I don't see how we can say the speed of light is X value. Here's why: Imagine you are driving 50mph then a cop comes up driving beside you at 50 Mph too. If he aims his gun out his window and clocks you it would read 0 Mph right? So to get your real speed he would have to look at his own speedometer first to determine his speed in relation to the earth's surface beneath his vehicle no? So if the Earth is spinning around the axis at X, slinging around X miles per hour in our solar system, and our solar system is slung around our galaxy at X unknown miles per hour, and our galaxy shoots around the universe at X unknown miles more, even then we still have to ask, is our universe traveling at X speed through a Mega-verse, then how is it that we can say the speed of light is always X without comparing that in relation to something that isn't moving at all in the mega-universe stopped or at least start calculating the velocity of our speedometer in relation to such a non-moving point in space, if one even exists. We don't even know the size of the universe, nor where the center point is, so how in world can we say that light travels across the universe at X miles per hour, heck, we don't even really know how long an hour is since time is relative, from that vantage point isn't light different speeds at different locations all over the universe as is relative to the speed of the non-stationary locations of a speed detector? I mean sheesh, if I were a particle of light, I would think "I" light travel at 0 miles per hour, am the center of all things, and consider everything else around me here on earth to be moving at the speed of 'mass' or 299,792,458 m/s, the exact opposite, you know, like when your car is stopped at the light, then the car beside you moves so you think your are moving, but nope, they are. Maybe light is stationary, that's why it doesn't need energy to move through space, and lives forever, because it is sitting in one place until we matter slam into it at the speed of light?! It doesn't make a bit of sense at all when you think about it... Why do we always consider ourselves to be the stationary center that can judge the speed of all things when clearly it is we that are in a constant state of movement expending tons of energy that we can calculate to keep us in motion?! It makes more sense to say light moves at 0 mph, we are in fact the ones in motion!