Transcript Geocentric Models

Unit: _____________
PHENOMENON:
What did you observe?
What evidence do you have?
OBJECTS:
Define the system.
What objects are
interacting?
Topic: __________________________
MOTION:
Describe the motion that in the model
that explains your observations
MODEL:
Diagram of the model that
Describes the motion and
observations (evidence)
Aristotle (350 B.C.)
Greek
• Formulated a picture of the solar system
that put Earth at its center with all the
other heavenly bodies orbiting around it.
• GEOCENTRIC model
• The orbits were described as perfect
circles.
The retrograde (backward, looping) motion of Mars.
A composite image created by superimposing images taken on twenty-nine different dates.
The “Wanderers”
 The Greeks continued to watch the night sky,
 The Sun, moon, stars moved predictable orbit in the
sky.
 BUT, there were five “objects” that did not follow this
regular, predictable motion
 Once every year, they’d move BACKWARDS
(retrograde) for a month or two!!
 They “wandered”, thus called planetes
(Mercury, Venus, Mars, Jupiter Saturn)
Observations
Watch the animation and make observations
about the motions of the planets and the Sun on
your handout
• http://www.davidcolarusso.com/astro/
Ptolemy (Greek)
A.D. 140
 Attempted to make a MODEL of the solar system that
explained the motions of the planets you just
observed!
 The model had to be testable by predicting future
motion of the planets
What does Ptoloemy’s model look like?
Then construct a model to explain the observed
motion of the planets
Ptolemy’s model of the Solar
System/Universe
Epicycle
To be continued….
http://www.youtube.com/watch?v=GevV1yvMJbc
History Channel
 http://www.youtube.com/watch?v=utH-
GHH1FT8&feature=related
 Ptolemy