Theoretically, how can time travel be at all possible?

Yes, it is possible. Not only that, it happens more than you think, but you just don't know it, even when you travel in time. But you can only travel forward in time, never backwards. The paradox prevents backwards time travel (if you go back in time and kill your grandfather before he meets your grandmother, you would never be born, which means you can never go back in time to kill your grandfather, which means you are born and go back in time to kill your grandfather).

The video below has a pretty good description about time travel, and demonstrates it with the "light clock experiment".

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https://youtu.be/-O8lBIcHre0

It's different to travel to the future than to the past. If you want to travel to the future you should go to a really heavy planet/star or a black hole and when you go back to earth you'd have traveled to the future. Traveling to the past is more complicated, you can't travel to the past in this universe, you need to travel to a parallel universe.

Try Alcubiere drive. one is making it on Earth. Locate your own source & supplier.

All that can happen is time can be slowed down - the closer to the speed of light a space ship will get -

there is no theory. our current understanding of how the universe works does not allow for time travel.

My advice is - don't think of time travel as requiring a device to achieve.

What is time?

One definition would be - that it's the chronological ordering of events. Physicists refer to time as being the number of vibrations of a cesium atom per 'n' amount of time. Most normal people refer to it as the diurnal cycle. Precision is generally unnecessary.

The simple fact of the matter is - for this - and many other aspects, it's a chronological ordering of events which are both measurable and repeatable. Why measurable? Simple: You know one day is equivalent to someone else's day. Why repeatable? Consistency. Predictability. Etc.

Can you, in theory, repeat a sequence of events?

With simulations, I think you'd be tough pressed to find anyone on Earth naive enough not to believe you can't repeat events with the proper simulation. If Game Designers would focus more on historical simulations of 'the boring times of history rather than the infrequent warfare that erupted in isolated parts of the world, we might have some incredibly immersive cities and worlds.

And with incredibly accurate written and physical records dating back to the 1700s, wouldn't this be a form of time travel? Especially if you put an Oculus VR on and could stand in a fully realistic depiction of London in say 1776 to see history unveil from their perspective?

Keep in mind one simple equation: E=MC^2. Put in layman's terms - anything is possible.

So as we 'simulate' the worlds of yesteryear and the future, particularly with immersive simulation, are we not - in a way - 'time traveling'?

I know the argument against this. I was the argument against this.

How do we know that's what really happened.

I'll answer this as simply as I possibly can.

Reality is the canvas. The story I tell is the paint, and I, as the artist, am the key to the story being told.

Time is nothing more than the cumulative of all stories told thus far.

And those that have yet to be told.

Like how time travel is not just possible, but has been used to paint the world I experience around me every day.

As Doctor Who once said. "The story is the greatest weapon ever invented".

Yes, my Dear Doctor, but after you got done using it as a weapon, I realized its true potential was far more than a warrior with a club mentality could ever imagine.

That's why we see UFOs... the "us" from the future go back in their past - which means they're sitting in outer space... then, they have to fly back to where Earth was in their past.
Which explains the 1947 Roswell incident - the crash was caused by human error. Just... humans from the future.

There is no theory for time travel.

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