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 had a significant stellar parallax.
The planets had a significant stellar parallax.
The planets were fixed to nested spheres.
The planets were fixed to nested spheres.
The planets were attached to crystalline surfaces.
The planets were attached to crystalline surfaces.
The planets spun on epicycles.
The correct answer is: The planets spun on epicycles.
Which of the following describe Aristotle's model of the solar system? Select the three correct answers.(2 points)
Responses
Each planet spins on an epicycle.
Each planet spins on an epicycle.
The stars are attached to the outermost sphere.
The stars are attached to the outermost sphere.
Earth is at the center.
Earth is at the center.
The Earth was at a point slightly offset from the center.
The Earth was at a point slightly offset from the center.
The Sun is at the center.
The Sun is at the center.
Each planet is attached to a crystalline sphere.
The correct answer is:
The planets spun on epicycles.
The correct answer is "The planets spun on epicycles."
To understand how Ptolemy's model of the solar system explained the apparent changes in speed and direction of the planets, we need to understand what epicycles are. In Ptolemaic astronomy, an epicycle is a small circular orbit whose center moves around a larger circular orbit, called a deferent. The planet is placed on the center of the epicycle, and as the epicycle moves around the deferent, the planet appears to move in a complex motion, including apparent changes in speed and direction.
By using the concept of epicycles, Ptolemy's model allowed him to account for the retrograde motion observed in some planets. Retrograde motion is the apparent backward motion observed when a planet seems to move opposite to its usual eastward motion across the sky. It occurs when the Earth, on its own orbit, overtakes and passes the slower-moving outer planet.
This complex system of epicycles, deferents, and eccentric circles helped Ptolemy explain the observed celestial motions. While it was not an accurate representation of the actual solar system, it provided a way to account for the observed planetary motions from Earth's perspective.