ROBERT WILL BE IN CHAT DURING PREMIERE TO ANSWER YOUR QUESTIONS! Dark matter is mysterious stuff that affects the motions of galaxies, inside and out. But we can't see dark matter at all. It does not absorb, reflect, or emit light; in short, it's dark. And it's a big deal, since it constitutes 85% of the mass in the universe. Robert McGehee, a PhD scholar in Physics at UC Berkeley, and soon to be a Leinweber Postdoctoral Research Fellow at the University of Michigan, will illuminate dark matter for us by describing the ingenious methods scientists are using to search for it.