THE MOTHER OF LOVE
When Galileo arrived in Florence on 12 September 1610, it was not to rest on his laurels but to resume immediately his early observations of the heavens. He was not disappointed for Venus so on sp ok e out. The “mother of love,” as poets called her, went through phases like the Moon. This was important because among the difficulties raised against Copernicus was the objection that Venus should have phases because it lies between the Sun and the Earth. Copernicus had replied that they were too inconspicuous to be seen by the naked eye, and Galileo was anxious to know whether his telescope would enable him to detect them. Venus is usually too close to the Sun to be observed, and it was only in the autumn of 1610 that Galileo was able to confirm that Copernicus had been right: Venus goes through a complete series of phases that vary considerably in size. At its greatest distance from the Earth, it is seen as a perfectly round disk, fully illuminated. As it moves toward the Earth it grows in apparent size until at quadrature (corresponding to the first and third quarter of the Moon) it is half illuminated. At its closest to the Earth, it becomes invisible (like the Moon when it is new). The phases of Venus showed that it did not go round the Earth. But what about the other planets? Even if they also orbited around the Sun, this did not necessarily mean that the Earth behaved likewise. The Danish astronomer, Tycho Brahe, had come up, years before, with a compromise system where the Earth remained at rest but all the planets revolved around the Sun while the Sun continued to go around the Earth. Hence the phases of Venus could be used by the followers of Tycho Brahe as well as by those of Copernicus.
On 17 December 1610, Galileo wrote to his former student, Benedetto Castelli, that those who were not convinced of the truth of Copernicanism, even before the discovery of the phases of Venus, were bookish philosophers who cared only for the empty applause of the vulgar crowd. This letter reveals a side of Galileo’s character that will recur in his private writings and before long in his published works. He was stung by reluctance or, worse, refusal to accept his discoveries, and he was becoming impatient, even arrogant, with people who criticized him. He hit back by exaggerating, as he did in this case by claiming that even before the phases of Venus had been observed there was convincing proof that Copernicus was right. To the end of his life, Galileo held to a simplified version of the Copernican system in which all the planets move in perfect circles. Although he preached open-mindedness, he never lent an ear to Kepler’s arguments about elliptical paths.
Well-meaning astronomers who did not have good telescopes experienced serious difficulties. On 22 January 1611 Christopher Grienberger, a Jesuit professor who was always to remain sympathetic to Galileo, wrote him a long letter in which he explained how his extensive experiments with mirrors had initially led him to query whether the lenses did not distort the shape of objects. His doubts were only dispelled when he was provided with a suitable instrument. As the telescopes improved, so did Galileo’s reputation, but the skeptics remained numerous, and this is why Galileo wanted to go to Rome.
SEEING AND BELIEVING
The Sidereus Nuncius had opened a lively debate over the reliability of the new instrument of observation. We can see this in the way two ambassadors had reacted. On the very day the booklet appeared, Sir Henry Wotton, the English ambassador to the Republic of Venice, sent a copy home to King James I, calling it “the strangest piece of news” that the king had “ever yet received from any part of the world.” He described the sensational news briefly and accurately and promised to send one of the new instruments by the next ship. Before concluding, however, Wotton realized that he might have been too sanguine and covered himself neatly against that risk by adding: “And the author runneth a fortune to be either exceeding famous or exceeding ridiculous.” Shortly thereafter, Georg Fugger, the imperial ambassador in Venice, wrote to Kepler, the imperial astronomer at Prague, then the centre of the Holy Roman Empire, that many thought the Sidereus Nuncius was just show, and that Galileo had copied a telescope brought by a Dutchman to Venice. Kepler knew better and his response was more than generous. By 19 April 1610, he had written Galileo a letter of endorsement, which he prepared for publication even if he had not yet had the use of a telescope. Giovanni Magini, the professor of mathematics at Bologna, was initially much cooler and told Kepler in May that he thought the discoveries were illusory. A wealthy scientific amateur and friend of the Jesuits, Mark Welser, was still vacillating in January 1611, as we know from a letter he wrote asking Clavius his opinion about Galileo’s observations. It was only after Clavius had assured him that they were reliable that he breathed a sigh of relief. If the Jesuits agreed with Galileo that was enough for him.
