I have a few theories on time travel:
1) If time travel is possible it cannot transport people. Otherwise there would be too many time travellers among us.
2) Paradoxes: A spacetime paradox (kill your grandfather etc.) is just a scar on the face of the universe. Just as you don't die if you scar yourself, the universe doesn't dissapear because it is scarred.

OK, the second theory is a bit far fetched, but if the first one is wrong then the second has to be right, as a person going back in time would make a very subtle change that would cause a paradox.

Yes time is slowed down for them...
It would allow you to travel 50 light years and age only a small fraction of that...

Maybe I misunderstood what you are saying , but it is not like that
"Time slowing down " is symmetric
Suppose you are in the year 3000
A 20 years old astronaut leaves the earth travelling at the speed of the light
He reaches a planet 50 light\years far away from the earth and he immediatly comes back
When he arrives at home , he is 120 years old, he did not age just a fraction of time !
Nothing has changed from the point of view of the astronaut (because of time symmetry)
The point is that the time on the earth on his arrival is not 3120 but let's say
3850

Well, keep in mind, that if he were actually going the speed of light, then according to the equation, the entire universe has begun and ended in an instant for him (time is no longer rellevent).

...for him (time is no longer rellevent).

I am not so sure about this point or maybe I misunderstood both you and koh

It seems to me that you can not get rid of our natural "human centric " philosphy
The theory claims that all the observers are equivalent
If an astronaut travels at 99 % of the speed of light, from his point of view nothing changes

For him, time is still relevant as before, universe is still there as before

Dont forget that some galaxis travels , from our point of view ,at the speed close to the speed of the light

However when he comes back to earth he finds himself in the future

I think there is a constance for time compared to space. like how faster you go, the slower the slower time goes. If you travel 1 mile in one hour, this hour will take longer than the hour if you travel 100.000 miles per hour. So basicly there must be a constant between space and time. A number like pi, phi or all the other whatevertheycalledinenglish-constants.

Maybe I'm just talking nonsense here lol but ok... just my thought .

If two or more observers measure the same event they can get different values of distance and duration but a combination of these values is a constant for all the observers

yes, and what is this constant called?

The speed of light

Could the fact that time becoming irrelevant at the speed of light explain why a Creator could have no beginning nor an end?

why did edit?> i didnt insult anyone..I was merely pointing out the absurdity of this last comment.