So, I've been looking at this chart Only Electro-magnetic force is carried by massless particle - photon. And it propagates at the speed of light. Now take Weak and Strong force. They are carried by bosons and gluons. They have mass. So, what is the speed of propagation of Weak and Strong forces, if that question makes any sense. It seems that it can't propagate at the speed of light because you can't have mass traveling at the speed of light.