The Jesuits kept abreast of scientific progress but not every one in Florence was willing to be convinced by an optical tube. A philosopher named Ludovico delle Colombe circulated a manuscript treatise in which he not only ridiculed the motion of the Earth but fired the first theological broadside by claiming that it was at variance with the teaching of Scripture. Delle Colombe piled up scriptural quotations without regard to their context: “You fixed the earth on its foundations” (Psalm 104:5); “God made the orb immobile” (1 Chronicles 16:30); “He suspended the earth above nothingness, that is, above the centre” (Job 26:7); “Before the mountains were constituted with great weight” (Proverbs 8:25); “The heaviness of stone, the weight of sand” (Proverbs 27:3); “Heaven is up, the earth is down” (Proverbs 30:3); “The sun rises, and sets, and returns to its place, from which, reborn, it revolves through the meridian, and is curved toward the North” (Ecclesiastes 1:5); “God made two lights, i.e., a greater light and a smaller light, and the stars, to shine above the earth” (Genesis 1:17), this last quotation being offered as proof that the Moon can in no way be like the Earth.
Delle Colombe considered whether these passages could be interpreted in a non-literal sense: “Definitely not,” he decided, “because all theologians, without exception, declare that when Scripture can be understood literally, it ought never be interpreted differently.” The literal reading of Scripture and the consensus of the ancient Fathers were unqualified exegetical standards for delle Colombe. Rather than risk a reply, Galileo preferred going to Rome to have his discoveries authenticated. Once the Church had recognized them as real, all would be well!
THE EARLY ROMAN AGENDA
Galileo contacted Belisario Vinta toward the end of 1610 and explained why a trip to Rome was necessary. When he did not receive a formal authorization by 15 January 1611, he reminded Vinta that he was dutifully awaiting instructions from the grand duke and begged leave to say that this was the best time to act and publicize his discoveries. Vinta, who knew that Clavius and Kepler had already sanctioned Galileo’s claims, judged that the court risked nothing in allowing him to go. The trip could only heighten the stature of Galileo’s patron, the grand duke, whose brother Carlo currently filled the traditional position of resident Medici cardinal in Rome.
Once the trip was approved, Galileo might have been expected to leave forthwith, but he was so indisposed and had such headaches that he postponed his departure for another two months while he recuperated at Salviati’s villa. Nonetheless he did not neglect his correspondence and, on 12 February 1611, wrote to his old friend Paolo Sarpi in Venice to say that he was busy replying to his detractors but that the best European mathematicians, including those who had first laughed at him, were now entirely on his side.
At the end of February, the journey seemed imminent, and the grand duke wrote to Giovanni Niccolini, his ambassador in Rome, in terms that leave no doubt that he wanted Galileo to be treated as an official envoy:
Our beloved Mathematician and Philosopher, Galileo Galilei, is going to Rome, and we have decided that he should stay with you in our palace there. It is our wish that you should make him welcome and take care of his expenses and those of one servant. Make a note of these in order to be reimbursed. You will be glad to see him and you will appreciate his intelligence and pleasantness. He will tell y
ou himself why he is making the trip, and you will help him in every way possible, as he requests and as you see fit, more particularly with the advice of Cardinal del Monte for whom we have given him a letter of recommendation. The business that he will undertake is close to our heart both for its usefulness to the world of learning and the glory of our house. May God keep you and bless you.
But still Galileo did not leave. On 5 March 1611 he informed Clavius that his departure had been delayed because of his poor health and the appalling weather but that he hoped to set out within a week. Meanwhile, tributes to his achievements began to pour in. From Padua, the great humanist and archaeologist Lorenzo Pignoria wrote to say that Galileo’s celestial discoveries would eclipse those of Columbus and Vespucci. The duke of Zbaraz informed him that his fame had reached Moscow, adding, for good measure, that his discoveries would ensure that their century would always be remembered.
