I have explained in this post why time travel is impossible, and cannot happen at all. I base my argument on the assumption of humanity's approach towards inventions: In the long run, they propagate through every society. Thus, any time machine created would create havoc on universe in the eventually. We would have to be born in a universe where time travel already exists.
As a corollary, faster-than-light (FTL) travel also does not exist in our Einstein universe. The theory of relativity makes FTL travel impossible without time travel to the past. So if time travel can never exist in our universe, neither can FTL.
Even if my argument about time travel is wrong, and time travel can happen, the problem is still there: We cannot have FTL travel without time travel taking place. In other words, if we got beamed to Alpha Centauri (4.5 light years away) right now and came back, we would wind up in Earth 9 years ago. (If this does not sound right, bear with me, I will explain why in a another post.)
But then we have FTL travel almost like a standard element in sci-fi literature. This bugs me. Of course I understand that sci-fi is fiction, but even fiction needs to have some internal consistency. We rarely have people moving through walls in sci-fi, because if that happened, that would make firearms and bullets useless, and thus it is internally inconsistent. Why, then, do we have FTL travel, which is equally inconsistent, although not immediately noticable?
This is my problem with FTL travel happening without time travel: Since the concept makes a relativistic universe impossible, I need that explained in the plot. Why is FTL travel possible without time travel if everything else looks exactly the same as my own universe? I find it easier to come to terms with Tolkien's or Ursula LeGuin's universes: At least they don't pretend to be a future version of our universe. Ironically, this makes them more consistent than sci-fi.
To add to the insult, it seems to me that a relativistic universe has much better, unexplored (less explored) possibilities for literary experimentation. In a world where planets are separated by an impossible time barrier, we have one-way voyages that do not exist in our world today. Colonizing families are almost like the first colonists in America, except in that the voyage takes at least 10 years, or maybe even a lifetime. Families become separated, they do not just take a trip, they are taking a trip with absolutely no possibility on return to their previous lives. Where, in a society, would you find such people who are willing to take this type of risk, but are also capable of running a super spaceship?
Imagine the necessity of a rescue mission in the face of this time barrier. The help signal would be received years after and the rationality of a rescue mission would be questionable, given that the survivors may have already perished.
We could (even necessarily would) have people slowly evolving in different directions on different planets.
The literary possibilities created by a trip where a return voyage are impossible, seems to me to be endless.
Since information would actually travel at the speed of light, we would have a universe where information spreads faster than people. We would have societies separated in that they cannot have population exchange, but these people would have information exchange, albeit with a lag, of at least a few years. We would learn what happens at the other end of the galaxy after twenty thousand years. We could have teenagers trying to come to terms with the fact that their music idol from another planet has long withered and died. Or better still, not withered and died, but 30 years older than they thought him to be, and on the way to their planet to spend the rest of his days. Broadcasting from a spaceship, he would age two or three times faster than his fans. Am I the only one who thinks that this presents a great possibility for exploration?
I want a relativity-friendly sci-fi literature. Anybody know any good stories or novels?