The Sagnac Effect is a phenomenon observed when light travels in opposite directions around a rotating platform. When a beam of light is split and sent in both directions, the light traveling in the direction of rotation takes longer to return than the light traveling against it. This results in a measurable difference in the arrival times of the two beams. This effect was first demonstrated by Georges Sagnac in 1913 and has important implications in physics, particularly in the fields of relativity and GPS technology. The Sagnac Effect helps to explain how rotating systems can affect the behavior of light and is crucial for accurate positioning in satellite navigation systems.