University of Florida Homepage

Ptolemaic Cosmos vs. Copernican Cosmos

Subtopic:

 The scientific and religious implications of a heliocentric universe rather than a geocentric universe or the beginning of the scientific revolution

Objectives:

  1. The students will be able to list differences in the diagrams of a geocentric universe and a heliocentric universe.
  2. The students will be able to describe the religious impact of this change on man’s conception of the universe and man’s place within it.
  3. The students will be able to describe the impact of the Copernican view on cosmology of the late sixteenth and seventeenth century.

Activity 1:

2 periods

Materials:

 DIAGRAMS OF THE PTOLEMAIC UNIVERSE AND COPERNICAN UNIVERSE

Procedure:
  1. Using the overhead projector, hand out of diagrams, or drawings on chalkboard, a presentation and explanation of the two diagrams should be made.
  2. Using brainstorming, the students will list the differences between them.
  3. A brief lecture on the position o the Roman Catholic Church and Protestants should be made with emphasis on the geocentric universe.
  4. The students should discuss the implications of the heliocentric system on the Roman Catholic position.
  5. A brief lecture on the impact of Copernican theory on Galileo, Kepler, and Newton should conclude.

Bibliography

Crowe, Michael J. Theories of the World From Antiquity to the Copernican Revolution. New York: Dover Publications, 1990

Kagan, Donald. The Western Heritage. New York: Macmillan, 1983.

Kearney, Hugh. Science and Change 1500-1700. New York: McGraw-Hill, 1974


Attachment #1

Ptolemaic Universe

Based on a general framework of Aristotelian physics which had dominated medieval thought, the concept of the Ptolemaic Universe was a mathematical nonobservational approach. It was based on the following basic premises of ancient astronomy:

  1. A geostatic and geocentric cosmos. The earth did not move and was the center of the universe as the sun and all planets revolved around it.
  2. Celestial bodies possess uniform, circular motion around a central point.
  3. Celestial bodies are composed of a fifth element, the quintessence.
  4. The cosmos is finite.

Copernican Universe

Nicholas Copernicus (1471-1543) was a mathematical, not an observational, astronomer who sought to purify ancient astronomy, not to overthrow Ptolemy. By allowing the earth to move, many of the difficulties of traditional astronomy would be overcome. The Copernican system was based on the following basic premises:

  1. Introduction of three celestial motions.
    1. Diurnal (daily) rotation of the earth on its axis
    2. The earth, and the planets revolve around the sun (heliocentric)
    3. A conical axial motion of earth to explain the fixed orientation of earth in space

Problems of the Copernican System

The main disadvantage of the Copernican system was its violation of Aristotelian physics–the physical problems involved with the heliocentric system called for a new, as yet nonexistent, physics.

Diurnal rotation of the earth on its axis as well as the geliocentrism of the universe were to meet considerable resistance from people who had been taught to believe that the earth was stationary and at the center of the universe. People using “common sense” could deny that the earth moved as there was no sense of motion. When a stone was thrown up in the air, it fell straight down, not further back.

Protestant View of the Copernican System

The first religious leaders to denounce Copernicus for contradicting the Bible were Luther and Calvin, but they did not officially condemn him.

Martin Luther said, in his work, Tischreden:

There was mention of a certain new astrologer who wanted to prove that the earth moves and not the sky, the sun and the moon. This would be as if somebody were riding on a cart or in a ship and imagined that he was standing still while the earth and the trees were moving. So it goes now. Whoever wants to be clever must agree with nothing that others esteem. He must do something of his own. This is what that fellow does who wishes to turn the whole of astronomy upside down. Even in these things that are thrown into disorder I believe the Holy Scriptures, for Joshua commanded the sun to stand still and not the earth. (Crowe 174)

ROMAN CATHOLIC VIEWS OF THE COPERNICAN UNIVERSE

By 1500, the dominant intellectual influence upon theology was Aristotle. Aristotelian terms were used to explain terms in church doctrine. The Ptolemaic universe was based on Aristotelian physics. When Nicholas Copernicus published his De Revolutionibus Orbium Coelestiu in 1543, the Protestant Reformation had been going on for years. At first the Church followed a policy of nonintervention. By the year 1600 the Roman Catholic church was deeply involved in the Counter Reformation against Protestants trying to bring back those lost to Protestantism and strict interpretation of Church doctrine was essential.

The Copernican Idea of a heliocentric universe raised more than questions about the literal interpretations of the scriptures. Some of the following could be raised:

  1. If there were more than one planets, would God have placed man on only one?
  2. If all men were descended from Adam, how could men on other planets be descended from him?

A CHRONOLOGY OF THE SCIENTIFIC REVOLUTION 

1267-1273 St. Thomas Aquinas writes Summa Theological integrating Catholic theology and Aristotelian philosophy

1517 Martin Luther posts his Ninety-Five Thesis which begins the Protestant Reformation

1543 Nicholas Copernicus publishes On The Revolutions of the Heavenly Bodies

1571 Tycho Brahe develops instruments for precise astronomical observation and records positions of stars and planets. He creates a Tychonic System of the universe called reoheliocentric. Planets revolve around the sun except the earth. The sun and planets still revolve around the earth.

1600 Giordano Bruno, a famous Italian philosopher who had espoused Copernicanism and an infinite universe, was tried Inquisition and burned.

1609 Johannes Kepler publishes his first and second Laws of Planetary motion. (l) Planetary orbits are elliptical. (2) Planets move faster the closer they are to the sun

1609 Galileo Galilei perfects the telescope to 30X magnification and begins observations

1619 Kepler announces his Third Law of Planetary Motion which stated that a planet’s distance from the sun is related to the time it takes a planet to revolve around the sun

1632 Galileo publishes his Dialogues on the Two Chief Systems of the World which popularized the Copernican system and articulated the concept of a universe subject to mathematical laws

1633 Galileo is denounced by the Inquisition and forced to recant his belief in Copernican theory

1667 Sir Issac Newton constructs the first reflecting telescope

1687 Newton publishes his Mathematica Principia which explained gravitation, contained the components of Newtonian Physics (matter, motion, space, attraction), and destroyed the Aristotelian/Ptolemaic universe.


Bibliography

Morrison, Philip and Phylis Morrison. Ring of Truth. Random House, 1987. (Video version also available) 

Rutherford, Watson, Rinehart and Winston. Project Physics. 1975.