Gravitational waves and light are fundamentally different phenomena, and their behaviors are governed by different principles. While light requires a medium to travel through, such as a vacuum or a material medium like air or glass, gravitational waves do not require a medium for propagation.
Light is an electromagnetic wave, composed of oscillating electric and magnetic fields. These waves require a medium to propagate because they interact with charged particles in that medium. For example, in the case of light traveling through space, it interacts with the electrically charged particles present in the vacuum of space. However, light can also travel through other transparent media like air or glass, where it interacts with the charged particles in those materials.
On the other hand, gravitational waves are a consequence of the theory of general relativity, which describes gravity as the curvature of spacetime. According to this theory, massive objects, when they accelerate, can create ripples in the fabric of spacetime itself. These ripples are what we refer to as gravitational waves.
Unlike light, gravitational waves are not electromagnetic in nature. They are disturbances in the curvature of spacetime that propagate outward from their source at the speed of light. They do not require a medium to travel through because they are not composed of particles like photons. Instead, they are waves in the very fabric of spacetime itself.
In summary, while light requires a medium for propagation, gravitational waves do not. Gravitational waves are disturbances in the fabric of spacetime, while light is an electromagnetic wave that interacts with charged particles in a medium.