Galileo Galilei Or: How a telescope can get you into trouble This logo denotes A102 appropriate In Context: These changes, Copernicus through Galileo, all occurred during the Renaissance Roots in the 13 th century Florence with Dante (The Inferno) and Petrarch (humanist philosophy) Composers 15 th century Ockeghem and 16 th century Gesualdo Artists Bruegel the Elder, Raphael, and Michelangelo And the Renaissance man, Leonardo da Vinci Compare Bayeux Tapestry 11 th C Pieter Breugel 16 th C 1
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 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!) 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 2
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? Gravity NASA Proves it! 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 1609 3
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 Recently discovered sketches of the Moon A place just like any other place: heretical! 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 Heresy 4
Imperfection Sees that the Sun is covered with spots Not the perfect Sun professed by the Church Moving sunspots shows that the Sun rotates Damning Evidence Sees that Venus has phases just like the Moon Explainable only if Venus orbits the Sun 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 5
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 1615 Reaction 1614: A Dominican friar, Niccolò Lorini, 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 *Bellarmine and 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? 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... 6
But a Chance to Dig Himself Out 1623: Galileo's friend, Cardinal Maffeo Barberini, 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!) 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 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! 7
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 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 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 8
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? 9