sentences:  Stars were embedded in a large outer sphere which rotated relatively rapidly, while the planets dwelt in smaller spheres between—a separate one for each planet.To account for apparent anomalies in this view, such as the apparent retrograde motion of the planets, a system of deferents and epicycles was used.The planet was said to revolve in a small circle (the epicycle) about a center, which itself revolved in a larger circle (the deferent) about a center on or near the Earth.