Drake equation and lifetime of intelligent civilizations

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Message 237130 - Posted: 25 Jan 2006, 0:29:29 UTC

One of the difficulties for communicating with (supposed) extra-terrestrial civilizations is that the personal lifetime of a human being is rather short compared to the time that light/radiowaves need to travel to other stars, which may take several thousand years. Or, speaking of societies rather than individuals, the expected lifespan of an "intelligent" civilization may be only some decades or centuries under pessimistic assumptions. This is one of the most uncertain and limiting factors in the Drake equation.
The situation would be quite different if the lifetime of intelligent beings would be much longer, say, some 10,000 or 100,000 years. While no intelligent lifeforms on Earth have such long lifetimes, couldn´t we image that extraterrestrial lifeforms had a very different life cycle? This does not exclude the possibility of self-destruction of such a civilization, but its life in general could be much slower compared to ours, thereby giving them more time to wait for interstellar communication. Are there any reasons that intelligent lifeforms are limited to a life-cycle on scales of decades? For instance, if temperatures are cooler, chemical processes are slower, and life in general is much slower (as can be seen from a comparison between polar and tropical regions on Earth). Another point is that the life cycles on Earth are to a considerable degree synchronized with the annual cycle, as can be seen in the breeding seasons of many animals. How would life evolve on a planet where one annual cycle took a hundred terrestrial years? My question is whether our problem, that the human life is short compared to the required time for interstellar communication, is just due to the specific, local environment constellation on our planet, or whether it is supposedly a general phenomenon that other civilizations encounter as well.
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Message 237238 - Posted: 25 Jan 2006, 4:13:51 UTC - in response to Message 237130.  
Last modified: 25 Jan 2006, 4:14:35 UTC

One of the difficulties for communicating with (supposed) extra-terrestrial civilizations is that the personal lifetime of a human being is rather short compared to the time that light/radiowaves need to travel to other stars, which may take several thousand years. Or, speaking of societies rather than individuals, the expected lifespan of an "intelligent" civilization may be only some decades or centuries under pessimistic assumptions. This is one of the most uncertain and limiting factors in the Drake equation.
The situation would be quite different if the lifetime of intelligent beings would be much longer, say, some 10,000 or 100,000 years. While no intelligent lifeforms on Earth have such long lifetimes, couldn´t we image that extraterrestrial lifeforms had a very different life cycle? This does not exclude the possibility of self-destruction of such a civilization, but its life in general could be much slower compared to ours, thereby giving them more time to wait for interstellar communication. Are there any reasons that intelligent lifeforms are limited to a life-cycle on scales of decades? For instance, if temperatures are cooler, chemical processes are slower, and life in general is much slower (as can be seen from a comparison between polar and tropical regions on Earth). Another point is that the life cycles on Earth are to a considerable degree synchronized with the annual cycle, as can be seen in the breeding seasons of many animals. How would life evolve on a planet where one annual cycle took a hundred terrestrial years? My question is whether our problem, that the human life is short compared to the required time for interstellar communication, is just due to the specific, local environment constellation on our planet, or whether it is supposedly a general phenomenon that other civilizations encounter as well.



First, here is another on topic post from not to long ago: Seti@home and the Drake equation.

The thing that limits our lifetime is the protein clocks on our DNA which tells it to stop replicating after x number of times, then we start dying after a certain point is past. This is a random feature of nature possibly evolved to limit lifespan to maximize diversities in various situations. So, yes there could easily be lifeforms living hundreds of years instead of 10s of years.


I think that the biggest limiting factor is the lifetimes of suns. If we want to live, we'll probably need to get off the planet and learn to live without our sun specifically because it's burning out. What do we have? 6.5 million years left? We just got off the planet after 4.5 million years. But the earth might move out of a reasonable distance from the sun by then. We might be able to get Venus up and running, it is about a magnitude of 10 smaller and the gravity is around 90% of our gravity at the surface. The drawback is the no water and high density atmosphere which the earth had early in its life. If you add the 10% in water after it cools down a bit after it moves away a bit or when the sun begins to cool, the water and pressure would be good for simple organisms to breed and begin incorporating some of the N2 into organic matter and for the water to dissolve some of the atomosphere. Of course, you'd need a moon soon after to help create geological events beneath the surface to cause land masses to appear above the water.

The point is that you're right. There are options. I don't like the drake equation since I don't believe in the big bang. Time is not limited to the "age of the big bang" but has had an eternity for life to form and we are not the first by any means.

