interesting overview http://www.science.psu.edu/alert/frontiers/AshtekarHandout2-2004.pdf Pen state lectures feb 2004 Abhay Ashtekar. QUOTE. "there was no emergence of the universe from nothing because nothing simply does not exist". "radiation or matter can transform into geometry and vice versa". "geometry is physical, it is so similar to matter that it can change itself into matter".