Rock star physicist Brian Greene’s excitement was palpable at the Aspen Ideas signature event, Afternoon of Conversation.

What was he so fired up about? On Wednesday, July 4, the world will find out if scientists at CERN, the particle-collider in Geneva, have confirmed the existence of the elusive Higgs Particle, also nicknamed the “God Particle.”

[Update July 4: the Higgs Particle is no longer a theory!]

In this video, Greene gives an exciting, layman’s explanation of what the God Particle is, and perhaps more importantly, why we should care.

The feat of finding such a particle, he says, is akin to "trying to hear a tiny, delicate whisper over the massive thundering din of a NASCAR race."

Read more about the Higgs Particle or listen to this report on NPR.