Light & Color

Corner Reflector

Three mirrors arranged perpendicularly to each other form an interesting type of reflector. Light rays that enter the corner exit parallel and opposite to their original direction. When visitors look into this set of mirrors, they see themselves with their dominant eye centered at the vertex of the three mirrors. A set of these reflectors in the form of prisms was left on the moon by the Apollo astronauts, allowing scientists to determine the distance to the moon to an accuracy of 6 inches.