstration had been given to him. He wrote:
“… if there were a real proof that the sun is in the centre of the universe … and that the sun does not go round the earth but the earth round the sun, then we should have to proceed with great circumspection in explaining the passages of Scripture which appear to teach the contrary, and we should rather have to say that we did not understand them … But I do not think there is any such proof since none has been shown to me.”6
Galileo had not presented this proof because he didn’t have it. Instead, he bluffed, ridiculed his opponents and, in remarkable arrogance, claimed that the problem lay in their inability to follow his arguments.7 He became impatient and, early in 1616, sought to convince the pope (that is Pope Paul V), presenting the oceanic tides as ‘proof’ that the earth is not stationary. The pope responded by summoning his advisors8 whom he asked to consider the matter. Under pressure to provide an answer, they responded quickly. Their conclusion was that Galileo’s belief that the sun is stationary was contrary to Scripture and heretical, and that his view that the earth is not stationary was an error.
In response, the pope directed that Cardinal Bellarmine urge Galileo to abandon his opinion and, if he refused, be commanded before witnesses, under threat of imprisonment, to refrain from teaching, defending, or even discussing it. Galileo agreed to abide by the ruling. In addition, on 5 March 1616, it was decreed9 that Copernicus’s theory was “false and contrary to Holy Scripture”. The decree, however, stopped short of condemning it as heretical. Moreover, Copernicus’s book was not to be “prohibited and condemned”, because it was felt that, with amendment, it would present the heliocentric theory only as a ‘mathematical hypothesis’, rather than something true and reconcilable with Scripture. Indeed, as a means of performing calculations, and producing calendars and star charts, it was considered useful. Hence, it was only to be “suspended until corrected”.
Although approved by the pope, these rulings were not endorsed in such a way as to make them unchangeable—and deliberately so.10,11,12 Hence, the pronouncement against the Copernican system could, in theory, be reversed at some point in the future. Moreover, the requirement for Galileo to “abandon his opinion” should be understood in the context of a written statement, by Cardinal Bellarmine himself, to the effect that Galileo had not been forced to renounce his view.13,14 Although Roman Catholic astronomers were required to conform outwardly, there was no absolute prohibition on their inward thoughts on the matter.15 Nor were they prohibited from discussing it quietly among themselves.16
Some have maintained that the Roman Catholic Church’s ruling on this matter was based primarily on religious considerations. Others, however, doubt this. For many academics of the day, the suggestion that the earth was not stationary seemed a radical and even dangerous idea, a departure from common sense and the perceived wisdom held almost universally by the esteemed scholars of the past. And as pointed out above, it conflicted some of the best science of their day. It threatened to overthrow the very foundations of medieval astronomy and discredit Aristotle, the revered philosopher whose writings had been the basis of what had been taught in the universities for centuries. According to Professor Giorgio de Santillana, it was chiefly these professors, rather than churchmen, who were behind the prohibition of Copernicanism in 1616.17
A second chance
In 1623, a friend of Galileo became pope—Pope Urban VIII. Urban had supported Galileo in 1616 and had opposed the view that his teaching was heretical. Had it been in Urban’s power, the prohibition against the Copernican theory would not have been passed.18 Moreover, as pope, he had confided to a colleague that, in his understanding, the church had neither condemned nor would condemn the doctrine of Copernicus as heretical, but only “rash”.19 Hence, he was happy for Galileo to argue in favour of the model, so long as he presented it only as a hypothesis—albeit one that explained the observations very well. He could not, however, assert that it was true, as God, he said, being all-powerful, could have produced the observable effects in some other way.
Greatly encouraged, Galileo set about writing a play20 in which the arguments for and against the geocentric and heliocentric systems were to be discussed. As a literary work, it was brilliant—witty, majestic, and composed of breath-taking language. As a scientific treatise, however, it fell far short of what might be expected from a man of Galileo’s abilities.21 For example:
- It misrepresented the Copernican model making it appear much simpler than it is. With its need for epicycles, Copernicus’s model was arguably as complicated as Ptolemy’s.
- It failed to give due consideration to Tycho Brahe’s model, the one favoured by many astronomers of the day.
- It argued that the tides arose due to the motion of the earth and failed to engage seriously with the alternative view that they were the result of the influence of the moon.
