The comments on this particular video thread, as expected are spirited and inquisitive.

Commenter “David” has this opinion:

In order to travel to another time, past or future, that time must exist already, if it is future, or still exist, if it is past. Time travel thus requires that all moments of process or change or time co-exist eternally. For this to be true our universe would have to be something like a music file on a computer. Which might imply that the experiencer must be outside the computer. The time traveller or experiencer is able to drop into the file at any point and listen to the music; and can even listen to the music backwards. If this makes any sense to you, then you probably realise time travel is most likely not possible; at least from within the universe.

Commenter “Marozi” also has an interesting contribution:

The Grandfather Paradox is often brought forward as an argument against backwards time travel by notable Physicists such as Stephen Hawking. On the other side of the coin there are Physicists who entertain the concept of time travel as a genuine possibility like Carl Sagan – One mechanism to explain this is the Novikov Self-Consistency Principle developed by the Physicist Igor Novikov, which suggests that it would be impossible to create time paradoxes. Unfortunately it’s a field that I have no knowledge or familiarity with, but nonetheless fascinating stuff.

WHat do you think is Kip Thorne onto something or not?