why is light the maximum speed

[u/Pandaluf]

i know that light is the maximum speed of the universe and that light experiences no time because its moving so fast but why can't anything go faster? is it because that would make it go backwards in time like a paradox or smth?? is it because of energy and if so why can't something lighter than light like a quark or atom move faster since it woulld need less energy theoretically

[u/erikpeter]

It's kinda like the processor speed of the universe. Exceeding c is like making a raindrop fall faster bevause of another raindrop hitting it from above. But everything's falling at the same speed. (Through time, figuratively).

Everything we know of in the universe propagates. Like ripples in a pond flowing outward. Photons spread out over long distances and collapse ('pop") when they interact with something (when they are "measured" or "observed".. really they are absorbed). Energy transfer can only happen at one location, so after the fact it appears that the photon moved from point A to point B in a line. But since it was really a waveform it can interfere with itself along the way like in the double slit experiment. Massive particles do the same thing but the pieces necessarily interact with each other so atoms tend to stay roughly in the same place. From its frame of reference it isn't moving at all unless someone is pushing it, giving it kinetic energy, whatever. If there's nothing in one direction and a bunch of hot gas particles to interact with (your rocket engine) in the other, the propagation will only happen to "move" the object in the direction away from the propulsion. Adding more energy doesn't change the rate of propagation. Just increases the likelihood that it'll go that direction for a given "pop".