The Great Filter - is there one & what is it?

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]

Intelligent life doesn't mean the best.

The little microbes on Earth that are ever changing and mutating are probably the reason why an alien life, if within traveling distance, could not set up colonies. The moment they land and take a wiff of our oxygen, they would be infected by a million viruses and bacteria. With no evolved immunity, they will die horribly.

Even robotic probes would not be immune. Rust, critters, lightning, earth magnetics, bad luck and other things would play havoc even with the most advanced materials.

As for radio signals, the milky way is 100k light years across. There are probably a million things within the galaxy that will interfere and distort those radio waves.

Its not that I don't believe that alien visits are possible or have happened. I believe that the earth's biology is the reason why aliens seem to be at arms length. They have very good reason to be careful.

I like the premis, but by your own standards, we have not achieved intelligent life here.

We have not launched self replicating probes. The technology is beyond us until we can produce miniaturized refining and manufacturing plants in space. The majority of the probe you spoke of would be these plants.

We do not have a great beacon.

So by your own standards, there is zero known intelligent life in the universe, including us. There is no known Easter Bunny, no known Santa Clause, No known intelligent life. I hope you appreciate this alternative hypothesis, unfiltered.

If I were intelligent life in the universe I would take a good look at what lives on this planet, and what it does. The I would do everything I could to keep humanity contained and unaware of my existance.

reply to post by Cyberbian


we are a very young emerging civilization at the very beginning of technological intelligence . 100 years is nothing in cosmic terms imagione what we could do in say 1000 years or 1 million years. If intelligent life is common there should be civilizations upt o 3 billion years older than us.

If the probes are self replicating they will never "die" just keep making new copies of themselves. Even if the civilization itslef dies out the probes should still be going.

We have seen no beacons so if intelligence is common that means evry single civ has not made one. If you think intelligent life is common that means every civ for the last 3 billion years hasnt done it. Youd think from millions of civs there should at least be 1 beacon.

Theres only 2 answers that satisfy me.

1. all tech civilizations destroy themselves before they can do such things as probes, colonize or beacons

2. Tech civilizations are extremely rare

[edit on 31-5-2008 by yeti101]

Originally posted by Cyberbian


We do not have a great beacon.

I would disagree we have been spewing out raw Radio and Television signals for years if they are in range they see us

A question here.. if we were to visit an alien world.. How would our Immune systems react to alien Bacteria,Viruses,Spores,Fungi?

[edit on 31-5-2008 by Lantian]

reply to post by Lantian



yes this is a good reason why colonization has never happened. Although theres nothing stopping them building habitats just like we would do on the moon or mars. The advantage of a planet like earth is it gives great protection from natural dangers like meteors.

theres still the lack of robotic activity in our solar system to explain. maybe they are there but yet to be discovered.

slayer69, Radio/tv is quite weak, im talking about a beacon visible with the naked eye from the surface of earth. A blinking star or some other massive obvious sign . Although you are right- our radio signals give our presence away to anyone whos in range and with the tech to detect them

maybe when our signals reach another civilization they will invade & destroy us. Could be tomorrow or maybe in 10,000 years , perhaps humanity has already sealed its fate and theres nothing we can do about it.


[edit on 31-5-2008 by yeti101]

Originally posted by Lantian
A question here.. if we were to visit an alien world.. How would our Immune systems react to alien Bacteria,Viruses,Spores,Fungi?

[edit on 31-5-2008 by Lantian]

I would to follow this question with another. IF aliens exist what makes us think that they would be affected by our bacteria, viruses, spores, and fungi? I mean if they're truly alien then their systems wouldnt be anything that our diseases would recognize. The same as we dont get diseases from certain species and vice-versa. They would possibley have a different cellular structure and different protiens...

Originally posted by yeti101
reply to post by Lantian

 

maybe when our signals reach another civilization they will invade & destroy us. Could be tomorrow or maybe in 10,000 years , perhaps humanity has already sealed its fate and theres nothing we can do about it.


[edit on 31-5-2008 by yeti101]

Considering one of the first broadcasts that they would see is Hitler, I almost expect them to come destroy us.

[edit on 29-7-2008 by XTexan]