Matter in its present form was formed when our Universe emerged from the quark-gluon phase (QGP) at about 30mus into its evolution. To explore this early period in the laboratory, we study highly excited matter formed in relativistic heavy ion collision experiments: heavy nuclei crash into each other, and form compressed and energetically excited nuclear matter, resembling in its key features the stuff which filled the early Universe. In these experiments we further explore the physics of the vacuum structure of strongly interacting gauge theory, Quantum Chromodynamics (QCD). The common beginning for both, heavy ion collisions, and vacuum structure investigations, is the physics of the quantum electrodynamic (QED) vacuum in the presence of the supercritical external field that is formed when two highly charged heavy ions are brought together near to the Coulomb barrier in a considerably lower reaction energy collision.

15 pages, Dedicated to Prof. Walter Greiner on occasion of 70'th birthday, Prepared for International Symposium on Heavy Ion Physics 2006 (ISHIP 2006), Frankfurt, Germany, 3-6 Apr 2006. Published in Int.J.Mod.Phys.E16:813-828,2007