The best analogy for this I've read is that your motion through spacetime is constant. Think of a quarter circle dial with an arrow that goes all the way from 0

The best analogy for this I've read is that your motion through spacetime is constant. Think of a quarter circle dial with an arrow that goes all the way from 0 degrees (no relative movement in space) to 90 degrees (relative speed of light). The faster you go through space, the slower you go through time. The effects of this are barely noticeable until you get near the speed of light. This effect is time dilation. This, I believe, is the general relativity view of spacetime. What I like most about this is that it highlights the importance of understanding the domain of a function. The above shows how any object with rest mass has a space velocity domain of [0, c). People really don't want this to be true so latch on to any wild theory that would seem to bypass this cosmic speed limit, be it wormholes, FTL drives or whatever. Pretty much all of these theories rely on taking an equation with a domain over real numbers and plugging in negative values for things like mass. Garbage in, garbage out. I mean if mass can be negative, why limit yourself to real numbers? Why not a complex number for mass? As to why this is the case and how to reconcile it with a quantized view of spacetime... is beyond my pay grade.