In conformal cyclic cosmology, there are no big bangs.
Once everything in the old universe has been reduced to photons, and all the black holes have evaporated, the universe loses its sense of scale, and resumes operation as a universe the size of a grapefruit (or the size of the earth - I don't think it matters).
I don't know how Penfold thinks this resizing is supposed to happen, for example whether it's instantaneous or a slow process.
I'd love to have a few beers with Penfold; a lot of what he thinks about isn't maths or cosmology, and isn't all fit for publication, but I imagine it must be very interesting.
Could it be we create and always have the big bang by blowing shit up in a particle accelerator, and that is the great filter not just for us, but the rest of the universe since it just starts over?
If so, then "first microsecond of the Big Bang" also doesn't make sense. And that may be the point of the above comment.
The only time reference is the one within the universe that is doing the banging, and within that universe, time has no beginning, right? Every microsecond has another microsecond before it.
Not really? It makes sense to ask what happens in the first minute of The Matrix film, but it doesn’t really make sense to ask what happened one minute before that. That particular domain (a specific film) has a pretty clear “beginning time” and apparently this model of the Universe does as well.
Have you seen Memento? It's a murder mystery that scrambles time. Much better than The Matrix.
There are two interwoven threads in the film, one in colour and the other in black-and-white. The B+W scenes are in chronological order, the colour scenes run backward in time. Colour and B+W scenes alternate. They meet up at the end - the murder scene, which in any sane movie would be near the beginning.
The protagonist has lost his memory, as a result of a bang on the head during the murder; he has no idea what happened "before the beginning".
There can be a point in time where you can't go further back - all directions point to the future - in the same way that there's a point on Earth where you can't go further North - all directions point South.
https://en.m.wikipedia.org/wiki/Conformal_cyclic_cosmology