The Copernican Model & Kepler’s Laws

1. The Copernican Model & Kepler’s Laws DANIEL Boyle & Audrey Vitter

2. Scientific Paradigms According to Thomas Kuhn paradigms are “universally recognized scientific achievements that, for a time, provide model problems and solutions for a community of researchers” “Successive transition from one paradigm to another via revolution is the usual developmental pattern of mature science.” Transition to a heliocentric model of the universe is an example of paradigm shift

3. The Aristotelian Paradigm • 2 Sphere Universe (Celestial and Terrestrial) • 4 terrestrial elements: Earth, Water, Air and Fire • Each terrestrial element tends towards a natural place • Earth is naturally located at the center of the universe • One celestial element: Ether • Celestial bodies are immutable and move in uniform circles

4. Nicolaus Copernicus Born in Torun, Poland in 1473 and raised by his uncle Established an observatory at Frauenburg, and developed a reputation as an astronomer Invited to the 1514 Lateran Council to discuss calendar reform Major works include Commentariolus, Narratio Prima, and De Revolutionibus

5. De Revolutionibus Most of Copernicus’ work prior to De Revolutionibus was circulated as manuscripts De Revolutionibus was completed in 1530, but was not published until 1543 while Copernicus was on is death bed Georg Rheticus and other friends were instrumental in convincing Copernicus to publish his revolutionary work

6. Religious Climate Copernicus was hesitant to publish any of his work considering that it could be viewed as heretical Osiander’s preface to De Revloutionibus appeals to the instrumental character of astronomy It is likely that Copernicus actually saw his model as representative of reality Protestants felt the Copernican model was incompatible with scripture Counter-Reformation Catholicism bans De Revloutionibus in 1616

7. Pros of the Copernican Model Problems of retrograde motion and varying brightness are solved Proximity of the inner planets to the sun is explained Simple proof for order of the planets can be derived Fit to observation

8. Cons of the Copernican Model Features more epicycles than Ptolemaic system Does not completely eliminate equants Expands the universe to account for lack of stellar parallax Deconstructs Aristotelian physics

9. Is the Copernican Model revolutionary? Copernicus retains uniform circular motion Copernicus was largely attempting to repair problems with the Ptolemaic, not to overthrow Aristotelian cosmology “The significance of De Revolutionibus lies, then, less in what it says itself than what it caused others to say”- Kuhn

10. Tycho Brahe Born in 1546 in present day Sweden, and raised by his grandfather Lost his nose in a duel, and replaced it with gold Was said to own a clairvoyant dwarf It is rumored that Tycho had an affair with the Danish Queen Died as a result of holding his bladder too long

11. Tycho’s Work Witnessed a new supernova in 1572 which cast doubt on celestial immutability Built an observatory commissioned by King Fredrick II of Denmark in 1576 Observed a comet in 1577, which he proved was above Earth’s atmosphere Considered the greatest naked eye observer, his predictions of planetary position were within 4 arc minutes of actuality The accuracy and volume of his work opened the door for Kepler’s laws

12. The Tychonic Model Tycho noted the improvements that came with the Copernican model He was unable, however, to accept that Earth was in motion Tycho devised a system that was kinematically equivalent to Copernicus’

13. Johannes Kepler • December 27, 1571: Born in Weil der Stadt, Württemberg (Germany) • Premature baby, sickly • Lutheran • Witch ties • 1591: Graduated from University of Tubingen • Scholarship to study Theology • Formation of Copernicus beliefs • 1594: Professorship of astronomy in Graz, Styria

14. Mysterium Cosmographicum • The Sacred Mystery of the Cosmos • God made the universe with a mathematical beauty • Five Pythagorean regular polyhedral • Reflect God’s plan through geometry and symmetry

15. First Model • Why did the outer planets move more slowly? • Saturn vs. Earth • Later rejected • Initially blamed the discrepancies on errors in Copernicus' tables • http://www.uff.br/cdme/kepler/kepler-html/kepler-en.html

16. New Chapter • ~1658: Counter-revolution occurred • 1660: Left Prague to work for Tycho • Kepler made a bet that he could understand Mars’ orbit in eight days—took him eight years • 1601: Tycho died • Kepler took all his data under his care. • "I confess that when Tycho died, I quickly took advantage of the absence, or lack of circumspection, of the heirs, by taking the observations under my care, or perhaps usurping them...”

17. Ptolemy Model • Ptolemy Model • Used Tycho’s data to backup model • Precision allows error to be seen • error by eight minutes of arc • Threw out model • Wanted a “dynamically” explained model • Explain Mars orbital movement in “steady motion”

18. Development of the New Model • First step: Earth’s orbital • Thales’ method of Greek geometry • Two fixed points: Sun and Mars • “An idea of true genius” –Einstein • Kepler’s Second Law • In their orbits around the sun, the planets sweet out equal areas in equal times http://www.keplersdiscovery.com/Earth.html http://astro.unl.edu/naap/pos/animations/kepler.swf

19. Mars’ Orbital • “Oval” shape • Deviated by 0.00429 of the radius (AC) • AC/MC = 1.00429 • Secant(CMS) = 1.00429 • Later stated as an “ellipse” • Sun at one focus • Kepler’s First Law • The planets move in elliptical orbits with the sun at a focus

20. Astronomia nova • 1609: Findings were published • First Law • The planets move in elliptical orbits with the sun at a focus • Second Law • In their orbits around the sun, the planets sweet out equal areas in equal times

21. Gravity and Optics • Gravity • A mutual tendency between material bodies toward contact • The waters of the oceans being attracted by the moon’s gravitational pull caused tides • Optics • Focused on this topic after Galileo found four new planets by looking through lenses into the night sky • 1611: Published Dioptrice, a basic work on optics • The light intensity decreases with the square of the distance • Later became the principle of the camera obscura

22. Harmonices Mundi • Harmony of the World • Relates his findings about the concept of congruence with respect to diverse categories of the physical domain: • regularities in three-dimensional geometry • the relationships among different species of magnitude • the principles of consonance in music • the organization of the Solar System. • Full of errors and inconsistencies • Third Law: • The distance a planet is from the sun, cubed, is directly proportional to the time it takes to complete the orbit, squared. • The distance a planet was located from the sun directly determined the time it took that planet to revolve around the sun

23. Questions?

24. Works Cited Kuhn — The Structure of Scientific Revolutions Kuhn — The Copernican Revolution Cushing — Philosophical Concepts in Physics Koestler— Sleepwalkers