JUST BEFORE THAT BIG BANG WENT KA-BOOM
Once upon a time, or was it in the beginning, there was a Big Bang and thus was born what we now call our expanding Universe - expanding because really Big Bangs are associated with explosive events and explosive events hurl out stuff hither and yon. But while there's little dispute about the Big Bang event, the central question is, was it an 'in the beginning' event, or more akin to a 'once upon a time' event? If the latter, then it's reasonable to suggest there was a prior existence to that 'once upon a time' event.
I've gone on and on about how there must have been a 'before-the-Big-Bang', that the Big Bang event 13.7 billion years ago wasn't the first cause. That's because no effect (in this case that Big Bang event) can be the cause of itself. Cause is external to, separate and apart, and prior to the effect. Now it's time to explore some actual before-the-Big-Bang scenarios even though there are still, even the majority, of cosmologists who suggest that speaking of a before-the-Big-Bang is akin to speaking of what's further down from the centre of the Earth, or what's north of the North Pole.
Astronomers can't see deeper into the history of our Universe than roughly 380,000 years after the Big Bang event. Until then, the entire Universe was still too opaque. It's like the Sun being too opaque such that we can't see beneath the visible surface all the way down to the core. So it's obvious that if astronomers can't see post the Big Bang to the tune of some 380,000 years on, they can't see before-the-Big-Bang. However, I'm quite certain there was a before-the-Big-Bang and that our Big Bang event was just one local cosmic pop in a cosmic ocean of bursting Champaign bubbles.
To understand the Big Bang event one needs to understand (as best as one can) what transpired just before the Big Bang event. And for reasons already outlined, what happened before exists in the realm of scientific speculation.
First cab off the rank, here's a brief explanation why there has to be a before-the-Big-Bang. The Big Bang event did not, could not, create time. Although astronomers suggest just that, when it comes to actually giving the recipe for cooking up a batch of time, our astronomical chefs' duck back into the pantry. So, IMHO, time already existed at the moment that the Big Bang went 'bang'. The Big Bang could only happen in time if time already existed, which means that time existed prior to the Big Bang in order for the Big Bang to 'bang' in or at the time it 'banged'.
As an aside, if our Big Bang wasn't a first cause, then one is hard pressed to say there ever was a first cause for reasons exactly similar to why our Big Bang wasn't the first cause. There always was a 'before' for whatever first cause you wish to postulate, therefore your first cause wasn't a first cause at all. The regression extends back infinitely. If the cosmos extends back infinitely, it stands equally to reason that the expanding cosmos will extend for all future infinity - for all eternity. As a theological aside, that eliminates the need for a creator god. It's been said before, but it bears repeating that if you have a timeless, existing for all eternity, creator God who created the Universe, why not eliminate the middleman (God) and postulate a timeless, existing for all eternity, Universe? By the way, a similar argument can be made for space. Anyway, back to the before-the-Big-Bang.
One aspect that's important from the get-go is that one needs to avoid the trap into thinking that the before-the-Big-Bang to Big Bang transition resulted in something quantum sized, like a singularity, at that point of inside-out transition. There just is no way IMHO one can take the contents of our entire Universe and squeeze that down into a size that would make a pinhead look massive in comparison. In addition, the laws of physics break down at such a scale since there is no adequate theory of quantum gravity. You'd require such a theory since 1) you're postulating a quantum sized object, and 2) because the entire Universe makes for a lot of gravity, that's a lot of gravity in an extremely tiny space. Since it can't be done (and thousands have tried to merge quantum physics with general relativity (gravity), it's best to bypass that can of worms entirely, if possible.
