Please don't destroy me I'm utterly out of my league. Totally admit it. Never took a math class beyond college algebra (a proud, passing C) and no physics not even 101. Yes I suck. Ok so just intuiting but isn't distance always going to be a subjective measurement of space between objects...including the famous e=mc^2...light ALWAYS travels through a medium, space isn't a vacuum. I can slow the speed of light by blocking it; space is chuck full of crap we can't see (dark matter and such). So if light travels through 70% dark matter at x speed, 68% dark matter would make it speed up right so what is the real measurement? And what is a vacuum anyway? No space at all? So is Distance just the measurement of something traveling through a fixed medium? The space between things is therefore a measurement of what literally lies in the way of a beam of light? Take that out and you got what? Nothing, right? That's a true vacuum? Without anything truly lying in the way of light there really isn't such a thing as distance? Seriously I dont know. And none of my idiot non physics friends here know either. So please take us mensch out of our misery and just tell me. us the 'speed of light' something that is more of a 'moving target'?