TAKTAK is basing his theory on being able to travel faster than the speed of light, in essence
overtaking light emitted from your point of departure and then looking back to observe that light... in which, he's entirely correct that we cannot travel into the future or interacte with what we see...
In fact, we look back in time all the time, every time we look at the Sun as what we see is actually the Sun eight minutes ago, that ebing the time it takes light from the Sun to reach Earth.
The real question about time travel is if it is physically possible to transport material through time as we see in the movies.
Regardless of the myriad paradoxes this would throw up, it's not inconceivable that true time travel, such as we see on Doctor Who etc is possible, but it would take enormous resources to make even the simplest of 'time machines' work.
One good one is the wormhole time machine, which basically takes a wormhole and moves it to an appropriate
place in space, so when you enter the other end at the right moment, you emerge in the time and
space you wanted. The theroy is that wormholes emerge at a set time in the past, or perhaps generated their output at a point in time and are now moving forwards through time in pace with their surroundings... all you need to do is then move the end of the wormhole to where you want it to be when you emerge... a bit like moving the end of a hosepipe to fill a watering can.
But the resources needed to find and then move a wormhole would be enormous beyond belief... that's if we could even find one outside of theoretical physics, let alone manipulate one.
There's always the other option of harnessing tachyons and using or coupling them to have them drag us back through time... but seeing as these are again theoretical particles, it's improbable that we'll ever be able to build such a machine.
So, the answer is maybe... but not in our lifetime for sure.
But then again, maybe we have, in the future, been able to create a time machine and are right now tinkering with our own past?
It might explain why my cars keys keep moving... perhaps a benevolent relative a thousand years from now is delaying my getting in the car to avoid having a fatal crash? (Now
there's a thought to really mess with your head!)
And as a final thought, why I think we'll never see it in our lifetime? Cos we still can't agree what happens to a plane on a treadmill...