Lecture 6: Copernican Revolution

"Happy is he who has been able to learn the causes of things."

Virgil, Georgics

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    • Date: September 15, 1994
    Reading Assignment: pp. 40-47

    Description : Introduction to the Copernican Revolution, including the work of Copernicus and Galileo. Introduction to the Heliocentric Model.

    Objectives

  • be able to explain the essential features of the Heliocentric Model.
  • be able to discuss the contributions Copernicus made to this model
  • understand how the geocentric model produces Retrograde motion
  • Understand and explain how the observations of Galileo verified the Geocentric Model
  • understand the impact the "Sidereal Messenger" and the "Dialogue" had on western thinking

    • Lecture Outline

    Slide # 1: Lecture 6: The Copernican Revolution

  • Copernicus
  • Galileo
  • Tycho
  • Kepler
  • Newton
    • Slide # 2: Lecture 5: Dead Greeks
  • Measuring Distances
  • The Size of Earth
  • Apparent Motion of Planets
  • The Geocentric Model
    • Slide # 3: Revolution
  • an orbit around a celestial object
  • a change in a political system or way of thinking
    • Slide # 4: The Copernican Revolution: A Brief Historical Overview
  • Italian Renaissance- early 15th Century
  • End of the "dark ages"
    • Slide # 5: Copernicus wrote a Book
  • De Revolutionibus Orbium Coelestim
  • (On the Revolution of the Celestial Spheres)
    • Slide # 6: De Revolutionibus
  • Not a Best Seller
  • Listed on the Index of Banned Books 1616-1822
    • Slide # 7: The Geocentric Model Solar System
  • Accepted Model of the Universe Before 15th Century
    • Slide # 8: The Heliocentric Model of the Solar System
  • Developed by Copernicus
    • Slide # 9: Foundations of Copernican Revolution (see p. 42)
  • The Earth is not Center of Everything
  • The Moon revolves around the Earth
    • Slide # 10: Foundations of Copernican Revolution
  • Planets revolve around the Sun
    • Slide # 11: Foundations of Copernican Revolution
  • Stars are too distance to easily measure parallax
    • Slide # 12: Foundations of Copernican Revolution
  • The sky is fixed and the Earth rotates
    • Slide # 13: Foundations of Copernican Revolution
  • The Sun is fixed and the Earth revolves around it.
    • Slide # 14: Foundations of Copernican Revolution
  • Retrograde Motion is Caused by the Earth's Revolution
    • Slide # 15: The Geocentric Model Slide # 16: No Epicycles!?
  • are all the epicycles gone?
    • Slide # 17: Copernican Epicycles
  • some epicycles are still needed
  • a simplier model for the solar system
    • Slide # 18: The Inner Planets
  • travel faster than Earth
  • are closer to the Sun than Earth
    • Slide # 19: Inner Planets Slide # 20: Position #1 - Earth, Venus and Sun in Conjunction
  • Alignment between 3 objects
    • Slide # 21: Positions #2 - Venus Rises Before Just Before Sun Slide # 22: Position #3 - Venus further away from the Sun Slide # 23: Position #4- Maximum Elongation Slide # 24: Position #5- Venus Appears Close to the Sun Slide # 25: Position #6- Venus Approaching Conjunction with the Sun Slide # 26: Inner Planets- The View From Earth
  • Venus Before Sunrise
    • Slide # 27: Inner Planets- The View From Earth
  • Venus After Sunset
    • Slide # 28: The Outer Planets
  • travel slower than the Earth
  • are further from the Sun than Earth
    • Slide # 29: The Outer Planets Slide # 30: Position #1 Slide # 31: Position #2 Slide # 32: Position #3 Slide # 33: Position #4 Slide # 34: Position #5 Slide # 35: Position #6 Slide # 36: Position #7 Slide # 37: Outer Planets- The View From Earth Slide # 38: Giordano Bruno
  • Advocated and taught the Heliocentric Model
  • Judged to be a heretic
  • Burned at the stake
    • Slide # 39: Galileo
  • first systematic astronomical observations using a telescope 1609
  • published "Sidereus Nuncius" in 1610
  • The Starry Messenger
    • Slide # 40: The Starry Messenger
  • An observational log of what he saw with his telescope
  • Contained 5 important observations
    • Slide # 41: Galileo's Big Observations
  • 1. The Moon has mountains and plains like Earth
  • the Moon is a planet like Earth
    • Slide # 42: Galileo's Big Observations
  • 2. Venus has phases
  • Venus orbits around the Sun
    • Slide # 43: Inner Planets Slide # 44: Inner Planets- The View From Earth
  • Venus Before Sunrise
    • Slide # 45: Phases of Venus
  • Venus has phases which change during its orbit
    • Slide # 46: Galileo's Big Observations
  • 3. Jupiter has Moons
  • not everything revolves around the Earth
    • Slide # 47: Galileo's Big Observations
  • 4. The Sun has Spots
  • it is not a perfect sphere
    • Slide # 48: Galileo's Big Observations
  • 5. There are stars which are not visible without a telescope
  • not everything in the sky was made just for humans
    • Slide # 49: Galileo's Second Book
  • "Dialogue Concerning the Two Chief World Systems"
  • Described why a Geocentric Model would not work.
  • Published in Italian, not Latin
  • Very widely read
    • Slide # 50: The Church's Reaction
  • Galileo arrested 1633
  • Placed under house arrest until his death
    • Slide # 51: Lecture 6: The Copernican Revolution
  • Copernicus
  • Galileo
  • Tycho
  • Kepler
  • Newton
    • Slide # 52: Next time: Tycho, Kepler and Newton