Describe the Ptolemaic model of the solar system. How did Ptolemy account for th

Although Ptolemy's model was an Earth-centered model of the solar system, it was sufficiently accurate to remain in use for 1,500 years. His model used the ancient idea that all motions in the heavens must be perfect circles. Therefore, the planets moved on circles that orbited on larger circles around Earth. This "circle upon circle" motion accounted for the apparent retrograde motion of the planets. Ptolemy carefully selected sizes for the circles to reproduce the motions seen in the sky. He also placed Earth slightly off-center to improve model predictions even more.