There's been a lot of talk about this new paper which uses loop quantum gravity to try and explain what happened before the Big Bang. Unfortunately, I can't give any real input on this subject, because I don't really know that much about it. But here's the general idea which has been come up with:
Quantum-gravity theory indicates that the fabric of space-time has an "atomic" geometry that is woven with one-dimensional quantum threads. This fabric tears violently under the extreme conditions dominated by quantum physics near the Big Bounce, causing gravity to become strongly repulsive so that, instead of vanishing into infinity as predicted by Einstein's Theory of General Relativity, the universe rebounded in the Big Bounce that gave birth to our expanding universe. The theory reveals a contracting universe before the Big Bounce, with space-time geometry that otherwise was similar to that of our universe today.It's basically saying that we now have a theory which predicts how our universe came into being. Of course, this is the idea of a cyclical universe, one that expands then contracts then expands again. But the helpful thing about this new work is (I think) that it gives a mechanism. Loop Quantum Gravity describes WHY the universe bounces. Apparently, at the extremely high density and pressure of the Big Bang, gravity actually repelled, thus giving birth to the expanding universe we see today. Of course, there are much more qualified minds that talk about this. Here is the Bad Astronomer's take on it. And here's the Space.com article on it. Enjoy!
Oh! I almost forgot! And TAKE THAT String theory! Your monopoly on theoretical physics resources will soon start to decay like miniature black holes(?!)