Explanation:
Ptolemy was an Alexandrian Astronomer and mathematician. In 150AD, he presented his model of the universe. It was a modified version of the then accepted Geocentric model of the Universe. Some of the highlights of the model were:
1. Earth is at the center of the universe and stationary.
2. Every celestial object is revolving around the Earth.
3. In order to explain the motion of the Sun, he introduced eccentric motion of the Sun. As per this model the point around which the Sun revolved was displaced from the Earth. Thus the Sun will move faster when at perigee and slower when at apogee.
4. To explain the motion of planet, he introduced the concept of epicycles. According to him the planets revolved around a point in a circular motion and that point revolved around Earth. This also accounted for the retrograde motion of the planets.
