[3niner]

Dumb question alert: why is the speed of LIGHT specifically supposedly the ceiling on speed?

Not a dumb question, but it's not practical to answer it here. Einstein's General Theory of Relativity implies this (his earlier, Special Theory of Relativity didn't go far enough to be definitive).

Of course, if one actually understands the "General Theory", it still leaves a tiny amount of room for doubt, since it's unlikely we have final and complete understanding on this subject.

[sola_fide]

I haven't read all of the 300+ posts on this thread, so someone may have already said this. BUT, the theory of General Relativity most emphatically does not imply that nothing can travel faster than the speed of light. However, it does imply that nothing my break through that "light barrier" if you will. In other words anything travelling slower than the speed of light can never go faster than c; nothing travelling faster than c can ever go slower than c.