Yep the Big Bang is about that frame of time (because The Big Bang was the beginning of when time started) after that point when things began. We can now propose other ideas like a re-birthing universe or that this universe was born out of another universe or even multi-verses, however, the universe, it seems, is a closed system and therefore to think there is anything outside of it, before it, or indeed, after it, is a question of faith.
I am sceptical of any "scientific" theory that tries to explain something before the Big Bang. I think there comes a point that these people merely have to accept there was 'a' beginning. In fact, if they are honest, it is not 'a' beginning - it is 'the' beginning. That's my stance.
Physical science, by definition, is limited by the laws of the universe and those very laws are confined by the universe. There is matter and energy - that is it, and they exist because that's the way the universe is. Because it was so improbable that these constants work together, scientist propose an "infinite" solution, of sorts, to explain away the probability.
A non-eternal universe is an uncomfortable proposition, without some exercising of faith.