When you think of bangs today, big or otherwise, it's usually by something that's been sitting around for a spell just waiting for a triggering device like an about to be blown tire; about to be popped balloon; about to be exploded stick of dynamite, nuclear bomb, or supernova, etc. So, maybe our before-the-Big-Bang was akin to a giant firecracker just waiting for some before-the-Big-Bang happening to light the fuse. The one scenario that fits that bill is the Ekpyrotic Universe which basically states that there exists a minimum of two 3-D universes each existing in a higher dimensional space. That means the two universes don't actually see each other since photons can't pass through that higher dimension. However, gravity can pass through the higher dimension so the two universes can feel each other Thus, these two universes mutually attract under gravity, collide (our Big Bang and equally their Big Bang), and bounce apart - rebound. That process repeats at vastly lengthy intervals as gravity draws them together, again, and again and again (more Big Bangs) and then each rebounds, again and again and again.
The closest celestial firecracker we have is a supernova. Unfortunately, even the mother of all supernovas isn't quite in the same league as the Big Bang event. It's like pitting the Little Leagues against the Big Leagues.
A more theoretical firecracker might be the mother of all Black Holes which at some point reaches and exceeds bursting point vomiting out in reverse order its contents. That theoretical object is a White Hole, like perhaps a quasar (quasi-stellar object). Quasars spew out lots and lots and lots of stuff and energy all from a stellar-sized object. But that scenario too falls short of the amount of stuff comprising our Universe. It seems only the stuff of another universe could account for the amount of stuff that was 'created' to make our Universe. The one fly in the ointment here is that a singularity might lay at the heart and soul and centre of any proposed Black Hole and I wish to avoid that can of worms as noted above.
The other kind of 'bang' expansion is say, using as an analogy, traffic approaching and merging at a four-way intersection. That's the contraction bit. After the traffic lights change, the traffic is free to go on its way. That's the expansion bit. There's no real 'bang' per say. In other words, the Big Bang was the transition of space turning itself inside-out as it were. Either you had the collapse of a previous universe that went through that four-way intersection, or something akin, like a Black Hole that's vomited up its contents in the form of a White Hole, sort of like post Xmas sale shoppers rushing the external department store doors and then being 'vomited' out the inside of those department store doors and expanding into and throughout the store.
The more logical of the two scenarios is the latter. That's because we know that any universe is inherently unstable. You just can't have a perfectly still and static universe if for no other reason than gravity will pull all the flotsam and jetsam together, or in other words, a contracting universe is viable and likely.
The fly in that ointment is that the alternative, an ever expanding universe is also viable and likely if the oomph force that caused the initial expansion is stronger than gravity's grabbing force.
We can garner some insight as to whether the immediately pre-Big Bang era was hot or cold. If the Big Bang was an in-place explosion, well most explosions involve giving off heat, be it sodium placed in water (ka-boom), a firecracker (ka-boom), an atomic bomb (ka-boom) or a supernovae (ka-boom), these all appear to be exothermic reactions - they give off heat. However, an explosion in waiting is a much cooler state of affairs. While holding a firecracker in your hand won't burn your hand, the same cannot be said if it goes bang while you're holding it. So the pre-Big Bang era wasn't exactly hot stuff.
If the Big Bang was the result of a previous universe contracting, like cars approaching an intersection from all four directions, well the very act of compression heats things up. So, the Big Bang was a hot (time in the old town tonight) event, and therefore just before the Big Bang was also pretty heated.
Well, maybe we can't garner any insight after all since the era just before the Big Bang may have been hot or cold. But the Big Bang itself was a high temperature event no matter which way you slice and dice things which is good since that's what you'd expect from the observational evidence.
What about entropy? Our Big Bang Universe started off in a state of high temperature, a state of high order, or in other words low entropy and has been going downhill (cooling off) ever since. That is, the Universe is becoming more disordered as it heads towards an inevitable heat death. A heat death means that the entire Universe is now at the same temperature and no further cosmic evolution or change can happen. But if our Universe started off in a state of high order, then the pre-Big Bang phase must have been in a state of high order too. Well, high order would have been the order of the day in either of the two pre-Big Bang scenarios.
