Light maintains a constant speed in a vacuum but can appear to accelerate when changing direction, particularly when passing through varying densities, such as in the Brachistochrone curve scenario. In a rotating reference frame, light can exhibit coordinate acceleration, which complicates its behavior. The discussion touches on the concept of momentum conservation, suggesting that the deflection of light by a prism could be measurable in terms of force. A thought experiment involving the weight change of a prism when light is turned on or off is mentioned, highlighting the complexities of light's interaction with matter. Overall, the conversation explores the nuances of light's behavior under different conditions and frames of reference.