You may change your mind as often as you wish. When you are satisfied with your
responses, click the SUBMIT button at the bottom of this page. Don't submit more
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in your browser), you have the two competing "world views" for explaining the
motion of the planet Mars against the stars. Ptolemy used "epicycles" or circles inside
circles, (Applet 1) Kepler used ellipses centered on the Sun
(Applet 2). The data that Ptolemy had to work with couldn't tell the difference between the
two "world views". Kepler had the data from Brahe's observatory, which was much better than the
Greeks (or Chinese, or Mayans or Aryans...). Compare the two predictions against the different quality
data sets using the hidden buttons at the bottom (Applet 3). Now answer the following questions.
What explanation does Ptolemy have for "retrograde" or reverse motion of Mars? What exactly
does his explanation "mean"?
What explanation does Kepler(Copernicus) have for retrograde motion? Does it "mean" anything more than
What purpose (meaning) is there is making measurements of something that has already been measured?
(E.g., what are the metaphysical reasons for repeated measurements?)
You may change your mind as often as you wish. When you are satisfied with your responses,
click the SUBMIT button.
I received no help from anyone on this assignment.