Light appears almost instantaneous to the naked eye. This seems especially evident on the Fourth of July, watching a firework explode, only for the boom to hit you seconds after the colorful light hits your eyes. It does not seem like something so fast and instant could be affected by a force such as gravity. However, gravity actually has the ability to effect rays of light; not in the way you would expect. Light doesn’t have weight like matter does.
According to the Theory of General Relativity, mass warps the space around it, creating the effect of gravity. This warp in space is what has the ability to bend light. Beams of light passing through this warp is moving in a straight path, yet is bending through this warp. Therefore, the light does not appear to be moving straight to an outside observer. It does not actually have an effect on the speed of light, just the path it follows.
The idea that the force of gravity effects more than just the mass that we see on a daily basis is pretty wild – its effect can bend the light which generates the image we see when we look up into the sky.