While many people might scoff at the very concept, light pollution is fast becoming a serious problem. Light pollution most commonly occurs when the beam of a high-wattage fixture is aimed toward the sky. When a spotlight is used to illuminate statues or buildings, for example, some of the light falls on its intended target, while the rest of the light beam is left to scatter into thin air. The result is an effect called urban sky glow, which is essentially a giant shroud of misdirected light that hangs over a city in the night sky. While some may find this phenomenon picturesque when seen from an airplane, it is the reason why only the very brightest stars are visible to citizens of urban environments. As light pollution continues to increase, it is entirely possible that future generations of city dwellers will not be able to see any stars at all.