Title: Nicolaus Copernicus
1Nicolaus Copernicus
- Born 1473 Torun, Poland
- Died 1543 Frauenburg, Poland
2(No Transcript)
3Background and education
- Wealthy family
- Started education at University of Krakow
- moved to University of Bologna, Italy
- studied canon law
- moved to University of Padua, Italy
- studied medicine
- moved to University of Ferrara
- studied canon law - doctorate 1503
4Career
- Taught mathematics in Rome
- became canon at the University of Frauenburg
this position supported his astronomical studies - these date from Bologna
- roomed with an astronomer, Novara, who was the
official astrologer for the city - exposed to criticism of astrology and Ptolemy
5Background
- At this time - mathematics, astronomy and
astrology were intimately associated - problems with Ptolemy were that the order of the
planets was indeterminate (Venus and Mercury) - Structure of the zodiac was in question
- Copernicus tried other ways of arranging things
6Heliocentric system
- Fixed Sun at center of circular orbits for all
the planets - including Earth - All planets move at constant velocity along these
circular orbits - order of things was Mercury, Venus, Earth, Mars,
Jupiter, Saturn - Earth was just another planet
7Successes
- Explained the difference between the inferior and
superior planets - allowed the determination of the period for each
planet - allowed the determination of the distance of each
planet from the Sun
8Results
- . Period Distance
- Mercury 88 days 0.39 AU
- Venus 7.5 mo. 0.72
- Earth 1 year 1
- Mars 2yrs 2mo 1.6
- Jupiter 11.9 yrs. 5.2
- Saturn 29.6 yrs. 9.5
9Results cont.
- In other words, the distance and period give the
same order of the planets in the solar system - simple explanation of retrograde motion - see the
website following - http//csep10.phys.utk.edu/astr161/lect/
retrograde/copernican.html
10Remaining errors
- Circular orbits
- Constant velocity
11Publications
- 1503 wrote the Little Commentary but did not
publish it. - Visited by Georg Rheticus, mathematician, who was
impressed by the heliocentric view - Urged Copernicus to publish the book, undertook
to do this - No unpleasant response to this
12Role of Osiander
- This encouraged Copernicus to publish a larger
work On the revolutions of the heavenly spheres - Rheticus moves and cannot proceed with the new
book - Along comes Andreas Osiander, experienced with
publishing technical books
13Osiander
- Takes on the task of publishing De
Revolutionibus - inserts a letter to the reader before the text
saying that a) ideas presented did not represent
truth, b) it was impossible to know the causes of
heavenly phenomena - book appears in 1543 just as Copernicus dies
14(No Transcript)
15Major Conflict
- Geocentric versus heliocentric
- Extremely different views of the world
- But no clear way to decide which is true
- Needed more accurate observations of the planets
- Also needed improvements in Copernican view
16Interplay of theory and obs.
- Theory due to Copernicus
- Better (more accurate) observations need new
observing tools - Along came Tycho Brahe
- More accurate observations spur improvements in
the theory - Along come Kepler and Newton
17Old technology
- Hand held instruments
- made of wood
- small and non-standard instruments
18Astronomical and civil uses
19Brahe
- Danish nobility, wealthy, fascinated by astronomy
(a precursor of Percival Lowell) - interested also in alchemy
- lost part of his nose in a duel - gold
replacement - was given an island by the Danish king, Hven,
near Copenhagen for an observatory
20Brahe
- He represents a new kind of scientist, a
professional who did big science - 1546-1601
- A transitional figure - between the apex of naked
eye observations and the telescope (1608)
21(No Transcript)
22Astronomical observations
- Observed the nova of 1572 - supposed to be a
terrestrial phenomenon - Brahe showed the nova was far away (parallax)
- Aristotle said it (nova) could not exist
23Astronomical observations
- Jupiter passes Saturn
- predictions were off by days to months
- Comet of 1577
- Aristotle said comets were terrestrial phenomena
(in the atmosphere) - Brahe showed that the comet was placed among the
planets (parallax)
24(No Transcript)
25Island of Hven
26www.hven.com/EUBORG.htmlwww.hven.com/ELKRKART.htm
l
27(No Transcript)
28Brahes observatory on the island of Hven as it
is today.
