The thing that jumps out at me the most about this discussion is the assumption that life and intelligence will evolve and develop on other planets at the same rate it did here.

There are SO many things that can happen to a planet! Someone mentioned the dinosaurs.... If they hadn't been wiped out, who knows what they might have become? We never would have existed and Earth could be covered with super-intelligent lizards that could quite possibly be the kind of civilization we're looking for. But they DID die, and so everything started over.

And then there's things like the Dark Ages. We went through an awful period of almost no scientific advancement. If that hadn't happened, we could be several hundred years ahead of where we are now.

Also, on the flip side, life could develop much more slowly somewhere else. Just last night I read an old short story called "Glacial", basically about glaciers that were developing intelligence. It was developing so slowly that it was all but unrecognizable in a human lifetime.


It just doesn't make any sense to me to use our development as a "rule" to gauge what might be out there. I realize we don't have anything to go on, but there are too many variables. I doubt there is any standard rate of progress or any such thing.


And Sparrow, about "what version of history is he reading".... Unfortunately, the stuff poured into the brains of American students. :/ Everything concerning Native Americans in those textbooks is horribly one-sided.

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Moonshadow, I think you're absolutely correct. There's no guarantee that what we recognize as intelligence will ever evolve on other earth-like worlds. Had the dinosaurs not been eliminated, a species like the 'raptors of Jurassic Park might have held the top slot in the food chain for millions of years, and done so without opposable thumbs or fire. Or perhaps their curiosity and will to power would have taken them to the stars long ago. We'll never know. If we can ever manage to find and survey a few other earth-like planets, I think we'll know a lot more about what courses biology can take elsewhere.

History: I think it still exists as a living social science, but not anywhere outside of academia, and certainly not in American public schools. In truth, it never existed there. My partner's son is in elementary school, in a school system that's considered quite good. He's learning more history from playing video games than he's learning in school. (He does have a fair grasp of WW II already!) I think our education system will forever be cursed by "political correctness," and history suffers more than most subjects under that yoke.

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"Good against remotes is one thing. Good against the living, that's something else." (Han Solo)

There are SO many things that can happen to a planet! Someone mentioned the dinosaurs.... If they hadn't been wiped out, who knows what they might have become? We never would have existed and Earth could be covered with super-intelligent lizards that could quite possibly be the kind of civilization we're looking for. But they DID die, and so everything started over.

It actually seems to me that if the dinosaurs had not been wiped out and never gone extinct, then there would be no intelligent life on this planet at the moment.

You have to remember, evolution towards intelligence is not a linear process; dinosaurs had small brains, specialization, strong bodies, etc. There was no need to be too intelligent.

Then again, like you say, who knows?

And then there's things like the Dark Ages. We went through an awful period of almost no scientific advancement. If that hadn't happened, we could be several hundred years ahead of where we are now.

True, but my own take is that it doesn't really matter in the bigger picture.
Several hundred years, several thousand years, even a hundred thousand years; they're *extremely* small scales of time in terms of our galaxy as a whole.

Also, on the flip side, life could develop much more slowly somewhere else. Just last night I read an old short story called "Glacial", basically about glaciers that were developing intelligence. It was developing so slowly that it was all but unrecognizable in a human lifetime.

The consensus among astrobiologists at the moment seems to be that microbial life is likely fairly common and likely dominates a planet either for billions of years or even forever. It's not certain that complex animal life is a forgone conclusion.

It just doesn't make any sense to me to use our development as a "rule" to gauge what might be out there.

Makes sense to astrobiologists and SETI scientists.

The reason it's probably a safe bet to get at least *some* basic guidance from Earth's natural history is that nothing generally unusual or unexpected occurred. Earth's natural history seems fairly "common" and mundane, barring some specific features that set our planet apart from others in the solar system (such as tectonics, a strong magnetic field, a large moon, etc).

