DARK AGES

1

• DARK AGES
• Fall of Rome in 410 A.D.
• Most information from previous civilizations lost
• Knowledge saved in Middle East
• Greek and Latin manuscripts translated into
  Arabic
• Eventually returned to western Europe

2

• Epicycle as used by Ptolemy (geocyntric model) go
  to

3

• Copernicus (1473-1543)
• The sun is at rest (heliocyntric model)
• The earth is spherical
• Planets revolve about sun
• Periods of revolution decrease with orbit radii
• The motion of planets about the sun involve
  epicycles (34 circles)

4

• Tycho Brahe (1546-1601)
• Danish Astronomer
• Developed accurate astronomical instruments
  (quadrant )
• Built elaborate observatory
• Plotted motions of planets
• Improved measurements of Greeks by a factor of 6
  ( 5 of arc )

5

• Johannes Kepler (1571-1630)
• http//es.rice.edu/ES/humsoc/Galileo/People/kepler
  .html
• Used Tychos Data and developed three laws of
  Planetary motion
• Firmly established heliocentric theory
• Published his results in 1609, 1618

6

• Keplers Laws
• Orbits are elliptical
• Orbits sweep out equal areas in equal times
• Period2 Distance3
• (If Period in in years and Distance is in AU)
• (AU - astronomical unit - distance between earth
  and sun)

7

• Galileo Galilei( 1564-1692 )
• http//es.rice.edu/ES/humsoc/Galileo/
• Constructed 30x telescope
• Phases of Venus
• Structure on moon

8

• Moons of Jupiter
• Sunspots
• Many new stars
• Structure of Saturn

9

• Galileo
• Studied the motion of falling bodies
• Refuted the teachings of Aristotle
• Reinstituted the scientific method
• Suffered under the reformation
• Published the Dialog Concerning the Two New
  Sciences in 1638 at age 70
• Began the modern sciences of astronomy and
  mechanics

10

• Newton (1642 - 1727)
• Developed Mechanics
• (study of motion)
• To do this had to invent Calculus

11

• Newtons Laws of Motion
• A body in motion will remain in motion unless a
  force acts upon it.
• Force mass times acceleration (F m a)
• Every action has an equal and opposite reaction

12

• Newtons Law of Universal Gravitation
• Note that it depends upon 1/r2

13

• Motion of moon (see p. 19 of text)