So I’m just going to throw stuff I’ve heard on the internet on here and hope that my beliefs are true. Feel free to post comments on them and your knowledge that you want peer reviewed (to the best of our ability that is).
Alright, so from what I know of FTL travel in the realm of actual science is that it would revolve around time distortion over velocity. This is due to the laws of physics stating that nothing can travel faster than the speed of light and as such if you were traveling 4 times the speed of light over 4 light years that means you would only experience 1 years of time while the rest of the universe experiences 4.
Next up falls into the same type of science as FTL, wormholes. From what I know of worm holes, they are both tears in space and time. Since nothing can travel faster than the speed of light that means that going from one point to another 5 light years away then stepping through the wormhole takes you 5 years into the past or future.
Now here’s my knowledge of fusion technology. I understand how it works due to many videos and articles explaining it, however, the thing I think is true but might not be is why it is inefficient. From my knowledge, the reaction produces the amount of energy we want but a lot of it is lost through a miniature version of a solar flare making the energy burst out and be lost.