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 spun on epicycles. The planets spun on epicycles. 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 correct response is: **The planets spun on epicycles.**

Ptolemy's geocentric model explained the apparent changes in speed and direction of the planets by proposing that each planet moved in a small circle called an epicycle, which in turn moved along a larger circle (the deferent) around the Earth. This complex system of motion accounted for the retrograde motion and varying speeds of the planets as observed from Earth.

Why was the geocentric model accepted for more than a thousand years?(1 point) Responses It correctly explained the motion of the planets. It correctly explained the motion of the planets. It correctly described the solar system. It correctly described the solar system. It correctly explained the distribution of the stars. It correctly explained the distribution of the stars. It was confirmed by astronomers using telescopes.

The correct response is: **It correctly explained the motion of the planets.**

The geocentric model, particularly as formulated by Ptolemy, was widely accepted for over a thousand years primarily because it provided a reasonable explanation for the observed motions of the planets, including their retrograde motion, and it fit well with the philosophical and religious views of the time that placed Earth at the center of the universe.

Which of the following describe Aristotle's model of the solar system? Select the three correct answers.(2 points) Responses The Sun is at the center. The Sun is at the center. Each planet is attached to a crystalline sphere. Each planet is attached to a crystalline sphere. The stars are attached to the outermost sphere. The stars are attached to the outermost sphere. Each planet spins on an epicycle. Each planet spins on an epicycle. The Earth was at a point slightly offset from the center. The Earth was at a point slightly offset from the center. Earth is at the center.

The three correct answers that describe Aristotle's model of the solar system are:

1. **Each planet is attached to a crystalline sphere.**
2. **The stars are attached to the outermost sphere.**
3. **Earth is at the center.**

In Aristotle's geocentric model, the Earth was considered the center of the universe, with planets and stars attached to a series of concentric crystalline spheres that rotated around it.