Let us address the mystical and mind-boggling question rationally.
Even the most intelligent brains across the world have intensively probed into it without arriving at any definite conclusion.
Even so-called Einstein of the day Stephen Hawking was also seized with the topic. I have watched some of his TV programmes and found his conclusions sometimes absurd, sometimes inexplicable ( I am not challenging his infinite IQ ! ). He also talks about some weird time-machine that can take you into your past… yet another silly western fantasy !!
The question was most rationally answered by Maharsi Patanjali in his exposition on Astangayoga thousands of years ago.
All events of past remain embedded in the domain of consciousness, known as Smriti.
When Sadhana is successful after so many years / births / lives of spiritual pursuits, one is able to penetrate into any Smriti of his / her choice and be in that era / time-zone as long as he / she wishes to.
Certainly, ultimate liberation demands dissolution of all Smriti-s.
That is the right way to re-visit your past in true sense of the term. Then the past becomes ENTIRELY PRESENT !!
Past CANNOT be re-visited by loading yourself onto a Time-Machine. Past is always SUBTLE, can be re-visited ONLY through subtle means. Gross means can NEVER take you into your past lying in the subtle universe, on subtler planes of consciousness.
Only if somebody could explain this REALITY to Stephen Hawking….