But FTL travel and time travel already exist. With the former, from an outside observer's reference frame, objects inside a black hole's event horizon appear to

But FTL travel and time travel already exist. With the former, from an outside observer's reference frame, objects inside a black hole's event horizon appear to use to travel faster than the speed of light. Not that it's all that practical. Also, a rotating black hole "drags" the spacetime around it. This means that the accretion disk can appear to rotate FTL really close to even horizon as it passes through the ergosphere. It's already traveling close to speed of light in its local frame, and you add frame dragging to it and you get an FTL total violation, from your reference frame. Of course it's a useless kind of FTL that you can't do anything fun with. For the latter, every astronaut in orbit is a time traveler since they are moving at such great speeds that they experience tie dilation. I believe the Juno spacecraft is the current record holder of time travel since it is the fastest man-made object. I'm not that smart, but I have my doubts about light being the universal speed limit. Baseless rant incoming: I never advanced that far in math, but I found the notion of infinitesimal limits and infinities hard to accept and they are most likely beyond observation if they do indeed exist. So I find the idea that it takes an infinite amount of energy to move a massive object at the speed of light to be a signal that perhaps although it is exceedingly accurate, that E=mc^2 doesn't quite tell the whole story. Waxing philosophical::