Summoning all his energy, Galileo decided it was time to make a move and suddenly gave way to impatience. On 19 March he wrote to Belisario Vinta to say that he was eagerly awaiting the horse-drawn litter that would carry him to Rome, where he wanted to arrive by Holy Week “in order to put an end, once and for all, to malignant rumors.” He added that he expected a prompt reply “unless the Grand Duke has changed his mind,” a qualification that could suggest that he was still of two minds about setting forth. Vinta replied that the court had gone to Livorno, but he had had a word with the grand duchess and a litter was on its way. Galileo did not depart immediately, however, but took a little extra time to obtain a letter of recommendation from Michelangelo Buonarroti (the nephew of the famous artist whose name he carried) for Cardinal Maffeo Barberini, who would become pope as Urban VIII 12 years later and was to preside over the Galileo Affair. The weather finally cleared up and Galileo set out on 23 March. He spent six days on the road in the grand duke’s litter, and at night he set up his telescope at every stop along the way—San Casciano, Siena, San Quirico, Acquapendente, Viterbo, and Monterosi—to continue to track the revolutions of Jupiter’s moons. This shows how dedicated he was to his work in spite of indifferent health and the cold and dampness of March evenings.
ROMAN HOLIDAY
Galileo was the honored guest of the grand duke in Rome. But where? The Medici owned several palaces in Rome. From the letter of Cosimo II it seems that the residence of the Tuscan ambassador was intended, and this has frequently been assumed to be the Villa Medici on the Pincio. The embassy, however, was not located there but in the Palazzo Firenze near the Pantheon. This is confirmed by a letter from Galileo to Belisario Vinta at the time when the ambassador, Giovanni Niccolini, was about to retire later in May. In order not to inconvenience the new ambassador, Piero Guicciardini, Galileo offered to leave the embassy and take up residence in the Villa Medici. Guicciardini declined and Galileo remained as his house guest in the Palazzo Firenze.
Giovanni Niccolini, who was nearing the end of a distinguished 23-year career as Tuscan ambassador, welcomed Galileo when he arrived on 29 March, which was Holy Tuesday that year. On the very next day he reported to the grand duke that Galileo had arrived safely with two servants (instead of one as authorized) and that lodgings had been provided for all of them.
Galileo lost no time and sprung into action on the very day he arrived by calling on Cardinal del Monte. Three days later, on Good Friday, he commented on the warmth of the Roman welcome:
I arrived in good health on Holy Tuesday and I handed over the letter of the Grand Duke to the Ambassador, who welcomed me very courteously and with whom I am staying. On the very same day, I called on Cardinal del Monte to whom I gave the other letter from the Grand Duke, and I told him briefly about the purpose of my trip. The Cardinal received me very courteously and listened attentively to what I had to say before expressing the firm hope that I would not leave without having been able to give a full and satisfactory account of the complete truth of what I have discovered, observed and written.
The next day, 30 March, Galileo went to the Roman College to meet Clavius and his younger colleagues, Christopher Grienberger and Odo Maelcote, who carried out telescopic observations for Clavius, who was now well into his seventies. “I found that these Fathers,” wrote Galileo to Vinta,
have finally recognized the genuineness of the Medicean planets, and continue the regular observations that they began two months ago. We compared them with my own and they agree entirely. They also are working hard to find their periods of revolution but they agree with the Mathematician of the Emperor [Kepler] that it will be very difficult and almost impossible. I hope, however, to discover and determine them, and I trust that God Almighty, who made me the grace of discovering so many new marvels from his hand, will grant me to find the exact period of their revolutions. Perhaps, by the time I return, I shall have achieved this and be in a position to determine the places and positions that these new planets will have at any time in the future or that they occupied in the past, provided I have the strength to continue my observations late into the night, as I have done until now.
