送交者: steven 于 2005-5-04, 19:16:18:
回答: Thank you. Lets make it clear. 由 cornbug 于 2005-5-04, 18:28:47:
The centrifegal force is actaully acts on the earth. Unless a satellite is in a parabolic, or hyperbolic orbit, which the satellite will escape the earth gravitational force, the satellite is always falling back to the earth. However, because of the curvature of the earth, they satellite can never fall back to the earth, because when the gravity caused the satellite to drop from its tengential trajectory, the earth surface also "drop." As long as the orbit eccentricity is between 0 and 1, which basically means the orbit is circular or elliptical, the satellite keeps orbiting around the earth. The reason for satellite falling back to earth is because the drag force slows the satellite down, and causes the sateelite keeps changing to a lower orbit, and eventually reenters the earth.