If Earth is fairly "normal" in terms of similarly-sized terrestrial planets in the habitable zones of other sun-like stars, then some basic generalizations can probably be drawn; like the long-term dominance of microbes...


Of course, in a fundamental way, you're absolutely right. There are a lot of missing pieces in the puzzle, not the least of which is the fact that we don't even have another single example of any other planet with life....

The Cambrian explosion, which marks the rise of complex animals, is still mostly unexplained, though possibly connected to the end of the Snowball Earth period... Unique climatic changes may occur at varying times sooner or later than they did on Earth.

It's a safe bet that in a galaxy of possibly hundreds of billions of stars, there will likely be extreme variation if life is common; but drawing some fundamental assumptions from Earth's own history can be a helpful tool...

Ralpher wrote:

"As for the Amer-Indians, while there was some genocide and some cultural extinction, most integrated with the Europeans."

My friend, I don't know what version of history you're reading. I doubt there are any American Indians alive today who would agree, and I doubt any historians familiar with this issue would, either. Active and occasionally violent confrontation between individuals, tribal governments, and white culture and government continues to this day.

You can visit the Mission de San Jose in Fremont California. Also talk to many families across the US you will find most are of Indian decent. The whole history of Indian and the Spanish Crown and the US is not fully told. History books today only show one side, and only cover a very small portion of the Indian tribes. There were thousands of tribes across the US.

In my family alone there is Cheyenne and Ohlone blood. I bet you have some too. So the Indians "alive today" are not only the ones on the reservations but in the populous at large. Which just about includes almost all Americans. So if you just talk to the ones in the reservations (none in California) then you are only getting half of the story. The other half is buried.

Also most of the bloody wars occurred on the planes, not on the East or West coasts.

Anyway my point was that there are two options for when a more advanced species meets a lesser advanced species not just one. There's a bloody way and a peaceful way. Though both are not without great struggle.

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You're absolutely right, and indeed, astrobiologists are fairly confident that the majority of stars are *not* capable of producing life or even a civilization.

If that's the case, then the odds are continually reduced that a civilization is close to ours in age since the total number of possible civilizations is reduced.

Thanks, I was suspecting as much.

Well, right, but we don't know that every star system produces a civilization or life. Our Sun is alone, but most star systems are binary. That could be a criteria for life. So I did not refer to stars but civilizations. To equate stars with civilization might be generally acceptable, but in the long run it might prove to be inaccurate.

Not sure I follow your logic here...

If we don't use the age of a star as an indication of how long life has evolved on any given planet (and therefore, we don't extrapolate the time it took intelligence to evolve on Earth), then aren't you saying it's even *LESS* likely for a civilization to be within even a few millennia of ours??

No, not at all. I'm just trying to suggest that Star formation is more indirect than direct to life. So just because the stars are there doesn't automatically mean that life will form. That between a star formation and its system containing life there are many processes that must take place.

This is apart from timing of the birth of two or more civilizations.

For example Earth. (Sorry its the only example I got). Earth has several factors that favor life. Distance from the Sun for optimum temperature, formation of a nitrogen and oxygen atmosphere and gravity to provide air pressure, a large moon, lots of water, gas giant planets diverting comets and asteroids from it...etc. All of these processes work together to keep the 'spark of life' flourish on Earth.

If we assume that a civilization can arise at any point in time during the lifespan of a star, then you're actually making the odds even worse that a civilization is close to ours in age; you're increasing the the range of possible ages on scales of billions of years.

That the opposite of what I'm saying. I'm bringing the macro down towards the micro. That is looking at the premise of Star formation equals life formation a little closer. So any increment in time wouldn't be so large.

Depends on the scope you looking at. If your scope is in centuries then your probably right, but if its in millenia then you might find that civilizations occur like most social economic entities. That is along a bell curve, hence statistics.

Not sure I understand what you mean here.

