Answer:
1.Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
2.They thought, if the heavens are divine, and the gods created man, well then certainly the universe must be geocentric, meaning the Earth is the center of the universe. Ancient societies were obsessed with the idea that God must have placed humans at the center of the cosmos (a way of referring to the universe).