Copernicus: Beginning a Revolution

Question 1

Copernicus bio (kinda)

Answer 1

1473-1543
First in post-antiquity to assert heliocentric model
Did NOT intend to demote Man’s central place in universe - only wanted simpler, more accurate mathematical model
Hoped to achieve this by merging Ptolemy and Aristarchus
Wanted to remove sacrilegious Equant
Last of the Ancients

Question 2

De Revolutionibus Orbium Coelestium

Answer 2

On the revolutions of heavenly spheres
Published just before Copernicus died
Not a church problem (wanted more accurate calendar for religious holidays)
He had no direct evidence for moving earth and his indirect evidence was real weak (Aristotle people wouldn’t be convinced)

Question 3

Aristotle earth isn’t moving stuff

Answer 3

The earth isn’t moving, I can’t feel it! I’m not dizzy!

Question 4

Copernican model

Answer 4

• nicely explains retrograde
• added smaller epicycle than Ptolemaic, eccentric
• all uniform circular motion
• has 34 circles

Question 5

Copernican model VS Ptolemaic model

Answer 5

Both have eccentric
Copernicus avoids Equant but makes up for it with epicycle
Copernican LESS accurate and MORE complicated
Both need many epicycles for better accuracy (Fourier series)

Question 6

Problems with Copernican model

Answer 6

• not more accurate
• not less complicated
• earth not centre of universe (physical/philosophical problems)
• earth revolving and spinning (more physical/philosophical problems)

Question 7

Advantage of Copernican model

Answer 7

Breaks scale invariance
Angular data can determine planets orbital radii
And can find correct order of planets (only 1 arbitrary scale parameter)
So Copernicus constructed first qualitatively correct model of solar system