How did the universe expand faster than the speed of light?
That's the inflation bit at the very start of the expansion, I don't think the scientists really know how it all works under those extreme conditions, same as the singularity of a black hole regular physics falls to bits. That's partly why they are so excited by this, it could just be a hint of how Gravity fits together with the other three forces and also how quantum physics relates to large scale effects. I read loads of books and am very interested in cosmology and all that, but I don't pretend to understand it much.
Desp