According to Albert Einstein, had Galileo not been so passionate in his quest to convince people of the Copernican model, and had someone else presented the tides as evidence for the earth’s motion, Galileo himself would have been among the chief sceptics. Einstein wrote:
“It was Galileo’s longing for a mechanical proof of the motion of the earth which misled him into formulating a wrong theory of the tides. The fascinating arguments in the last conversation [in the play] would hardly have been accepted as proofs by Galileo, had his temperament not got the better of him.”22
The play was finished in 1630 and printing was completed in 1632. It did not, however, present the Copernican system as just a hypothesis, and was soon to incur the wrath of Galileo’s enemies. Many in the church hierarchy were devoted Aristotelians, having embraced much of his philosophy and ‘science’. They believed that they had ‘Christianised’ his formidable logic and now used it in defence of the Roman Catholic faith, and as the basis for teaching in their universities. To discredit Aristotle was to discredit them, compromise their authority and threaten their hold on the education system. Yet, over the previous thirty years, this was exactly what Galileo had done. He had refuted Aristotle’s teaching on a number of issues relating to motion and the behaviour of bodies in water. He had demonstrated that the heavens are not unchangeable, that the heavenly bodies are not perfect, and that the earth is not the centre of all heavenly motions (e.g. the moons of Jupiter). Now he was arguing that the earth is not stationary. Moreover, in Galileo’s play, Aristotelians were ridiculed, and their defender portrayed as a simpleton named “Simplicio”. Those who did not share the Copernican view were described as “mental pygmies”, “dumb idiots” and “hardly deserving to be called human beings”.23
This kind of folly and arrogance was not untypical of Galileo. In a private note he wrote of himself that “it was granted to me alone to discover all the new phenomena in the sky and nothing to anybody else. This is the truth which neither malice nor envy can suppress.” Similarly, in his play, he claimed to be the original discoverer of the solar spots and “all other novelties in the skies”.24 Arthur Koestler wrote of Galileo’s approach to debate:
“His method was to make a laughing stock of his opponent in which he invariably succeeded, whether he happened to be in the right or in the wrong. … It was an excellent method to score a moment’s triumph, and make a lifelong enemy.”25
For the Aristotelian professors, Galileo’s play was the last straw, and they united against him. They pointed out to the pope that his favourite argument—that Copernicanism could not be proven because God could produce the observed effects by numerous different means—had been put into the mouth of Simplicio, the man who, on every other point, had been proved wrong. Moreover, they persuaded him that Simplicio had been intended to be a caricature of his own person. The pope, a proud and vain man, was enraged, not only by this, but because he felt betrayed by Galileo’s failure to abide by his instruction that the play should present the Copernican model only as a hypothesis. Feeling that he had been deceived, the pope ordered that Galileo be brought to trial by the Inquisition.
In 1616, Cardinal Bellarmine had been instructed to warn Galileo to abandon the Copernican theory and, if he refused, be commanded before witnesses, under threat of imprisonment, to refrain from teaching, defending, or even discussing it. A church document, dated 3 March 1616, records that Galileo acquiesced, suggesting that he was never actually prohibited from discussing it.26 Cardinal Bellarmine’s note (see above), testifying that Galileo had not been forced to renounce his view, would seem to support this interpretation. However, at the trial, another document was produced indicating that the prohibition not even to discuss it had actually been given. This stated that Galileo had been commanded not “to hold, teach or defend it in any way whatsoever, verbally or in writing.” The validity of this latter document, however, has been the subject of much discussion. The usual signatures are missing and the witnesses were servants who had no knowledge of the procedures.27 While some historians think that the document was genuine,28 others have suggested that it was a deliberate forgery by Galileo’s enemies;29 still others believe that the record had simply been written in error.30 Galileo himself denied all knowledge of this prohibition.31,32
Despite its questionable nature, the document stating that Galileo had been commanded not to defend Copernicanism “in any way whatsoever” was accepted by the Inquisition. Moreover, it was asserted that the heliocentric view was contrary to Scripture and heretical. Galileo, they concluded, had disobeyed the command not even to discuss the Copernican theory, and had rendered himself “suspected of heresy”. In order to avoid further charges, Galileo was forced on oath to renounce the heliocentric view as heretical and false. In addition, he was sentenced to imprisonment, albeit an ‘incarceration’ which was merciful by any standard. Firstly, he was confined in the Grand Duke’s villa and secondly in a palace in Sienna where he worked “in an apartment covered in silk and mostly richly furnished”.33 Thereafter he remained under house arrest until his death.
