Astronomy 161 -- Autumn 2007
In-Class Quiz 2 Study Guide


Unit 3: The Revolutions of the Heavenly Orbs
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Aristotelian World View
   Assumptions (uniform circular motion, fixed unmoving earth)
   Early Geocentric Systems
     Eudoxus, Pythagoras, Aristotle
   Epicyclic Systems
     Hipparchus & Ptolemy
   Early Heliocentric System
     Aristarchus of Samos
   Ptolemaic Geocentric System
     Epicycles
     Equants
     Preserving Appearances - esp. retrograde motion & 
           change in brightness of superior planets at opposition.
     Problems: complex, no way to measure planetary distances

Copernicus
   Motivations & Assumptions (disliked equant, wanted to restore
     uniform circular motion)
   Copernican Heliocentric System
     Sun at the center
     Earth rotates on its axis every 24 hours
     Earth orbits (revolves) around the sun once a year
     His use of epicycles and why he used them.
     Successes:
        a) explains superior & inferior planets
        b) explains retrograde motion
        c) gives a geometric way to measure planetary distances
     Problems: (a) moving earth 
               (b) stellar parallaxes

Tycho Brahe: his observations & their significance

Johannes Kepler: his theoretical work & its significance

Kepler's Three Laws of Planetary Motion
   First Law
   Second (Equal Areas) Law
   Third (Harmonic) Law

Galileo's telescope observations & their significance
   The Moon
   Sunspots
   Phases of Venus
   Moons of Jupiter

Isaac Newton: work and its significance
   Laws of Motion
      First Law (Law of Inertia)
      Second Law (F=ma)
      Third Law (Action & Reaction)


Unit 4: Gravitation, Light, & Matter
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Newtonian Gravity
   Inverse-Square Law Force
   Dependence of the gravitational force on masses and distance
   of the two bodies.
     
Newton's Generalized forms of Kepler's Laws
   Shapes of Orbits
   Orbit about the Center of Mass
   Circular and Escape Velocity
   Measuring Masses with Newton's form of Kepler's 3rd Law

Tides
   Basic causes of gravitational tides
   Earth Tides caused by the Sun and Moon
   Tidal Locking
   Tidal Evolution of the Moon's Orbit and Earth's Rotation
   Lunar Recession
   Increasing Length of the Day

Gravity in the Solar System
   Gravitational Interactions among objects
   Lagrange Points
   The discovery of Neptune
   Slingshot orbits
   Orbital Resonances (Galilean Moons, Pluto)