Ptolemy's model of the solar system explained the apparent changes in speed and direction of the planets by stating that the planets spun on epicycles. This means that planets would move in small circles (epicycles) as they orbited larger circles (deferent), allowing for the observed complex movements including retrograde motion.
Aristotle and Ptolemy Quick Check
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Question
How did Ptolemy's model of the solar system explain the apparent changes in speed and direction of the planets?(1 point)
Responses
The planets were attached to crystalline surfaces.
The planets were attached to crystalline surfaces.
The planets were fixed to nested spheres.
The planets were fixed to nested spheres.
The planets had a significant stellar parallax.
The planets had a significant stellar parallax.
The planets spun on epicycles.
1 answer