Sorry i didn’t realize it was factual questions.
It depends on which specific question is being asked. As @Chronos says, the Big Bang wasn’t an explosion in space. It was the creation of space and time for this universe. Not only that, but the universe is still expanding, equally in all directions as far as we can tell. So in a certain sense we are still in the Big Bang, since space is still being created, not stretched out.
Beyond that, we get into areas where we can speculate but have little to no evidence to come up with testable hypotheses. I have my personal beliefs, some of which have been mentioned earlier. Since the FQ of what we do know has been mostly answered, I’ll throw out my personal beliefs on the matter. Everything that follows is speculation.
I think the initial singularity was not infinitely small, but rather around the size of the Planck length. Yes; the implication is that our current universe is of finite size.
I’m in agreement with @Moriarty that our universe started off as a black hole in some other, possibly higher dimensional, universe. I think the reason the universe is still expanding is that the stuff getting sucked into the black hole in that other universe gets converted to dark energy in this one, which is why dark energy / the cosmological constant seems to not actually be a constant. It’s not a fundamental part of the universe, like the speed of light or conservation of momentum, but rather depends on how much stuff happens to be around in that other universe for our parent black hole to suck up at any given time.
Is this the same thing as the theory of eternal inflation?
That mysterious process of inflation and the Big Bang have convinced some researchers that multiple universes are possible, or even very likely. According to theoretical physicist Alexander Vilenkin of Tufts University in Massachusetts, inflation didn’t end everywhere at the same time. While it ended for everything that we can detect from Earth 13.8 billion years ago, cosmic inflation in fact continues in other places. This is called the theory of eternal inflation. And as inflation ends in a particular place, a new bubble universe forms, Vilenkin wrote for Scientific American in 2011.
In the recent “Extreme Physics “ issue of Scientific American, I read that space and time appear to have arisen from quantum mechanical entanglement.
So, the Universe is a black hole inside another universe? Does that make sense?
So black holes in our Universe are tiny universes, which each contain many black holes, which are tiny universes that each contain many black holes …
And out Universe is one of many black holes in a larger universe, which is in itself a black hole in an even larger universe, which is in itself …
Nope, not buying it.
I’ve been careful here to say things like “to the best of our knowledge”, and “the evidence suggests that”. There’s certainly a lot of room for our best models to be wrong. That said, there’s a difference between “there’s the possibility that our best models might nonetheless be wrong” and “nobody has a clue, so everyone just make up whatever sounds best to you”.
Eternal inflation is not the same thing as the Universe being a black hole in some other universe. In both of them, what we think of as “the Universe” is embedded in some much larger structure, but the nature of that larger structure and the phenomenon which caused the start of “our Universe” are very different in the two models.
And eternal inflation does certainly look plausible, and it gives different answers to many of the questions in this thread. In fact, it’s the main reason I’ve been including those weasel phrases like “to the best of our knowledge”.
Yes, that’s it.
I’m not claiming any evidence in support for it - I think it was a supposition concocted while under the influence of some form of hallucinogen.
But I provided some links upthread because I was pleasantly surprised to discover that other people, with some measure of scientific knowledge, have thought the same thing!
I, for one, believe that it is ludicrous to think that humans are alone in the universe. To the contrary, I suspect that existence is teeming with life. It’s not that far a leap to imagine multiple universes. I also like the idea that the elements which comprise known life are formed from stars. The whole black hole thing seems consistent with that - the ingredients for the universe derive from the collapse of a star.
As the above-mentioned astronomy teacher put it to me, we know the Universe is finite because it gets dark at night. If the Universe were infinitely vast and old, every point in the night sky would be occupied by visible starlight.
Olber’s Paradox:
I think the “standard” idea to explain that problem is the hypothesis of an infinitely large but finite in time universe. I don’t agree with the idea, in part because it seems to me that nature abhors infinities of all kinds, both large and small, but I accept that it seems to be the most popular hypothesis at this time.
How can you have infinite nothingness! 
One serious obstacle to black hole cosmology, nowadays, is dark energy. It’s difficult to even define concepts like black holes, or event horizons, in a context where dark energy is relevant.
Lee Smolin proposed an interesting variant called cosmological natural selection, in which there are numerous universes, and every black hole produces a child universe, but with slightly different fundamental physical constants. The cool thing about this model is it explains the anthropic principle: why the physical constants in our universe seem to be so finely tuned to produce life. They are, in fact, finely tuned to produce stars, and thus black holes, because in this model the universes which produce the most black holes will be the most common.
In other words, it’s (turtle-shaped?) universes all the way down.
Verrrry Interesting.
I’ve been chewing on this for a while. I really like it, but I don’t think I have the scientific knowledge to more fully flesh it out.
As I understand it, Einstein explained that space and time are linked. And so the idea that things are “moving” forward in time because of a gravitational force would seem to make sense.
It makes even more sense when you realize that, in General Relativity, there’s no such thing as gravitational force. Absent any other force, such as electromagnetism, everything just keeps on moving in a straight line. The presence of masses just changes what a “straight line” is, by virtue of curving spacetime.