does gravity affect light?
Gravity affects light in much the same way it affects matter. Gravity can bend a beam of light, and if powerful enough, it can keep light from escaping something that is emitting light. But the effect is very weak, and we don’t see it in everyday life. It was predicted by Einstein’s theory of general relativity, but only confirmed by observation relatively recently. Generally speaking, you can see the bending effect only with things that are very heavy, and very far away. There is a phenomenon called “‘gravitational lensing,” in which something very large, like a galaxy, takes the light from something even farther away, like another galaxy, and bends the light emanating from it and focuses it at us. It is a little like holding a magnifying lens near a candle. Not all of the light gets caught by the lens, but some does, and for somebody in exactly the right spot, the light is intensified. Here is a diagram of how that happens. Light from the distant galaxy on the right is being focused
