What you're experiencing in that image is refraction and diffraction. 'God rays' happen when the sun shines through a series of small gaps, typically through cloud. The light is then reflected multiple times through the structure in several directions until it's absorbed by the cloud or comes to a gap leading to the ground below. The diffraction is why we can see it so clearly. Welcome to the world of basic science, question. If the earthy was flat, how do we get a night time? It's impossible to have a night time for a flat earth because that's not how light, or the sun works. The sun is a powerful ball of luminous gas caused by nuclear fusion, so: A) If it was small and didn't produce much light then it would have exploded by now, so, it has to be big. B) If it's big and close to the earth to try and make less light hit the areas that are in night time, then we'd have a nice earth barbeque. Hope that clarifies that light is one of the major disproves and, here's a funny thing. About 3-4000 years ago, the Greeks used light to work out how round the world was. Spooky huh.