Dimples help the golf ball fly. If you hit a perfectly smooth ball with no dimples, it will only travel half the distance. The USGA also requires golf balls and their dimples to be symmetrical, though there is no limit to the number of dimples. For optimal aerodynamics, modern golf balls have between 350 and 500 dimples. The distance, stability, and spin rate of the shot are all affected by the different shapes, sizes, and patterns. For example, the more dimples there are, the further the ball travels, but the spin decreases.