[Snapolit1]

My son in an astrophysicist, and that stuff is waaaay beyond my brain power. But I think it's a given at this point with quantum physics that there are realms of the galaxy that currently exist in periods of time that happened long ago and far away, so there are definitely different past, presents and futures out there.

Originally Posted by Mark17

I don't know if it is physically possible (not for 21st century people, but by the laws of advanced physics) to travel backwards in time, but consider this:

Not saying anyone has to travel backwards in time, but if it is somehow possible, that would mean, every detail of the past must somehow be preserved, or the information must be retained for the past to be re-constituted.

If, somehow, time could revert to, say, 1912, then the information for every detail from that period must be able to be re-accessed. Put another way, Joe Wood and his blazing fastball still exists.

Again, even if nobody or nothing ever returns to that time, if it's within the realm of possibility, then by definition the past still exists.