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Message 237578 - Posted: 26 Jan 2006, 1:02:25 UTC

I may be misinformed but I thought our sun had about 5 billion years to go, or did you mean we have about 6.5 million years until the earth gets too far away from the sun to be viable?
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Message 237586 - Posted: 26 Jan 2006, 1:30:41 UTC

It is worded weird which is a problem I have. We got of the planet after 4.5 billion years. By this I mean we first launched an astronaut into space when our sun was/is about 4.5 billion years ago. With the estimated lifetime of our sun set at about 11 billion years, we have 6.5 billion years left to learn to live without it. Oops, i said million when I should have said billion. Your right.

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Message 237976 - Posted: 26 Jan 2006, 22:51:24 UTC - in response to Message 237238.  

I don't like the drake equation since I don't believe in the big bang. Time is not limited to the "age of the big bang" but has had an eternity for life to form and we are not the first by any means.

To my current understanding, the Drake equation is not based on the assumption of a big bang. What enters the Drake equation is the assumption that the lifetime of an intelligent civilization is limited, as is the lifetime of a star. Interstellar two-way communication is only possible if the lifetimes of two intelligent civilizations overlap, so the shorter the lifetime of a civilization, the smaller the chance that we can communicate with them during our own civilization lifetime. This general idea is the same for an expanding universe originating from some sort of Big Bang, or for a steady-state universe, or probably a universe with a different life cycle. For the current civilization on Earth, the limiting factors for doing interstellar communications is, supposedly, the rather short lifetime of a human being compared to some thousand years that the light needs for interstellar travel, and also the annoying possibility that the human race already has the potential to self-destruction, developed rather shortly after the first radio emissions began.
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Message 237980 - Posted: 26 Jan 2006, 22:58:04 UTC

Yes, but when given an infinite amount of time before now, it's all moot. The equation works locally in time but the infinite amount of time allows aliens to already be populating other worlds with a distinct possiblity of already knowing that we are here or us being a result of their efforts. I guess that is the factor of "those who wish to communicate".

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Message 238233 - Posted: 27 Jan 2006, 14:26:11 UTC - in response to Message 237980.  

Yes, but when given an infinite amount of time before now, it's all moot. The equation works locally in time but the infinite amount of time allows aliens to already be populating other worlds with a distinct possiblity of already knowing that we are here or us being a result of their efforts. I guess that is the factor of "those who wish to communicate".

If the Universe has existed for an infinite length of time in a state similar to the present, then anything that could possibly happen already has happened. At some point, an intelligent race evolved from dryer lint has acheived interstellar travel. A version of the US and Soviet Union had their nuclear war and all of the nukes turned out to be duds. Somewhere, a scientist discovered the secret to universal happiness moments before his planet was engulfed in a solar flare. In some distant place and time there was a world in which machines enslaved the biological species and kept their minds active with a Matrix. And, most incredible of all, somewhere there is or was a world in which the things that Howard Dean says actually make sense.

I think that the Fermi Paradox is the biggest indictment against the Steady State Model. With an infinite amount of time to try, Nature must have spawned a species capable of colonizing the entire Universe.
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Message 238247 - Posted: 27 Jan 2006, 15:22:56 UTC - in response to Message 238233.  


I think that the Fermi Paradox is the biggest indictment against the Steady State Model. With an infinite amount of time to try, Nature must have spawned a species capable of colonizing the entire Universe.


But all observations that humans have made and based on our current knowledge, travel between galaxies would take a very very very long time. Warp technology for example is still currently fantasy which means we cannot assume that it's possible. This limitation to travel could severely limit the desire to go beyond ones galaxy which means that what ever lifeforms have done, there is a good chance that they stayed within their own galaxy. But a species capable of colonizing the entire Universe would be within the realm of conisderation but could the probabilities would still be quite low.

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Message 238252 - Posted: 27 Jan 2006, 15:33:10 UTC - in response to Message 238233.  
Last modified: 27 Jan 2006, 15:41:41 UTC

I think that the Fermi Paradox is the biggest indictment against the Steady State Model. With an infinite amount of time to try, Nature must have spawned a species capable of colonizing the entire Universe.


But as I see it, it is at this point that the Fermi paradox breaks down.

If we can conceive of one species (or collection of species) capable of colonizing the entire universe, then we can very easily conceive of more than one (an infinity in fact).

So what happens when these civilisations eventually meet up?

