Question

why did scientists struggle for thousands of years to accurately describe the solar system?
venus has phases like the moon.
many people spoke italian and did not understand latin.
the planets appeared to move backward in the sky occasionally.
scientists could not explain why the sun appeared to rise and set every day.

Explanation:

• Venus having phases like the moon was actually evidence that supported the heliocentric model (Galileo's observation), so it was not a reason for the struggle.
• Language (Italian - Latin) has no direct relation to the struggle in describing the solar system accurately.
• The apparent retrograde motion of planets (planets appearing to move backward in the sky occasionally) was a major confusion in the geocentric model. In the geocentric model (Earth - centered), it was hard to explain this motion without complex epicycles. In the heliocentric model (Sun - centered), it is a result of the relative motion of Earth and other planets as they orbit the Sun.
• The Sun rising and setting is due to Earth's rotation. Even in the geocentric model, they had a (wrong - in terms of Earth not moving) explanation for it (like the Sun orbiting Earth), so it was not the main reason for the long - term struggle.

Answer:

The planets appeared to move backward in the sky occasionally.