Why were Mercury and Venus treated differently from the other known planets in Ptolemy's geocentric model of the universe?
A) They always appear close to the Sun.
B) They are the closest planets to Earth.
C) They do not exhibit retrograde motion.
D) They have the highest surface temperatures.

Question

Quizplus · Accepted Answer

Mercury and Venus always appear close to the Sun in the sky because their orbits lie inside Earth's orbit. In Ptolemy's geocentric model, this was explained by placing their epicycles (small circular orbits) on a deferent (larger circular orbit) that revolves around the Earth, with the centers of their epicycles always aligned with the Sun. This arrangement accounted for their observed behavior in the sky, distinguishing them from the other planets, which could appear anywhere along the ecliptic.

Why Were Mercury and Venus Treated Differently from the Other