posted on May, 25 2008 @ 06:22 AM
Technological intelligence should be common. Us humans seem to have arisen naturally on this planet via evolution. Its taken a while but given the age
of the galaxy there should be many many civilizations alot of them far more advanced than us.
The hole in the theory is when we look into space we see no signs of it. what would we expect to see if tech intelligence is common?
1. In theory we should be swarmed by interstellar probes sent by the civilizations throughout the galaxy. A self replicating probe travelling at
1/10th the speed of light would need only 40 million years to populate evry star system in the galaxy. There could be civs up to 3 billion years older
than us plenty of time to get the job done. But we havnt found any yet.
2. The earth has never been colonized by E.Ts, its had a nice oxygen atmosphere for 500 million years and we wernt around stop anyone. Yet nobody
seems to want to stay here.
3. Signals of some form would be another obvious sign. An advanced civ could build a beacon so powerfull it could be visible with the naked eye from
the surface of earth (naked eye SETI). Or an extremely powerfull radio signal again we dont see any of these.
The great filter is a way of explaining the silence. Its the reason our theory doesnt match our observations. Something is filtering out the
civilizations in the galaxy and stopping them doing these things.
Some people think the great filter is complex life itself is extremely rare. If plants and animals are rare it follows any higher intelligence will
also be rare.
Others say the filter lies ahead of mankind. That its common for civs to reach our level but they all destroy themselves somehow. An unknown future
technology is a prime candidate. Everytime a civ discovers this technology it ends up destroying them.
Maybe there is no "great filter" many civs do exist but they dont do things like send out probes , colonize planets or make giant beacons. Or we
just havnt looked hard enough yet.
So great filter or not? and what do you think it could be?
p.s heres a nice short sci-fi story about alien probes being discovered in our solar system www.davidbrin.com...
[edit on 25-5-2008 by yeti101]