Which are features of Copernicus's model of the solar system? Select the three correct answers.(2 points)
Earth is fixed to a crystalline sphere.
Earth is fixed to a crystalline sphere.
The outer planets move in epicycles.
The outer planets move in epicycles.
The Sun is at the center.
The Sun is at the center.
The planets move in perfect circles.
The planets move in perfect circles.
The stars are fixed to an outer sphere.
The stars are fixed to an outer sphere.
All planets orbit the Sun at the same speed
The Sun is at the center and the planets move in perfect circles are two correct answers.
The three correct answers are:
1. The Sun is at the center.
2. The planets move in perfect circles.
3. The stars are fixed to an outer sphere.
The three correct features of Copernicus's model of the solar system are:
1. The Sun is at the center.
2. The planets move in perfect circles.
3. The stars are fixed to an outer sphere.
To arrive at this answer, let's analyze each option:
1. Earth is fixed to a crystalline sphere.
This is not a feature of Copernicus's model but rather the geocentric model, where Earth was believed to be fixed at the center of the universe. Copernicus's model, on the other hand, placed the Sun at the center.
2. The outer planets move in epicycles.
Epicycles were part of the Ptolemaic model, which was the geocentric model before Copernicus's heliocentric model. In Copernicus's model, the planets moved in perfect circles around the Sun.
3. The Sun is at the center.
This is correct. Copernicus's model placed the Sun at the center of the solar system, marking a shift from the geocentric model.
4. The planets move in perfect circles.
This is correct. Copernicus believed that the planets moved in perfect circles around the Sun, although later observations and advancements in astronomy showed that their orbits were actually ellipses.
5. The stars are fixed to an outer sphere.
This is correct. In Copernicus's model, the stars were believed to be fixed to an outer sphere surrounding the planetary orbits.
6. All planets orbit the Sun at the same speed.
This statement is not part of Copernicus's model. In his model, the planets were still believed to move at different speeds based on their distance from the Sun.