Speed of Reality
There's nothing more constant than every scientist's conviction regarding the speed of light. It's a universal speed limit. Nothing can go faster. Even gravity itself travels at the speed of light (or super close, anyway). This means if the sun goes dark, we won't know until enough passes for the last photon to reach us. If the sun winks out of existence, the loss of gravity won't be experienced until the same amount of time passes.
How's that for nuts? We're traveling in a big circle around a center of gravity; even if that center of gravity disappears, we'll continue traveling in a circle as though it was still there. For a few minutes, at least. On larger scales, it could continue for much longer periods of time. Reality changed way over there, but reality hasn't changed right here. Yet.
So, the speed of light, aka speed of gravity, is also the speed of reality. However, I'd like to point out that saying gravity "travels" bothers me a little bit. It's like saying a wave on the ocean travels... a wave isn't a real thing that you can pick up and put down somewhere else. It's a phenomenon that exists ephemerally in a medium. It's just a distortion of that medium and I see gravity "waves" as the same thing. Two neutron stars collided and produced immense gravity waves that our detectors can pick up? Ripples of space-time are more accurate. So if a gravity wave is just an undulation of space-time, that means space-time itself cannot react any faster than it does - it can't propagate anything faster, including light.
Given all that; let's think about time travel. If you want to access the reality of 100 years ago, I don't think going faster than light is the answer. I believe that it represents a type of time travel - you would get to experience the reality local to a distant exploding star before that reality was experienced by Earth. You would have to race away from the Earth and the star at super-luminal speeds and then you could overtake the reality wave and live in a past reality. That's not the same as going to last week and stopping yourself from driving to the local grocery store and getting into a fender bender.
Now, if you wanted to speed away from the Earth, in the opposite direction of the center of the universe, and you had an absurdly powerful telescope, you could view last week and see yourself drive to the local grocery, and have the accident. But that reality is moving away from us at all times, along the ripples in space-time. Distance is required because reality is moving. You can't sit in the same place and experience the local reality from last week. It's very far away.