Galileo Galilei

1. Galileo Galilei Or: How a telescope can get you into trouble This logo denotes A102 appropriate

2. In Context: • These changes, Copernicus through Galileo, all occurred during the Renaissance • Roots in the 13th century Florence with Dante (The Inferno) and Petrarch (humanist philosophy) • Composers 15th century Ockeghem and 16th century Gesualdo • Artists Bruegel the Elder, Raphael, and Michelangelo • And the Renaissance man, Leonardo da Vinci

3. Compare Bayeux Tapestry 11th C Pieter Breugel 16th C

4. Compare Regina Celi (plainchant) Stabat Mater (motet)

5. Rebirth • A rediscovery (and reinterpretation) of classical Greek and Roman times • A time of religious turmoil and growing humanism • Rise of merchant class, challenges to feudal system, urbanization, political change, roots of modern countries • Time of discovery, global expansion of Western powers • Copernicus, Brahe, Kepler all products of this rebirth

6. Another Field of Discovery

7. Into this Melee comes Galileo • B. 1564 in Pisa, son of famous musician, • Florentine Camerata • 1581 Enrolls in the University of Pisa • First in medicine, then switches to mathematics • Takes a teaching post at Pisa in 1589 • Moves to Padua to accept position of Professor of Mathematics in 1592

8. Even though a Devout Catholic… • Galileo fathered three children out of wedlock with Maria Gamba • The girls are forced to join a nunnery • Livia lives a quiet nun’s life • Vincenzio legitimized, becomes government worker • Virginia becomes Maria Celeste, remains close to her father and corresponds often (120 letters!)

9. * She will die at age 34 • Most Illustrious Lord Father,I cannot rest any longer without news, both for the infinite love I bear you, and also for fear lest the sudden cold, which in general disagrees so much with you, should have caused a return of your usual pains and other complaints. I therefore send the man who takes this letter purposely to hear how you are, and also when you expect to set out on your journey[1] I have been extremely busy at the dinner-napkins…As I have no cell of my own to sleep in, Sister Diamanta kindly allows me to share hers, depriving herself of the company of her own sister for my sake. But the room is so bitterly cold that with my head so infected, I do not know how I shall remain well, unless you can help me by lending me a set of those white bed-hangings which you will not want now. I would be glad to know if you can do me this service. Moreover, I beg you to be so kind as to send me that book of yours which has just been published, [3] so that I may read it, for I have a great desire to see it. These few cakes I send are some I made a few days ago, intending to give them to you when you came to bid us adieu. As you departure is not so near as we feared, I send them lest they should get dry. Sister Arcangela is still under medical treatment, and is much tried by the remedies. I am not well myself*, but being so accustomed to ill health, I do not make much of it, seeing, too, that it is the Lord's will to send me continually some such little trial as this…

10. Early Studies • He finds the period motion of a pendulum fascinating • Times each swing of the chandelier with his pulse • Periodic motion is fundamental in understanding gravity planetary motion • Tower of Pisa story apocryphal • Experimentalist

11. Gravity • Calculates the acceleration of gravity by rolling spheres down a ramp • Investigates the trajectory of projectiles • In 1537 Italian scientist Tartaglia said that the trajectory of a bullet was really a continuous curve • Says objects fall with the same acceleration, regardless of weight, contradicting Aristotle • If two objects are attached, do they fall faster?

12. Motion from Gravity • After 1 second an object rolls some distance x • After 2 seconds the object has rolled 4x • After 3 seconds… • Irrespective of weight! • Whereas for Aristotle rest was the natural state and motion required an “agent”, for Galileo motion was the natural state and a change in motion, acceleration, required an “agent”

13. NASA Proves it!

14. The Medici • Hugely powerful Florentine family from 13th to 17th century • Family produced three popes and many city-state rulers • Ran the most respected bank in Europe • 1605: Galileo serves as tutor to the Cosimo de Medici • 1609: Cosimo II becomes Grand Duke of Tuscany

15. 1609 • Galileo obtains a telescope from Flemish opticians • Invented by Hans Lippershey in 1608 • Galileo improves upon it • Always practical, Galileo tries to sell it to merchants • Affords a two hour advanced warning of incoming ships

16. Always curious: • Galileo points his telescope skyward • Sees ten times further than any man before • Traditional cosmology called into serious question • Sees the Moon is not perfect but covered with mountains and valleys

17. Recently discovered sketches of the Moon A place just like any other place: heretical!

18. Heresy • Sees the Moons of Jupiter in orbit • Proof that all things don’t orbit the Sun • Names the moons after the Medici heirs • “a confirmation of the Medici’s destiny, almost a scientific proof of their dynastic horoscope”

19. Imperfection • Sees that the Sun is covered with spots • Not the perfect Sun professed by the Church • Moving sunspots shows that the Sun rotates

20. Damning Evidence • Sees that Venus has phases just like the Moon • Explainable only if Venus orbits the Sun

21. 1610 • Resigned post at Padua • Took position of "Chief Mathematician and Philosopher" to Grand Duke Cosimo II • Published Sidereus Nuncius [Starry Messenger], dedicated to Cosimo II

22. Word gets out • Sir Henry Wotton, the British Ambassador to Venice, reports: • "strangest piece of news that hath ever yet received from any part of the world . . . these discoveries will certainly overturn all astronomy and astrology… [Galileo] runnetha fortune to be either exceedingly famous or exceedingly ridiculous."

