I don't think it would ever reach a "critical mass" but rather a critical energy level relative to its mass. In other words it would gain so much energy that it's gravitational bonds can no longer contain it in one peice. The energy would be coming from the vacuum fluctuation that formed around it because of the extremely powerful gravitational pull.<br /><br />The theories on it are only my own. So, no there aren't any theories (that I know about) on it from a source that has known credibility to you.<br /><br />Although, I've already done more reading and have revised my thoughts and theory because I see how it's not possible. <br /><br />I don't see how we could be here without the known universe coming out of nothing. So there should be some way to do the magic trick of making something appear out of nothing. That's a puzzle that I have been trying to solve. Vacuum fluctuations sounded like they could be the thing i was looking for. There would have to be a way for a vacuum fluctuation to happen without anything to supply it power, and without any external forces acting upon it. Maybe there are different types of vacuum fluctuations... Maybe the background microwave radiation is preventing these anomalies from occuring around us so we can't observe them... <br /><br />Adding onto what I said before about the "critical energy level relative to its mass," Maybe it's gravity would smash the atoms that make up the mass and convert it into energy. Then, after enough atoms were smashed and converted to energy, it would begin to swell untill it finally converted enough mass into energy that it just explodes (I guess this could be considered critical mass too if you think about it). Also, maybe the reason why we can't see outside of our own explosion (or universe, whatever you want to call it) is because it sent out a radiation shockwave that deflected all the light from other explosions (or universes, whatever...) from getting to us.... What do you think?<br /><br />Please add y