Question

1. what is retrograde motion? retrograde motion is when a planet appears to go one way but then turn back around and go again in the same way like a loop. 12. what was the paradigm shift that occurred in astronomy at about 1500 ad? the paradigm shift that occurred in astronomy at about 1500 ad was

Explanation:

Retrograde motion is an apparent backward - motion of a planet as seen from Earth due to the relative positions and speeds of Earth and the planet in their orbits. Around 1500 AD, the major paradigm shift in astronomy was the transition from the geocentric model (Earth - centered universe) to the heliocentric model (Sun - centered universe), proposed by Nicolaus Copernicus. This new model challenged long - held beliefs and changed the way we understand the structure of the solar system.

Answer:

1. Retrograde motion is the apparent backward motion of a planet as seen from Earth due to relative orbital positions and speeds.
2. The paradigm shift was the transition from the geocentric to the heliocentric model of the solar system.