[neutralino]

Originally Posted by Profpat " However, this explosion was an explosion on the universe itself which created the universe (if that makes sense.) " This is probably a dumb question but is it possible that the universe imploded like a TV because of the vacuum? Best, Pat

It is beyond the realm of the big bang model to say what the actual big bang was, since the laws of physics, along with everything else, were created at the time of the big bang. So, basically, you can say whatever you like happened the actual moment of the birth of the universe, and no-one can argue against it. The only proviso is that the big bang created a universe that we see today (we mathematicians would say that they are the only "boundary conditions") but apart from that, anything goes.

An alternative way to think of the big bang is to not think of it as an explosion, but to think of it as a sudden appearance of space everywhere in the universe. This agrees with the normal point of view, that everything we can see now (everything within our horizon) was much more dense in the past than it is now, but it also gives us a way to imagine a big bang in an infinite universe: namely that is the universe is infinite now, then it was infinite at the time of the big bang.

Recently, there has been a model of the universe conjectured by some american cosmologists (/mathematicians) which uses the potential quantum gravity theory "loop quantum gravity." This is called the "big bounce" model. Basically, this is like a big bang/crunch universe (well, multiple universes after one another, since only one "cycle" can be called a universe). The previous universe is thought to have contracted to a very very small size until the forces of gravity are weak compared with quantum forces, and then the universe bounces back, and starts expanding again. This is quite an interesting model, although highly speculative, since in theory we would be able to turn time back beyond time zero. There has been talk of whether the previous universe would be identical to ours, but most people whos work I've read seem to think no, since quantum fluctuations are pretty random.

Anyway, that's quite a way off topic, so I'll leave it now, but I hope I've at least partially answered your question!