29(No Transcript)
30(No Transcript)
31View of scale on the great mural quadrant
32Brahes improvements
- Metal instruments
- fixed and therefore more stable
- large and therefore more accurate
- built a complete laboratory with printing shop,
fabrication shops, assistants - continuous observations (vital)
- corrected for refraction
- also proposed a cosmological theory
33(No Transcript)
34Observations
- Normally, observations of a planet were only made
at a few positions in its orbit - Brahe had observations made continuously each
clear night
35(No Transcript)
36Tychonic system
37Brahes weaknesses
- Strong on observation
- weak on mathematics and theory
- enlisted the help of Kepler in 1600 at Prague
- at his death (1601), Brahe left his observations
to Kepler - Kepler published the best planetary positions
(Rudolphine tables)
38Johannes Kepler
- Born 1571
- Died 1630
- he was convinced that the universe was designed
according to geometrical principles (God was a
geometer) - trained as a mathematician
- imperial mathematician to Rudolf II
39Challenge
- Calculated the positions of the planets and
compared with Brahes observation - Worst agreement was for Mars
- He spent 4 years trying to explain the orbit of
Mars
40(No Transcript)
41(No Transcript)
42Geometry aspect
- Kepler asked the question why are there only 6
planets? - Answer there are 5 platonic solids
- cube, octahedron, tetrahedron, dodecahedron, and
icosahedron - he used these solids to position the planets
about the sun
43Platonic solids
- Cube - 6 faces -- earth
- tetrahedron - 4 faces -- fire
- octahedron - 8 faces -- air
- dodecahedron - 12 faces -- aether
- icosahedron - 20 faces --water
44Cube
45Tetrahedron
46Octahedron
47Dodecahedron
48Icosahedron
49Scheme
- Pick a solid (for example, the cube)
- start with a large sphere, solid inside touching
the sphere - place another sphere inside the solid so that the
sphere touches the solid - the planet moves in a circular orbit defined by
the sphere - then, place another solid inside the sphere so
that its corners touch the sphere
50(No Transcript)
51(No Transcript)
52Something new
- Kepler thought that the sun had an influence on
the planets (he didnt know about gravity) - Problem action at a distance
- William Gilbert publishes a book on magnetism
- Kepler sees how this could couple the planets
with the sun - first physical explanation
53(No Transcript)
54First law
- Using the observations of Brahe, Kepler decides
that the planets move in elliptical orbits - ellipse is a distorted circle
55- The Sun is at one of the foci
- therefore, the planet is closer to the Sun during
part of the orbit - and further away at other times
56Second law
- How did the planets velocity vary with distance
from the planet? - Three ways to do this
- velocity varies as 1/distance
- equal areas in equal time
- uniform velocity as viewed from the empty focus
57Equal area
58Second law cont.
- Kepler could not determine which was correct
- the observations were not good enough
- the problem remained until Newton
59http//csep10.phys.utk.edu/ astr161/lect/history/k
epler.html
60Third law
61Third Law
Earth distance 1 AU period 1
year Jupiterdistance 5.2 AU period 11.85
years
62Final test
- Calculate the positions of the planets and
compare with observations - these were the Rudolphine tables
- 30 times more accurate than the predictions of
Copernicus
63Curiosity
- Planets do not follow elliptical orbits
- this is due to the gravitational attractions of
each planets for all the others - the observations of Brahe were not good enough to
show this - otherwise Kepler might have been misled
64Music of the spheres the belief that the planets
as they moved about the Sun generated music which
could not be heard but could be understood
intellectually
65(No Transcript)
66(No Transcript)
67(No Transcript)
68Problems
- There still remained resistance to Copernicus
- largely theological
- what was needed was someone of stature who could
sell the idea - Galileo