That cheeky imgur user has just reposted this article I read over a month ago
http://waitbutwhy.com/2014/05/fermi-paradox.htmlI thought it sounded familiar.
No, hang on, he has credited it as 'sauce' at the bottom.
Does make you wonder why we humans transmit so much radio noise out into the galaxy, and send out probes a la Voyager with precise data on our location and biophysical makeup.
I think its was Carl Sagan who pointed out that if you were to find yourself alone in the jungle, shouting out and drawing attention to yourself may not be the best survival strategy.
Wise words methinks.
If you liked that article try this one:
The AI Revolution: Road to Superintelligence – Why any aliens that do visit us are likely to be artificial, not biological. We may not be the king of our castle for very much longer…
http://waitbutwhy.com/2015/01/artificia ... ion-1.html 
Joe, interesting topic
