So, I have a simple question about these two. All matter can ultimately be broken down to energy, and then there's space-time. So are these two the only things that exist in our universe? Can either of them be broken down even further and if so, could they ultimately be interchangeable? And does space-time ever get "created"? From what I understand, before the big bang, space-time was so heavily bent that it was all contained within the singularity. And as the big bang happened, it expanded. So does this mean that new space-time was created, or it was just spread out after being condensed? If the former, was anything lost in the process? Is it possible matter/energy somehow had to be "sacrificed" and, by some strange means, converted into space-time? If the latter, how is condensed space-time different from that which is spread out? These questions may be invalid and/or not make sense, but I would appreciate any help. Thanks.