Its a matter of 64 years,  at the close of WW2  since  a few Norwegian Radio Astronomers, first encountered  the CBR.   Continuous searches for intelligent have yeilded nothing. 

One possible  reason that we are alone, at  least in the home Galaxy  is the fine balance of conditions neccessary to support life.  Therefore   any major imbalance may preclude  its development. 
Such a factor is  the inclination of the Solar Core to the ecliptical that generates   the massive twin spirals inside  the Sun.  In the event that   a Sun like star existed, but  failed   to pass the 7 degree ecliptical
condition,  then the  star  in question would be of "oblate" configuration,    and  a planet sinilar to Earth, in a similar orbit , would possess a disproportionately  high temperature.

Kevin Wilson