"It is the nature of intelligent life to destroy itself" <--my favorite explanation of the Fermi Paradox, in the process of being demonstrated on a planet near you!
WHAT IF SUPERNOVAE AREN'T SUPERNOVAE? WHAT IF THEY'RE THE REMNANTS OF AN ADVANCED CIVILIZATION THAT BLEW ITSELF UP BECAUSE IT GOT THE MATH WRONG TRYING TO HARVEST ENERGY FROM THEIR SUN? A "STELLAR CHERNOBYL" IF YOU WILL. HOW MANY NOW EXTINCT CIVILIZATIONS WOULD THAT BE?