How does it seem to be that space/time always equals $c$? Given the way objects move, they seem to be going all the same "velocity" so to speak, that velocity being the speed of light. Except, velocity is displacement/time, so if something goes faster, the displacement is equally balanced by the reciprocally changing time factor so that it always balances out to 299,792,458 m/s. Well, that's the way it appears to be. The faster something displaces, the slower time moves for it; the slower something displaces, the faster time moves for it. These two factors always balance out to equal $c$.
Why is this? Is there something obvious and mathematical I'm missing about it, or is this a little deeper? Explanations perhaps? Deeper insight on this factor? It seems very interesting. 
Why is it that spacetime is always $c$? Is it simply what we use to observe it, and anything we observe it with is always traveling at $c$....jeez it's so freaking weird.
I could be completely wrong though; please clarify if so, but honestly, $E = \frac{mc^2} {\sqrt{1-\frac{v^2}{c^2}}}$ –
it's freakin' weird.
 A: Actually you're quite correct, though possibly not in the way you expected. Ordinary velocity isn't an invariant because obviously different observers moving at different speeds will measure different velocities. However there is an invariant form of velocity called the four velocity that is an invariant under special relativistic (i.e. Lorentz) transformations. The magnitude of the four velocity is always $c$ - the speed of light.
The reason the magnitude of the four velocity is always $c$ is because it measures the speed at which we move through time as well as the speed with which we move through space. This may seem strange because surely the speed we move through time is always one second per second - and indeed it is as long as you're measuring your own velocity in your own inertial frame. However if you're measuring the velocity of someone moving relative to you then time dilation will slow their clocks. If $t$ is their time and $\tau$ is your time this means $dt/d\tau$ is not equal to one second per second i.e. the rate at which they move through time has changed.
The end result is that if someone is moving relative to you, i.e. $dx/d\tau \ne 0$, then $dt/d\tau < 1$ and the two effects balance out to keep the magnitude of the four velocity at $c$.