There could be infinitely long periods of peace and harmony interspersed with infinitely long periods of war and destruction, interspersed with infinitely long periods of decay and regeneration where there are only a few or no surviving species left.

Perhaps we are existing in one of these darker periods of time where the galactic civilisations destroyed themselves and everyone else billions of years ago leaving no surviving traces, and life is just starting up again from scratch.

If we can conceive of one civilisation obtaining ultimate power before anyone else, then we can also conceive of two or more civilisations achieving ultimate power at the same time before anyone else (in an infinite universe).

Of course at the end of the day, we don't know and we may never do so, but I'd love to find out.

If it ever happens in my lifetime that we find traces of the existence, past or present, of other forms of life or civilisations it won't bother me one bit if it turns out that we are way down in the pecking order of existence (so long as we're not turned into a batteries or pieces of steak, etc).


A nice little link: There Is No Fermi Paradox


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Sometimes I think we are alone in the universe, and sometimes I think we are not. In either case the idea is quite staggering.
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Message 238607 - Posted: 28 Jan 2006, 4:08:58 UTC - in response to Message 238233.  
Last modified: 28 Jan 2006, 4:11:18 UTC

If the Universe has existed for an infinite length of time in a state similar to the present, then anything that could possibly happen already has happened.


An interesting idea...

(1) Let A be the infinite set of all possible things that could happen in the universe, in infinite time.

(2) Let B be the set of things that have happened in the universe.

(3) Assume the universe is infinitly old.

Does (3) this imply that everything in A is in B? I don't think so, (3) doesn't even imply that B is infinite--for instance the same finite set of things could have happened in the universe over and over again, for infinite time. Thus the universe could be infintely old, and repetitive, and thus not everything that could happen has happened.

However

(4) Assume the universe does not repeat the same events.

1 through 4 now imply that both A and B are infinite. However, do they imply that everything in A is in B? Consider this analogy:

(a) Let A be the set of all numbers.
(b) Let B be the set of all integers.

Both A and B are infinite sets of numbers, yet B is a subset of A.

Similarly I think the universe, if infinitely old, could have assumed an infinite number of different states, but only a subset of possible states.



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Message 239031 - Posted: 28 Jan 2006, 23:18:50 UTC

this is of course completely disregarding that we have found the universe to be about 15billion years old
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Message 239034 - Posted: 28 Jan 2006, 23:27:58 UTC - in response to Message 239031.  

this is of course completely disregarding that we have found the universe to be about 15billion years old


This is completely disregarding that the "big bang" is ONLY a THEORY. It's been doctored so many times, it's sad. They use to think that universe was 4 billion years old until they realized that our sun was already 4.5 billion years old.

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Message 239122 - Posted: 29 Jan 2006, 3:38:59 UTC - in response to Message 238233.  
Last modified: 29 Jan 2006, 3:39:28 UTC

And, most incredible of all, somewhere there is or was a world in which the things that Howard Dean says actually make sense.


...then were going to go to Mars, then were going to go to Andramada, then on to Alpha Eta Pi, then were gonna take back the Black Hole!!!! WAHAHAAHHAHAHAHAH!
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Message 239198 - Posted: 29 Jan 2006, 6:36:41 UTC

I consider it possible that life may eventually self evolve into mechanized 'life'. What if the majority of life in the Universe has become machines? It won't be long before humanity will regard cyborgs as completely natural. Brain enhancement chips, brain replacement components, artificial mechanized limbs and organs hardwired into the neurologic structure, nanobots repairing tissues and maintaining the artificial components, etc.

Give it a million years .....?
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Message 239458 - Posted: 29 Jan 2006, 20:18:59 UTC - in response to Message 239198.  

I consider it possible that life may eventually self evolve into mechanized 'life'. What if the majority of life in the Universe has become machines? It won't be long before humanity will regard cyborgs as completely natural. Brain enhancement chips, brain replacement components, artificial mechanized limbs and organs hardwired into the neurologic structure, nanobots repairing tissues and maintaining the artificial components, etc.

Give it a million years .....?


can machines have life? sounds like battlestar galactica.
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Message 239475 - Posted: 29 Jan 2006, 20:36:05 UTC - in response to Message 239458.  

I consider it possible that life may eventually self evolve into mechanized 'life'. What if the majority of life in the Universe has become machines? It won't be long before humanity will regard cyborgs as completely natural. Brain enhancement chips, brain replacement components, artificial mechanized limbs and organs hardwired into the neurologic structure, nanobots repairing tissues and maintaining the artificial components, etc.

