[Serious] Is the Past Real?

[Jehanne]

If one could, even hypothetically, travel back to the past, then, the past must be real:

Loops in time

What about the past? This is where things get truly interesting. A black hole bends time so much that it can wrap back on itself.

Imagine taking a sheet of paper and joining the two ends to form a loop. That’s what a black hole seems to do to time. This creates a natural time machine. If you could somehow get onto the loop, which physicists call a closed timelike curve, you would find yourself on a trajectory through space that starts in the future and ends in the past.

Inside the loop, you would also find that cause and effect get hard to untangle. Things that are in the past cause things to happen in the future, which in turn cause things to happen in the past!

EarthSky -- Black holes are time machines, with a catch

Also seems to argue for the Many Worlds interpretation of Quantum Mechanics.