I don't know whether I should post this under cosmology, but since it's mainly about light rays so I'll put it here. I was reading Hawking's book and a thought suddenly struck me. Since light travels in a straight line, if I direct a torchlight into the night sky, if the light isn't reflected back by any particle on the way, and if it managed to travel through the atmosphere perpendicularly(or not exceeding refractive index of the atmosphere) would it escape from the earth? 2. If it managed to escape successfully, and if the universe really has so many stars, would the light of the torchlight end up falling on a distant star many years later?