This has bothered me for some time. I must be missing something. Photons, being the massless particles that they are, have no inertia. So what holds them back from surpassing the "speed limit" at moving around with no time lapse. They would be everywhere simaltaneously. Does something hold them back? A hidden effect of dark matter, perhaps? Evidence gathered tells us it must be otherwise. But why? What can hold back a massless particle? Interest in the tachyon is up, and it intrigues me. Any help in this area would definitely be helpful.