There have been some speculations as to what happened before the Planck Era. I will now go over two models and point out that they raise some interesting questions about time.

Model one: Our universe created ex nihlo

Basically the theory that 'nothing' is unstable and hence quantum tunneled into space-time/physics laws. If this caused the Big Bang, it happened about 13.7 billion years ago. Yet, what was before that? How do we define time? If space is required for time, why would it take a perhaps infinite amount of time to quantum tunnel? I say infinite, since there is no way to measure time before this state. (since there was no space-time)

Model two: Multiverse budding

This assumes the multiverse is eternal, basically quantum events led to the 'budding' off of our universe from some mother universe. This would explain time, since the space-time is from the mother universe, but what about our time? Did an infinite amount of time (since the mother universe is eternal) pass before our creation? How is that possible?

I have no idea why, but I thought of these questions while walking around campus and just couldn't figure them out.