TheSkaFish said:
Total newbie question here, but are black holes the thing that some people say could be somehow connected to time travel? If so, what do they mean?
Yes, but there are debatable technicalities as per the mathematics.
The science fiction suggestion is that like someone above said, black holes can be used as wormholes or shortcuts.
However, mathematically applied, you would need a counter-current ripple in order to contrast the progression of linear space-time dynamics.
Or in simple English: You would need another black hole, and then the merger of those two black holes.
Such as what was detected by LIGO.
There IS actually a mathematical, theoretical, legitimately plausible consideration for time travel with the idea of the merger of two Supermassive Black Holes. In that, there is a pathway that you could theoretically take in between the two, in which space-time would be so incredibly distorted, that you could see the entire experience of the universal expansion, in reverse...
You couldn't "alter" the past, or even really interact with it, it'd be more like watching a movie. BUT a movie that explains literally everything that we don't already know. (in theory, that is).
The trouble is that the mathematical problem for this is actually so great that literally nobody is working on it in the field of Astrophysics, not even Stephen Hawking before he died. We don't have the technological advancement to begin studying something like that, is the thing. Hawking agreed at some point that we simply just do not have the instruments to prove that yet.
We JUST NOW photographed the invisible...
Trying to mathematically expand upon its technical endeavors as to what it can/does do outside of what we already know, however...
Is a different story entirely...
We don't have instruments that can mathematically dissect and properly accommodate things like Dark Matter and Dark Energy, and so we have problems like The Vacuum Catastrophe, wherein subatomic particles can be seen interacting with each other in the pockets of empty, isolated space, and we have no idea why...BECAUSE we don't have the technology to be able to explain that yet.
Solving The Vacuum Catastrophe would likely require some funding for experimental scientific inventions, such as CERN with the LHC which took like 40 years to develop, or LIGO, which took around about 30 years or the same amount of time. What I'm trying to explain is: We WILL get there, it just likely won't be during my lifetime (considering that I'm 30 years old).
But what should give us hope within the world of science is that scientific assumption has been wrong before (many times, and has often lead to amazing discoveries as such) it is, however, science...meaning that it accepts its failures as factual evidences regardless of generalized social assumption. That's the whole reason I'm drawn to science in the first place: Even if it's wrong in its own assumption, it just accepts it as a new discovery anyways and keeps going based upon that discovery and treats that discovery as an evolution of itself. That's how physical science works. ^_^