posted on Sep, 29 2014 @ 02:55 AM
1) there aren't any
2) they're too far away to notice us
3) they're way too different to relate to us (real aliens would be unlikely to be bilaterally symmetric bipeds)
4) the galaxy's too young for any species to have evolved to the point where they are extensively using 'warp drive'.
5) most alien species aren't acquisitive, or inquisitive
6) Greg Bear's hypothesis: if you start doing a lot of broadcasting and it's noticed, older very paranoid civilizations drop by and kill you before
you become a threat
7) Tom Bedlam's hypothesis: about the time you figure out 'warp drive' and develop the technological infrastructure to support it, you discover
metric engineering in the large, find that there's that little teaser of infinite energy, and you test it out, thus becoming the next mysterious
8) you discover "warp drive", go visit a nearby planet or two, and bring back something that destroys your ecosystem. Ta-ta.
9) most any civilization that discovers warp drive finds a nearby civilization that is about their own level. And since it's nearly impossible to
communicate with them, both think the other is a deadly danger and they lay off each other's planets and reduce them to gamma-irradiated rubble in a
10) one faction on a planet gets there first. So, once the others find out your nation/city-state/hive has warp drive, the others bomb the entire
planet into oblivion out of fear/envy etc.