23. Kepler to Galileo in 1610 • “Your observations concerning the sparkling appearance of the fixed stars, in contrast with the circular appearance of the planets, what other conclusions shall we draw from these differences, Galileo, than that the fixed stars generate their light from within, while the planets being oblique, are illuminated from without; that is to use Bruno's terms, "the former are suns, the latter are, moons or earths?" Nevertheless, let him not mislead us onto his belief in the infinite worlds, as numerous as the fixed stars and all similar to our own…” • . . . I rejoice that I am to some extent restored to life by your work. If you had discovered any planets revolving around one of the fixed stars, there would be awaiting for me chains and prison amid Bruno's innumerabilities, I should rather say, exile to his infinite space . . .

24. Disbelief • Devout people would view these phenomena through Galileo’s telescope and not believe what they were seeing • But they would believe it when they looked at ships at sea! • New instruments for Copernicanism raise questions: • Does the telescope help, or hinder our vision? • Does it extend, or merely distort our senses? • Aren't our eyes adequate to see all we are entitled to see? • Why would the natural world include things we can't see with our unaided eyes?

25. 1615 • Galileo writes a lengthy letter to the Grand Duchess Christina, Cosimo II’s mother • He expressed concern that theologians, ignorant of basic astronomical principles, risked erring through misinterpretation of scripture and misapplication of its authority to problems in natural philosophy

26. Reaction • 1614: A Dominican friar, NiccolòLorini, sends a copy of Galileo's letter to Rome as evidence of his heresy • Copernican theory is condemned by the Church • 1616: Galileo is called to Rome by Cardinal *Bellarmineand told to stop teaching the Copernican system • Galileo thinks that there is no heresy if you read his theories just the right way *remember him?

27. A prideful man, Galileo tries to counter ecumenicism with logic • Joshua 10:12-14: Then spake Joshua to the Lord in the day when the Lord delivered up to the Amorites before the children of Israel, and he said in the sight of Israel, Sun, stand thou still upon Gideon; and thou, Moon, in the valley of Ajalon. And the sun stood still, and the moon stayed, until the people had avenged themselves upon their enemies.

28. According to Galileo • [I]t is obvious that if the sun should cease its own proper motion, the day would become shorter, and not longer.... • The way to lengthen the day would be to speed up the sun's proper motion; and to cause the sun to remain above the horizon for some time in one place* ... it would be necessary to [accelerate] the customary speed of the sun about three hundred sixty times.... *Like going backwards on a moving sidewalk at the airport

29. Digging himself deeper • [Theologians] are forced to interpret the words in the midst of the heavens a little knottily, saying that this means no more than that the sun stood still while it was ... above our horizon. [U]nless I am mistaken we may avoid this and all other knots if, in agreement with the Copernican system, we place the sun in the "midst" -- that is, in the center -- of the celestial orbs of planetary rotations....

30. But a Chance to Dig Himself Out • 1623: Galileo's friend, Cardinal MaffeoBarberini, became Pope Urban VIII • The two had had long talks about Copernicanism before Barberini’s ascendancy • 1625: Galileo began writing a defense of Copernican theory, later to be known as Dialogue Concerning the Two Chief World Systems • First it was a treatise on the tides • Not a gravitational theory! • Tides happen because the oceans slosh due the Earth’s motion (proof!)

31. Characters • Salvati AKA Copernicus • Simplicio AKA Ptolemy • Simplicius was Aristotle translator • Sagredo, a scholar who asks questions of the two • Simplicio responds with Ptolemaic (and stupid) answers • Salvati gives the wise answers

32. Guess Who is Who? Simplicio Salvati • Galileo puts the words of his friend Barberini in Simplicio’s mouth • May have been an attempt at humor • The Pope was NOT amused!

33. The Inquisition • 1632: Galileo ordered to Rome to stand trial for heresy • Remember what happened to Bruno 32 years earlier? • Only his previous friendship with Barberini and letters of mercy from his daughter saved Galileo • The Medici disown him

34. Verdict: Guilty • Forced to recant his beliefs • Reported to have whispered as he was led away, “But [the Earth] still moves.” • Sentenced to house arrest for his last ten years

35. Final Years • 1631: Buys the villa "Il Goiello" in Arcetri, near Maria Celeste’s convent. • Maria Celeste takes care of him until she dies in 1634. • Comes back to his earlier studies of motion • 1638: Discourses and Demonstrations Concerning Two New Sciences published at Leyden • Relativity • 1635: Dialogue... translated into Latin and English • Banned in Catholic countries, but available in Protestant lands • He dies in 1642, the year Isaac Newton is born, 300 years before Steven Hawking is born

36. Epilogue • 1820: The Papal Inquisition is abolished • 1835: Dialogue Concerning the Two Chief World Systems is taken off the Vatican's list of banned books • 1992: The Catholic Church formally lifts the edict of inquisition on Galileo • Steven Hawking was invited to the ceremony • Gave a talk on the Big Bang • the late Pope John Paul II once told him that scientists should not study the beginning of the universe because it was the work of God • Here we go again?