(Photo: Claudia Marcelloni, © CERN)

The Large Hadron Collider (above), the world's largest particle accelerator, struck fear in the hearts of some who believed it was capable of creating a black hole strong enough to destroy the earth a couple of weeks ago when the switch was flipped for the first time.  You're reading this, so let's assume the earth as we know it still exists, shall we? 

But what IS a black hole?  Should we be scared? NOVA addresses these questions in "Monster of the Milky Way" Tuesday at 8pm on WTCI.  The program is an examination of black holes, what they are, and their role in the life and death of galaxies. It also details the work of a team led by UCLA astrophysicist Andrea M. Ghez to prove that a black hole exists at the center of the Milky Way.