Many at the time questioned the justice of the verdict and sentence. The view that the heliocentric theory was heretical was not one that was held universally within the church. Cardinals Bellarmarine and Conti, for example, had both agreed that Scripture might legitimately be interpreted differently, allowing for a moving Earth.6,34 One archbishop is on record as stating that “Galileo was the greatest man of the age, that his condemnation was unjust, [and] that the Inquisition should not have ruled on a question of science”.35 Even the pope himself had previously described Copernicus’s theory only as “rash”. According to Professor Klaus Fischer, “That the whole trial was questionable could not be hidden to insiders. There was much resistance by high Church officials”.36 Moreover, by the end of the century, the Copernican theory was being freely taught by Roman Catholic astronomers.37
At the time of Galileo’s trial, the scientific evidence favoured a geostatic model. This was because, due to the imprecision of their instruments, astronomers were unable to observe the stellar parallax predicted by geokinetic models. The phases of Venus, however, indicated that Ptolemy’s model was wrong. Hence, Brahe’s geostatic (but partly heliocentric) model was thought by many to be the correct one. It was only years later that Newton’s laws of motion and gravity finally established Kepler’s geokinetic/heliocentric model as being correct.
Galileo was wrong in asserting that the Copernican system was correct. Although the planets do orbit the sun, they do not move in circles with epicycles; rather their orbits are ellipses. Although Galileo was right in arguing that the earth is in motion, his primary ‘proof’ was wrong. The tides do not arise due to the earth’s motion, and Galileo’s contemporaries rightly questioned this. The Roman Catholic Church at the time had every reason to doubt Galileo’s assertions, and the pope had every reason to insist that Galileo present Copernicus’s theory only as a hypothesis.
Galileo lacked humility and was foolish in the way he argued his case. He made claims that he could not substantiate and mocked those who held different views. He did not co-operate with other scientists such as Kepler, and failed to learn from them. He antagonised his opponents and invited their hostility.
For many years, Galileo had been demonstrating that Aristotle’s ‘science’ was wrong. Since much of the teaching in the universities was based on Aristotle’s writings, the academics of the time felt threatened. Galileo’s method in debate was to deliberately humiliate his opponents, making them appear foolish. Consequently, he made many powerful enemies.
Galileo’s opponents misused Scripture to attack him. The Bible is not a science text book. It gives an account of what happened in history but does not explain how it happened. From the reference frame of people on Earth, the sun does rise and set, and it is appropriate for the Bible to use this kind of language in describing its motion—just as scientists do today. However, the Bible does not provide scientific details of the process which causes this effect.
It was a mistake for Galileo’s opponents, based on their ‘Aristotelian science’, to insist on a geocentric interpretation of Bible passages like Psalm 96:10 and Ecclesiastes 1:5. Indeed, for those who regard the Bible to be the Word of God, it would seem unwise to use any science to force a particular interpretation of Scripture because science is the thinking of fallible men. Moreover, it would seem remarkable that some in the Roman Catholic Church should hold the teaching of ancient Greek philosophers in such high esteem when so much of this clearly contradicts the Bible.
Galileo’s trial is not an example of religion opposing science. According to Professor Santillana, “… a major part of the Church intellectuals were on the side of Galileo, while the clearest opposition to him came from secular ideas.”38 Rather, it is a sorry tale of human pride and the protection of self-interest. As argued by Professor Thomas Schirrmacher, “Galileo was the victim of his own arrogance, the envy of his colleagues and the politics of Pope Urban VIII.”39 Indeed, the extent to which the affair was motivated by political rather than religious concerns is made clear by a statement by Grienberger, one of the leading church astronomers of the time. Had Galileo behaved reasonably, he said,
“he would have stood in renown before the world, he would have been spared all his misfortunes and he could have written what he pleased about everything, even about the motion of the earth.”40
References and notes
- Statham, D.R., Christian theology and the rise of Newtonian science: imposed law and the divine will, J. Creation 32(2):103–109, 2018. Return to text.
- Graney, C.M., Setting Aside All Authority: Giovanni Battista Riccioli and the science against Copernicus in the Age of Galileo, University of Notre Dame Press, 2015. See also review by Hartnett, J.G., J. Creation 32(1):45–47, 2018. Return to text.