Galileo may not have been a conventionally devout Catholic, but he was deeply convinced that God had singled him out to make not only some but all the new celestial discoveries. He treated the contributions of other astronomers as inferior to his own. This was deplorable, and it led a malicious but perceptive critic to accuse him, when he returned to Florence, of trying to add a terrestrial empire to the one he had already claimed in the heavens. Galileo may have had an excessive conceit of himself, but he was head and shoulders above his rivals. The grand duke could rightly be proud of his scientific envoy.
On 2 April, the eve of Easter, Galileo went to Cardinal Maffeo Barberini’s residence to present the letter of recommendation from Michelangelo Buonarroti, as well as another written by Antonio de’ Medici. No sooner had Galileo left than the Cardinal wrote to both Buonarroti and Antonio de’ Medici to say that he would be delighted to help Galileo in any way in his power. The Rome sojourn could not have begun under better auspices: High-ranking prelates lionized him and famous professors treated him as the leading authority in his field.
The Counter Reformation did not curtail the Roman passion for public and private festivities. Gatherings where artists showed their work and writers read their latest poems were frequent and well attended. Particularly successful was the informal academy of Giovanni Battista Deti, the nephew of Pope Clement III, who had appointed him cardinal in 1599, when he was only 17 years old. In the week of Easter, Galileo was invited to one of Deti’s meetings, where he met four cardinals, as well as numerous prelates and other dignitaries. Galileo informed a Florentine correspondent that he had enjoyed the learned talk given by Giovanni Battista Strozzi but that he did not join in the discussion for fear of appearing too pushy since this was the first time he had been invited. He assured his correspondent that he would not be deterred by such considerations in the future. The topic was pride.
STARGAZERS
In less than a week, Galileo had called on cardinals Barberini and Del Monte, greeted several other prelates at the Academy of Deti, and spoken to the Jesuits. He had also paid a courtesy call on Cardinal Ottavio Bandini, who belonged to a prominent Florentine family and to whom Galileo had been recommended. Bandini had a house next to the residence of the pope on the Quirinal, and he asked Galileo to organize telescopic observations in his garden for members of the Roman high society.
Galileo also displayed his instrument elsewhere, often in the setting of an evening meal and to the accompaniment of music. One such banquet, at which he was the guest of honor, was to have lasting consequences for his work. It was organized by an idealistic young nobleman, Federico Cesi, Marquis of Monticelli. In 1603, at the age of 18, Cesi had founded with three friends the Accademia dei Lincei (Academy of the Lynxes or Lyncean Academy), which had the notable feature that its members were not to confine themselves to literature or the arts but were to give pride of place to the study of nature and mathematics. The choic
e of the sharp-eyed lynx as an emblem stressed the importance Cesi attached to faithful observation of nature, and at official ceremonies he often wore a lynx pendant on a gold chain. Until 1610, when he became financially independent, Cesi had been able to do little, but he was now eager to pool his wealth, curiosity, and foresight into a cooperative endeavor, free from traditional academic constraints. He had a keen sense that Galileo had opened a new field of investigation. At the dinner party that Cesi arranged on Thursday 14 April to honor Galileo, the telescope was used in broad daylight before the meal to look at buildings in the city, and after the meal, when it became dark, at the night sky.
A first-rate metteur en scène, Cesi had not neglected to inform the press, and a couple of days later Romans could read in the Avvisi (a forerunner of the gossip columns of our daily newspapers) that the mathematician Galileo Galilei, “whom the Grand Duke had appointed professor at Pisa with a salary of one thousand scudi,” had arrived in Rome. Then, as now, the press assumed that a high salary indicated scientific excellence. Informed about Galileo’s high status, the reader was well disposed to accept that he had found four satellites around Jupiter. The account added that he had recently discussed this discovery with Clavius, a clever way of conveying the impression that the Jesuits backed his claims.
Shea and Artigas - Galileo in Rome Page 4