HELIOCENTRIC MODEL Copernicus 16 th century Maybe things orbit
the sun instead of the earth? 1473-1543 AD Slide 2 Retrograde
motion easy to explain without resorting to further embellishments!
(like with epicycles) Slide 3 Copernicus could also explain a lot
about the differences observed in planetary movement! (Once again
without any fancy embellishments!) Superior and Inferior planets
Slide 4 Superior planets (orbits bigger than earths) opposition
conjunction Slide 5 Inferior planets (orbits smaller than earths)
never in opposition, but two kinds of conjunction
(inferior)(superior) Slide 6 Inferior planets (orbits smaller than
earths) never have elongations larger than a certain value greatest
EASTERN elongation: evening star greatest WESTERN elongation:
morning star Slide 7 Orbital periods of the planets As seen from
earth the planet repeats itself somehow. Synodic: Sidereal: Actual
amount of time the planet takes to orbit the sun, in reference to
the stars. How did Copernicus do it? Slide 8 (inferior) Start Slide
9 (inferior) Start Slide 10 (inferior) Start Slide 11 (inferior)
Start Slide 12 (inferior) Start Slide 13 (inferior) Start Slide 14
(inferior) Start (inferior again) Slide 15 (inferior) Start
(inferior again) S synodic period P sidereal period Angle Slide 16
(Earth)(Inferior planet) Slide 17 1546-1601 AD Tycho Brahe: Slide
18 Hven (now Ven) Slide 19 Uraniborg "The Castle of Urania" Slide
20 NS Giant quadrant Mounted on N-S axis, for measuring the
altitude of stars. Uraniborg Slide 21 Slide 22 A Tycho quadrant
Slide 23 Stjerneborg "castle of the stars". (Instruments
underground) Slide 24 Slide 25 1571-1630 AD Johannes Kepler:
analyzed like crazy Slide 26 Tycho Brahe: measured like crazy
Johannes Kepler Keplers Laws ! 1546-1601 AD 1571-1630 AD Slide 27 a
(Semi-major axis) b (Semi-minor axis) K.L. #1 Planetary orbits are
not circles, but ellipses! Eccentricity e a is also average
distance from either foci e = 0 to 1 Slide 28 average distance from
sun = semi-major axis Sun at one of the foci Slide 29 Ellipses with
differing eccentricities (but same a) Slide 30 Planeta (AU)eb/a
Mercury0.3870.2060.9786 Venus0.7230.0071.0000 Earth1.0000.0170.9999
Mars1.5240.0930.9957 Jupiter5.2030.0480.9988 Saturn9.5540.0530.9986
Uranus19.1940.0430.9991 Neptune30.0660.0100.9999 Eccentricity of
the planets? Slide 31 K.L. #2 The sun-planet line sweeps out equal
areas in equal times! [Angular momentum] slowest fastest Slide 32
slowest fastest perihelion aphelion Sun Slide 33 K.L. #3 For a
planet orbiting the sun ! a : orbit semi-major axis in AU P :
Orbital period in years Slide 34 Slide 35 NOTE: Two orbits with the
same a have the same period! (and vice-versa) Slide 36 Two
descriptive models, which is right? HELIOCENTRIC MODEL GEOCENTRIC
MODEL Slide 37 Galileo Galilei 1564-1642 found supporting evidence
for the heliocentric model Telescope! Slide 38 According to
Aristotelian principles the Moon was above the sub-lunary sphere
and in the heavens, hence should be perfect. Slide 39 SUNSPOTS Even
the sun isnt perfectSun rotates Slide 40 Moons of Jupiter (solar
system analog) Slide 41 Galilean satellites (Io, Europa, Ganymede
and Callisto) Slide 42 Phases of Venus Slide 43 Slide 44
