http://waitbutwhy.com/2014/05/fermi-paradox.html

Some disturbing food for thought on the continued silence of the night sky.  Well, I suppose it’s not all disturbing.  Just a few of the concepts, such as the one where the possible Great Filter is actually ahead of us and we have an infinitesimally small chance of proceeding into the wider universe.  Actually, come to think of it, the concept about possible predator civilizations lurking out in the stars cutting off attempts at proceeding outward into the galaxy is the cause of more of my sleepless nights, likely because I played Star Control 2 at a very impressionable age.  The idea is outlined rather well in the Wait But Why link, but I think it’s summed up best by the following passage from The Killing Star, by Charles Pellegrino and George Zebrowski:

Imagine yourself taking a stroll through Manhattan, somewhere north of 68th street, deep inside Central Park, late at night. It would be nice to meet someone friendly, but you know that the park is dangerous at night. That’s when the monsters come out. There’s always a strong undercurrent of drug dealings, muggings, and occasional homicides.

It is not easy to distinguish the good guys from the bad guys. They dress alike, and the weapons are concealed. The only difference is intent, and you can’t read minds.

Stay in the dark long enough and you may hear an occasional distance shriek or blunder across a body.

How do you survive the night? The last thing you want to do is shout, “I’m here!” The next to last thing you want to do is reply to someone who shouts, “I’m a friend!”

What you would like to do is find a policeman, or get out of the park. But you don’t want to make noise or move towards a light where you might be spotted, and it is difficult to find either a policeman or your way out without making yourself known. Your safest option is to hunker down and wait for daylight, then safely walk out.

There are, of course, a few obvious differences between Central Park and the universe.

There is no policeman.

There is no way out.

And the night never ends.

That’s the sort of cheery, smiling bit of thought-experiment that I’m always on the lookout for.