system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who] Is it possible for the Doctor to travel back in time before the birth of the universe, or the Big Bang? What would happen?

I haven't watched Doctor Who in years, sorry if this is a stupid question. Just popped into my mind after watching a RealLifeLore video.
gpt
The Tenth Doctor once fought a being on a world inhabiting a black hole, who claimed to have been imprisoned there by an advanced civilization before the birth of the current universe.  The Doctor didn't believe it was true, and the demon could plausibly have been an unreliable narrator trying to make itself sound scary.

(Source: the episode, "The Satan Pit")