The Relativistic Heavy Ion Collider (RHIC) experiment at the Brookhaven National Lab is designed to study how the universe came into being. It is believed that after the Big Bang, the universe expanded and cooled, consisting of a soup of quarks, glu-ons, electrons and neutrinos. As the temperature lowered, electrons combined with protons and formed neutral atoms. Later, clouds of atoms contracted into stars. In this paper, we describe how techniques of volume rendering and information visualization are used to visualize the large particle track data set generated from this high energy physics experiment. The system, called TrackVis, is based on our earlier work of VolVis - Volume Visualization software. Example images of real particle collision data are shown, which are helpful to physicists in investigating the behavior of strongly interacting matter at high energy density.