This animated simulation shows the collision of two gold nuclei and the predicted results for the brief time following the collision. This is about the time needed for light to traverse the nucleus of a hydrogen atom. Time zero corresponds to the instant of collision of the gold nuclei. The simulation uses the parton cascade model of Klaus Kinder-Geiger, which is based on the theory of perturbative Quantum Chromodynamics. In the RHIC collider experiment two gold nuclei move toward each other at approximately the speed of light.
Relativistic contraction causes the gold nuclei to appear flattened.
At these ultra high energies the two gold nuclei see each other as consisting of quarks and gluons, not protons and neutrons. In this animation quarks are colored white and gluons are colored green. At time zero the quarks and gluons begin to scatter off each other forming a quark gluon plasma. Quarks and gluons can appear to move faster than light because of the uncertainty principle. The slower moving the particle, the more uncertain its position, thus it appears to move faster.