- Rosen, E., Was Copernicus’ Revolutions approved by the Pope? J. History of Ideas 36(3):531–542, 1975. Return to text.
- Langford, J.J., Galileo, Science and the Church, 3rd Edn, University of Michigan Press, USA, p. 91, 1992. Return to text.
- Copernicus pointed out that, if the stars were very great distances from the earth, stellar parallax would be too small to observe. Furthermore, if stars were really as far away as needed by the Copernican model, then, as Brahe and his supporters pointed out, they would need to be unimaginably huge given their measured angular size. But in reality, this size is an illusion caused by diffraction, which produces a bright central pattern called the Airy disk (after Sir George Biddell Airy (1801–1892)). In reality, large modern telescopes show that images of almost all the stars are points, consistent with the huge distances, but this wasn’t known until centuries after Galileo. Return to text.
- Koestler, A., The Sleepwalkers: A history of man’s changing view of the universe, Penguin Books, pp. 454–455, 1984, first published by Hutchinson, 1959. Return to text.
- Ref. 6, pp. 456, 458–459. Return to text.
- That is, the Sacred Congregation of the Holy Office, a group of cardinals appointed by the pope as his advisors. Return to text.
- That is, by the Congregation of the Index, whose task was to censor (or ban) books which advocated teaching that was considered contrary to the Roman Catholic faith. Return to text.
- Ref. 6, p. 463. Return to text.
- That is, they were made in forma communi rather than in forma specifica. Only the latter carries the full weight of a papal act. See Bretzke, J.T., Consecrated Phrases: A Latin theological dictionary, 3rd Edn, Liturgical Press, USA, 2013. Return to text.
- Ref. 2, pp. 99–102. Return to text.
- Le opere di Galileo Galilei, vol. XIX, National edition, Florence, p. 348, 1907; archive.org. Return to text.
- For a translation, see ref. 4, pp. 102–103. Return to text.
- Journet, C., The Church and the Word Incarnate: An essay in speculative theology, vol. 1, Sheed and Ward, ch. VI, p. 357, 1955; ewtn.com. Return to text.
- De Santillana, G., The Crime of Galileo, Heinemann Group, UK, p. 233, 1961, first published 1955. Return to text.
- De Santillana, G., The Wilkins Lecture, 1964: Galileo Today, Proceedings of the Royal Society of London, Series A, Mathematical and Physical Sciences 280(1383):447–458 (p. 449), 11 August 1964. Return to text.
- Ref. 16, p. 183. Return to text.
- Ref. 16, pp. 162–163. Return to text.
- This was titled, Dialogue Concerning the Two Chief World Systems. Return to text.
- Ref. 6, pp. 483–484. Return to text.
- Dialogue Concerning the Two Chief World Systems—Ptolemaic & Copernican, translated by Stillman Drake, 2nd Edn, University of California Press, USA, foreword, p. xvii, 1967. Return to text.
- Ref. 6, p. 493. Return to text.
- Feingold, M., The grounds for conflict: Grienberger, Grassi, Galileo, and prosperity, in: Feingold, M., Edn, The New Science and Jesuit Science: Seventeenth century perspectives, Klewer Academic Publishers, USA, p. 139, 2003. Return to text.
- Ref. 6, pp. 458–459. Return to text.
- Ref. 6, p. 469. Return to text.
- Ref. 16, pp. 125–136. Return to text.
- Wootton, D., Galileo: Watcher of the skies, Yale University Press, UK, p. 152–153, 2010. Return to text.
- Ref. 17, p. 452. Return to text.
- Ref. 4, p. 97. Return to text.
- Ref. 28, p. 220. Return to text.
- Ref. 4, pp. 146–147. Return to text.
- Ref. 6, p. 500. Return to text.
- Ref. 6, p. 438. Return to text.
- Ref. 28, p. 225. Return to text.
- Fischer, K., Galileo Galilei, Munich, p. 126, 1983. Return to text.
- Ref. 6, p. 503. Return to text.
- Ref. 16, p. xii. Return to text.
- Schirrmacher, T., The Galileo affair: history or heroic hagiography? J. Creation 14(1):91–100, April 2000; creation.com/the-galileo-affair-history-or-heroic-hagiography. Return to text.
- Ref. 16, p. 290. Return to text.