There is (or, at least, there need be) no such thing as BEFORE time itself. The Big Bang was neither Big nor a Bang, and yet we have allowed the term of ridicule from a dour Yorkshireman who got it wrong to become the utterly misleading term of choice for the initial state of the universe.
I suggest a far less misleading term is timeless singularity. (or “near-singularity”, at least.) The initial state of the universe may be one of timelessness, such that the universe has effectively existed for ever.
Well,
either it was so probable an event that it couldn’t not happen
or there was something that ‘lit the fuse’.
The something could be something from “not the universe” or something within this universe that managed to go backwards in time as far as possible.
Yeah, but then these quantum cosmologists go and posit parallel branes, and stringy ultra-dense balls, or even totally flat, cold epochs that obviate Inflation, and simply require reconfiguration of a few variables through apparently spontaneous changes in state. I take this all to mean the universe (or multiverse, if you really want to get wild) could possibly evolve through multiple epochs, or cycle periodically from cold and empty to hot and dense, etc. Oh, and then some toss in this idea of a sort of less coherent state, from which what we experience as 3+1 spacetime spontaneously arises from a more versitile configuration of strings as a kind of emergent phenomenon.
These timeless, spaceless universes just boggle me completely. I can figure out how you can have spontaneous “changes” when there’s no time, or when time isn’t time but something else. How do you get change when there’s no way to talk about before and after? Well, apparently you can, though I am utterly lacking in the mental capacity to grasp it, even in a rudimentary fashion. I suppose these other possibilities make about as much sense to me as a “timeless singulatiry”, but suffice to say, people now dare to talk about physics “before” (whatever that really means) the event we call the “Big Bang”.
Or you could stop regarding it as an “event” and just take it for what it is: an inevitable singularity to which all infinite past-directed geodesics in a locally-Minkowskian 4-manifold must converge. It’s just geometry, not an explosion.
I share your confusion in many respects, Loopy, but there can be ‘change’ from a spatial viewpoint without time in the same way that a rainbow “changes from red to violet”, spatially and timelessly. In the same way, the initial state of the universe can represent a spatial “junction” with other branes or whatknot, and cycling from 1 to N dimensions can be thought of as being equivalent to cycling from red to violet.
Of course, ti may well be that we will never find much evidence for such a view of the initial state of the universe, and we must simply content ourselves that it is mathematically consistent. But the idea of dividing all that exists into the “timed” and the “timeless” is not new - indeed, it was cogitated upon by Thomas Aquinas in the 13th century. We might simply live in (one of) the regions of the universe where time exists.
It is a simple question, it just has a complex answer, like a lot of SD questions. In fact I might like to see them take this one on. As to the other stuff you asked afton I obviously don’t know.