Figure 3-17 An Explanation of Orbits If a ball is dropped from a great height above Earth’s surface, it falls straight down (A). If the ball is thrown with some horizontal speed, it follows a curved path before hitting the ground (B, C). If thrown with just the right speed (E), the ball goes into circular orbit; the ball’s path curves but it never gets any closer to Earth’s surface. If the ball is thrown with a speed that is slightly less (D) or slightly more (F) than the speed for a circular orbit, the ball’s orbit is an ellipse.