As we know, light travels in straight line in normal circumstances, but when exposed to gravity it bends. But does it actually bend? I actually mean to ask whether if we take light as wave creating itself at next point in space, it seems to be that it does not generate next field at a point that is not straight ahead of it, but actually the point that was straight ahead (at which it would generate next field) has shifted due to gravity.
So isn't light moving straight in gravity?
Light moves in a way that's as close to taking a straight path as it's possible to get. According to general relativity, massive objects bend the spacetime around them. (Not just space is warped, time is intimately involved too.) The thing about curved spacetime is that if you zoom in very closely on a small patch of it, the idea of a straight path still makes sense. But if you zoom out, the space is all curvy, and so there's no hope of having straight lines. So if you want to predict how light will move, zoom in and draw your line a little bit at a time, doing your best to keep it going in the same direction. The word to google here is "geodesic", or "null geodesic" for light in particular. So while the light is really doing its best to go in a straight line, the fact that spacetime is curved unavoidably causes its path to bend.
