Doug_E_Fresh said:
@Village
I'd like to know what you think about the science related to the idea of the universe having some point of beginning of existence. What are your thoughts on that? Do you think that it did have a beginning? or has it always been (eternal)?
I think it's a fascinating subject. I'm not an expert in the field (my speciality is biology, not physics), but from what I've read the science regarding the early universe seems to be pretty sound. Certainly the evidence for the curved nature of four dimensional spacetime on which it hinges is pretty solid.
At the moment (as far as I know - as I say, I'm no expert) there seem to be three contenders for what happened before then...
1) Standard "Big Bang" singularity model. Our four dimensional spacetime is curved, and that curvature gets more pronounced as we move back in time. At some point, the curvature gets infinite and we can go back no further. This point of infinite curvature is the singularity. It's kind of the "beginning" of the universe, but the reason I used quotes around that is because a beginning implies a kind of linear time where there is time before the thing begins and time after it has begun. But with curved spacetime that's not the case, because time is a dimension within the curved universe that measures the position of events within it, not something that can be applied to the universe itself. The best analogy is to think of the Earth. Wherever you're standing on the Earth you can travel north or south. Think of travelling north as going forward in time and travelling south as going backward in time. We can keep going south until we reach the South Pole but can then go no further. Whichever direction we go from there is north. By definition there is nothing south of the South Pole - but this isn't a paradox, it's just because of the curved nature of the Earth's surface. Asking what is south of the South Pole is meaningless. According to this theory, the universe is similar. You can keep going back in time until you get to the singularity, and wherever in the universe you started from you'll end up there. But from there, all directions in spacetime lead to it's future just like all directions from the South Pole lead north. So asking what happened before the beginning of the universe is like asking what is south of the South Pole. The question is meaningless. This is the most prominent scientific model for the beginning of the universe, and it fits the maths, but there are some observations that have been made that - while they don't actually contradict this model- the model doesn't explain.
2) M-Brane model. This more recent theory postulates that our four dimensional spacetime is a bubble that has budded off a larger multidimensional spacetime. If this is true, it means that our universe isn't the only one that exists - there are others too. Our universe therefore had a definite beginning. Whether the multidimensional spacetime that contains our universe also had a "beginning" (or whether such a thing is even a meaningful thing to ask given its nature) is a complete unknown. So far, the mathematics of M-Brane theory seems to work out, but we've not yet found any evidence to either prove it right or prove it wrong.
3) This one is an alternative to the standard model that relies on Loop Quantum Gravity - something I don't even pretend to understand. From what I've read about it, it's quite different to the standard model although the results are very similar (which they would have to be, of course - all models have to have results that are similar enough to match what we observe!) The key difference is that in this model there is no singularity at the start of the universe. Instead, the universe is cyclical with an infinite number of "Big Bangs" and "Big Crunches".
So to relate these to your question, each of these has a different answer:
1) Time is a property within the universe, not of the universe. Therefore it's meaningless to describe the universe as having "begun" at some point in time.
2) The universe is part of something bigger. Our universe itself is one of many and it had a beginning, but we don't know enough about the "something bigger" to make definite pronouncements about that.
3) The universe is eternal and has no beginning. However, given its cyclic nature, we can treat the beginning of our current cycle as the "beginning" of the universe.
As for which of those three models is closest to the truth, I've no idea. I kind of lean towards preferring the M-Brane model, but that's only for aesthetic reasons. I don't claim to be a good enough cosmologist to argue the relative merits of the three.