The difference between C and sound are quite a bit - C is literally the fastest any object can travel, whereas sound was just an engineering limitation.
Now, whether or not we can find shortcuts AROUND C, that's another thing entirely.
Just when you thought you'd gotten to C, C's still larger. :-P
Cheers, Ben
About the use of language: it is impossible to sharpen a pencil with a blunt axe. It is equally vain to try to do it with ten blunt axes instead. -- Edsgar W. Dijkstra