http://blogs.discovermagazine.com/badastronomy/2007/07/01/what-happened-before-the-big-bang/
Woah, it looks like the actual science is advancing on this subject. See, that's the cool thing about science, they don't stop trying just because they reach a tough a spot.
The not yet complete theory proposed in this article just raises more questions. In, fact in raises questions about another universe.
A particular problem is that of entropy. For the previous universe to have have collapsed, it's entropy would had to approach an absolute minimum. For our universe as we approach t=0 we approach infinite density and temperature at a finite point in time (yes, the article points this out). We have observed that our universe expanded from the infinite density and temperature to where we are today, and as the expansion continues entropy approaches a maximum limit. So basically entropy goes from 0 to positive infinity for our universe as we know it. If the proposed new theory is assuming that the previous universe is a somewhat backwards model of our universe, it still doesn't explain what happens at t=0 or t=infinity, it just shows that at that time the rules of the current model no longer apply.
Our current universe model will eventually become too cool to sustain life because it expands forever. So this gives us only a few options. 1) something we have no idea about happens at t=infinity in order to to reverse the process back toward the minimum of entropy. 2) the previous universe has completely different constraints (volume? mass? energy? limits of entropy?). 3) our current model is farther off then what we think. Either way this new theory just raises more questions ,could be good, could be bad.
The reason it could be bad is that our model may become skewed because we don't have enough info. And, we may never have enough info. For the theory of relativity to work light must travel at a finite rate. This means the light from things that have already happened an extremely long time ago may never reach us. Inflationary theory attempts to resolve this but by assuming that the bounds of the observable universe expand faster than the universe itself. We have not been able to verify this, and if inflationary theory is correct, it still means there is a limited range of the universe we can see.
It will be interesting to see how small or big of a step this proposed new theory actually is.