if you "travel back" in time,
you will not have the actual "past".

Because you have not been exactly there in the past.
So it is not your actual past, but some new state
that resembles your past.

There is simply no way to travel back in time.

Maybe some way to recreate a past state to a certain degree.
(like repositioning billiard-ball to a past position)
Even if everything looks like in the past, it is
not an actual tryvelling into the past.

Since in the past you did not know you where in the
future, you can never "BE" in the past with memories about
beeing in the future before.