Time as we know it started at the big bang. This only means that its as farback as we can go and still have data.

That is the absolute time.

I for one believe in an oscolating theory of the universe, where it expands and contracts. If this is the case, then the space was always there, there were just no...or very few particles.

Is there any real way for us to know how much mass is needed to be completely condensed in order for it to have a huge explosion? You could say all the mass in the universe. But that begs the question...would there have ever been a big bang if there was just that much less mass. And if there was more mass...then the entire mass explosion would be variable on something else.

If a type 1A supernova always explodes with the same amount of mass...every time...then could you not speculate that a huge amount of mass would explode with the same amount of mass as well?