Things like light waves and radio waves move at a similar speed. So in stead of saying radio waves travel at the speed of light, which is true, saying "the speed of information" also makes sense, because that's basically the univeral limitation for information to travel. However, I've heard that gravitational waves are said to move at the speed of information as well. If the sun were to disappear, we wouldn't actually fly out into the galaxy until another 8 minutes or so. If the same applies with light, and light is made up of photons, would gravity be made up of some physical thing like photons are? Photons are able to be sent out and absorbed. Gravitational waves are able to move at the same speed as light, so wouldn't it be delivering some sort of physical communication?