Gravity exists between matter and its strength between any two bits or groups of matter varies with the distance between them. When that variance is within a certain frequency range, such as particles orbiting a nucleus, it will be detected by our eys or instruments sensitive to that range, and we will "see" the matter. When matter does not move in such a regular frequency we will not detect its presence the same way but do detect it from its gravitational impact on things we do see...dark matter? Same stuff, different motion.
It may be the speed of gravity we detect and light, vision, warmth, growth, cell change, etc. is what happens depending on what it impacts. Heresy, I know...but...gravity moves things, sometimes in repetitious patterns and sometimes not.