Give it a million years .....?


can machines have life? sounds like battlestar galactica.


No, silly. Those were just actors in costumes....

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Message 240867 - Posted: 2 Feb 2006, 3:55:50 UTC

At some point science will be able to duplicate the human brain in all aspects. How ever long that may take it will happen short of us annihilating ourselves.

So the question is, is that life?

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Message 240892 - Posted: 2 Feb 2006, 4:28:50 UTC - in response to Message 240867.  

At some point science will be able to duplicate the human brain in all aspects. How ever long that may take it will happen short of us annihilating ourselves.

So the question is, is that life?



Could be. If you figure that humans can now make single molecule transistors, making a brain is possible. We certainly fall short with understanding chemical memory storage and retrieval, though. What makes life? If something asks "why am I here?" without prompting, I would say that is is alive.

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Message 241522 - Posted: 3 Feb 2006, 15:52:14 UTC - in response to Message 238607.  

If the Universe has existed for an infinite length of time in a state similar to the present, then anything that could possibly happen already has happened.


An interesting idea...

(1) Let A be the infinite set of all possible things that could happen in the universe, in infinite time.

(2) Let B be the set of things that have happened in the universe.

(3) Assume the universe is infinitly old.

Does (3) this imply that everything in A is in B? I don't think so, (3) doesn't even imply that B is infinite--for instance the same finite set of things could have happened in the universe over and over again, for infinite time. Thus the universe could be infintely old, and repetitive, and thus not everything that could happen has happened.

I'm on a business trip with limited access to the web, so I'm sorry if there are long gaps between my posts.

The 'repeating' events could even be variations on a theme and still look infinite to someone inside the loop. Consider the surface of a sphere. To a bug crawling across that surface, it goes on forever. The bug might go around a little north of the equator one time, a little south another time, and eventually lose its bearings completely and end up on a circumpolar route. The bug is just going 'forward' forever as far as it is concerned.

If our intrepid bug has an infinite amount of time to crawl, it should cover every possible bit of the surface given enough time. There might be some inobvious quirk in its nervous system that leaves a certain patch of the sphere untouched, but for the moment lets assume its path is truly chaotic and would cover the whole thing.

Although our bug can travel for an infinite length of time in 'one direction' then it is a infinite surface. However, we know that a sphere has a finite surface area. All of the points that can be reached will be reached, but our bug might dream of points that don't fall on the sphere at all. Those are things that cannot happen, and they will not happen.

This is a way of saying that the Pulse and Superstring theories, which envision Universe after Universe repeating ad infinitum, do not necessarily mean that the exact same history repreats itself. Using the Pulse model as an example, the moments just before and just after the singularity might have This leads to a paradox... something should eventually come along powerful enough to prevent any challenge to its power... but given an infinite length of time, the Universe would throw a monkey wrench in it anyway. It's a version of "God can do anything. So can He make a rock so heavy that He cannot lift it?"

Going back to my bug-on-a-sphere for a moment, that inobvious nerve arrangement that makes the bug always miss a certain spot on the sphere would indicate potential history that never happens... going back to Pulse or Superstring theory, if physicists could figure out why it never happens, it could shed light on some of the most basic parameters of the Universe. It would interesting to nudge the system to go to that area and see what happens.
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Message 244735 - Posted: 8 Feb 2006, 20:58:33 UTC - in response to Message 237130.  

One of the difficulties for communicating with (supposed) extra-terrestrial civilizations is that.. the expected lifespan of an "intelligent" civilization may be only some decades or centuries under pessimistic assumptions. This is one of the most uncertain and limiting factors in the Drake equation. The situation would be quite different if the lifetime of intelligent beings would be much longer, say, some 10,000 or 100,000 years.


Indeed. So far we've been communicating with radio waves for about 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? And even if the human race survives another 100,000 years will we not soon, say in the next 100 to 500 years, resort to some more sophisticated encoding scheme for our communications making them undectable by an alien civilization running a seti program similar to our current one? I believe so. Thus I fear that when calculating the term fL (the fraction of the planet's life during which the communicating civilizations live/communicates) the most optimistic answer is about 1/20,000,000th (500 years). That makes the chances of success very, very, slim because our current SETI project only scans frequencies of radio and TV emissions sent by a Type 0 civilization and not more advanced Type 1, II, or III civilizations. Your thoughts?


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