Galileo: Father of Modern Science

1
Galileo Father of Modern Science

• Talk given
• by
• Dr. Alan Bates
• at
• The American University of Rome
• for the
• 2008 Winter Term Study Project
• History of Revolutionary Science
• DePauw University
• 22 January 2008

2
Galileo Father of Modern Science

• Historic and Scientific Background
• Galileo and Science
• Galileo and the Church

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Historic and Scientific BackgroundHellenic
Physics

• Aristotelian Model of Universe (384 322 BC)
• Circle is the perfect shape without change
• Geocenteric universe
• Universe divided into Celestial (perfection) and
  Sub lunar regions (imperfection)
• Aristotle and Motion
• Free Fall motion dependent on mass
• Objects at rest stay at rest
• Aristotle to Ptolemy (90 168 AD)
• System of epicycles to account for retrograde
  motion
• Saving appearances

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Historic and Scientific BackgroundDark and
Golden Ages

• Dark Age (476 1000)
• No alternatives to Ptolemys model
• Islamic Golden Age (700 -1200)
• Expansion of Islamic civilization about the
  Mediterranean
• Discovery of Greek manuscripts translation into
  Arabic and later into Latin
• Incorporation of thinking of Aristotle into
  Christian Theology Thomas Aquinas (1225 -1321)

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Historic and Scientific BackgroundThe Renaissance

• Renaissance in Italy
• Rediscovery and incorporation of the Classic
  world into daily life of a citizen
• Florence was Renaissance capital of Italy
• Cittadino expected to live up to artistic,
  intellectual and moral heritage
• Galileo born in 1564 son of a Cittadino

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Galileo and Science The Pendulum

• Galileo observed swinging lanterns in Cathedral
  of Pisa
• Related length of pendulum to time of swing
• Measure time with improved accuracy
• Measurement of velocity
• Measurement of heartbeat

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Galileo and Science Free Fall and the Inclined
Plane

• Galileo related inclined plane to free fall
• Dilution of gravity on inclined plane allowed
  accurate measurement of time
• All objects independent of mass roll down incline
  at same rate contradicts Aristotle
• The End of Hellenistic Physics

8
Galileo and Science Copernicanism and the
Telescope

• Copernicus (1473-1543), a Polish monk, was first
  to propose a heliocentric model of the universe
• Copernicus published his On the Revolutions of
  the Heavenly Spheres in the year of his death
• The book was dedicated to Pope Paul III
• Osiander added the preface declaring the
  heliocentric model to be a geometric device for
  fitting observation

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Galileo and Science Copernicanism and the
Telescope

• Galileo had already accepted Copernicanism before
  telescope observations
• Galileo directs his eyepiece (1610) at the
  heavens to witness
• Craters on the Moon
• Moons of Jupiter
• Sunspots

10
Galileo and Science Copernicanism and the
Telescope

• Aristotles model of Universe does not fit
  observations celestial world should be perfect
  without change
• Galileo publishes Starry Messenger (1610) and
  Letters on Solar Spots (1613). Both are instant
  successes and propaganda for Copernicanism
• Galileo believes he can win support of Pope Paul
  V (1616)

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Galileo and the ChurchThe Order of 1616

• Galileo travels to Rome for a private meeting
  with Cardinal Bellarmine
• Bellarmine is instructed by the pope to advise
  him Galileo to abandon the said opinion
  Copernicanism
• If Galileo refused to obey an injunction he was
  to be imposed to abstain from teaching or
  defending that doctrine and opinion or from
  discussing it
• If he did not agree Galileo was to be imprisoned

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Galileo and the ChurchThe Order of 1616

• Galileo was not imprisoned however two surviving
  documents of the meeting are inconsistent
• Two months later Galileo requests a letter from
  Bellarmine certifying what happened at the
  meeting
• The doctrine of Copernicus is contrary to Holy
  Scripture and therefore cannot be defended or
  held
• Another account, unknown scribe, was deposited in
  files of Holy Office
• Galileo is ordered to relinquish altogether the
  said opinion, namely, that the sun is in the
  center of the universe and immobile, and that the
  earth moves nor henceforth to hold, teach, or
  defend it in any way, either verbally or in
  writing

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Galileo and the ChurchBetween 1616 and 1633

• Galileo returned to Florence not having knowledge
  of document on file in Holy Office
• Work on Copernicanism left untouched for eight
  years
• Cardinal Bellarmine dies in 1621
• Cardinal Barberini of Florence elected pope in
  1623 with name of Urban VIII
• Galileo engaged over six conversations with Urban
  VIII
• Galileo convinced the time was right to continue
  work on Copernicanism and started his Dialogue
  Concerning Two Chief World Systems, Ptolemaic and
  Copernican

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Galileo and the ChurchBetween 1616 and 1633

• Dialogue published in 1632 after passing censors
• Dialogue is a discussion, as opposed to the
  contemporary scientific monologue, taking place
  over four days
• Three characters are Salviati (Supporter of
  Copernicanism), Simplicio (Aristotle thinker) and
  Sagredo (Neutral layman)
• Copernicanism wins the four day discussion
• Roman Inquisition stops printing of book and
  confiscates copies

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Galileo and the ChurchThe Inquisition of 1633

• Urban VIII, under pressure from anti-Galileo
  priests, orders Galileo to Rome
• Inquisition includes four depositions (April
  June 1633)
• Inquisition questions Galileos loyalty and
  obedience rather than ideas of Copernicanism and
  its truth or falsity
• No known witnesses of 1616 meeting with Cardinal
  Bellarmine
• Galileo, believed to be threatened with torture,
  answers
• I do not hold this opinion of Copernicus, and I
  have not held it after being ordered by
  injunction to abandon it. For the rest, here I am
  in your hands do as you please.

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Galileo and the ChurchThe Inquisition of 1633

• Galileo was imprisoned in the dungeons of the
  Holy Office at the liberty of the Inquisition and
  that for three years to come you repeat once a
  week at the seven penitential Psalms
• The Dialogue is banned by the Inquisition
• Galileo returns to Tuscany under house arrest is
  forbidden from following intellectual pursuits

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Galileo and the ChurchAfter 1633

• Two New Sciences published in 1638 in Holland
• Galileo dies in 1642. Newton is born the same
  year.
• The Dialogue is dropped from the Index of
  Prohibited Books in 1835
• The Catholic Church acknowledges injustice done
  to Galileo (1979)
• Pope John Paul II speaking to scientists at an
  event to commemorate the centenary of Einsteins
  birth
• Collaboration between religion and modern
  science is to the advantage of both, and in no
  way violates the autonomy of either.