Physics: At the Heart of Everything

sci-fact:

“ Long summers, mild winters, rich harvests, plentiful game—none of them lasts forever. It is beyond our powers to predict the future. Catastrophic events have a way of sneaking up on us, of catching us unaware. Your own life, or your band’s, or even your species’ might be owed to a restless few—drawn, by a craving they can hardly articulate or understand, to undiscovered lands and new worlds. ”
   _{~ Carl Sagan; (Shuttle Columbia Tragedy - 10 years ago today, February 1, 2003)}