PHENIX is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons, and is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called quark–gluon plasma (QGP). Detecting and understanding the QGP allows us to understand better the universe in the moments after the Big Bang.