Just evaluating with basic statistical principles. The principal that most population issues follow a bell curve. In this case that civilizations most probably pop up closer together in time than not.

BTW, I'm no "absolutist"... I'm just describing the rationale behind current radio SETI projects like SETI@Home and the work of the SETI Institute.

Don't take it personally, its a basic human tendency to give up on an idea and respond with an absolute statement that no one can respond to. I think the challenge in these discussions is to keep the discussion going.

They're all based on the fundamental assumption that a transmitting civilization will be much older than ours; on scales of millions of years. Even if there were other civilizations in the galaxy that *are* close to us in age, SETI does not expect or have practical means to detect them; SETI is only listening for older civilizations. If there are no other civilizations in the galaxy significantly older than we are, then SETI is doomed to fail.

That's the fundamental basis of SETI.

Since we're all here crunching for SETI@Home, I'd think we all hope that basis is accurate. ;P

Well I do it because they might be right. I also do it because they might be wrong. In any case they are trying, and that's more than anyone else is doing.

To me the success of SETI is not necessarily if they find an advance civ or if they don't. That's because either way we are exploring and we will learn from it.

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And then there's things like the Dark Ages. We went through an awful period of almost no scientific advancement. If that hadn't happened, we could be several hundred years ahead of where we are now.

I would like to chime in. The Dark Ages were terrible, but it led up to the reformation which led up to the enlightenment period. These created a culture of writers and record keepers that gave us history and technology to begin with. Everything before that had to be uncovered and rediscovered.

If you look at ancient China, we think of an advance society relative to Europe. But actually ever time an emperor died, documents and technology were lost by burning. And China had to start all over anew.

So its not that no one knew how to make steam engines or use hydrolics in ancient times (not to mention batteries and electricity), its just the sharing of information was not there. Until the enlightenment.

If people were only willing to share from generation to generation then we'd be far more advanced than today.

That's why the loss of the library of Alexandria was a such a terrible loss.

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You're right, we are latecomers to the galaxy (since the Sun is relatively young and our civilization is only thousands of years old), the "new kids on the block"... ;)

If there are no other civilizations and we're really the first, then we are left with an incredible riddle; why didn't any civilizations ever arise before us? If this really is the case, then intelligent life must be a breathtaking fluke, a freak occurrence which only happens once in billions of years among billions of stars in a single galaxy.

I have a possible answer. That the seed of life is just taking root at the time of life on Earth started. Maybe the galaxy needs to be a particular age before life can sprout. Before stars like our Sun can form (by size, planets, and being single). What if were at the beginning of the bell curve of life sprouting? Millions of civilizations could be on there way of evolving.

At the same token we could be at the end as well. Millions of civilizations could have come and gone and are no more and we are the last in the galaxy. Ok that was a scary thought.

But I think that is what SETI is geared for best. That we're among the last of life in the Milky Way.

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Ralpher wrote:

"At the same token we could be at the end as well. Millions of civilizations could have come and gone and are no more and we are the last in the galaxy. Ok that was a scary thought."

Yes, but I'll offer a scarier or sadder one--the possibility that the Olduvai theorists are right, and the life expectancy of any industrial civilization is only a century or two, until available natural resources are used up. (See http://en.wikipedia.org/wiki/Olduvai_theory) Certainly the length of this "resource window" could vary wildly. But the notion that many/most/all rising civilizations might not be able to solve the porblem of outrunning resources is sobering.

"Also talk to many families across the US you will find most are of Indian decent."

I don't want to hijack this thread, so I'll just urge you to reconsider your thoughts about this. I think "most" would be incorrect. Vast numbers of immigrants arrived here during the late 1800's, on the East Coast. The "Indian question" was all but settled almost everywhere in the country by then. You might also check out the Pequot War of 1637 and the Indian Removal Act of 1830.

And Happy 4th!

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"Good against remotes is one thing. Good against the living, that's something else." (Han Solo)

No, not at all. I'm just trying to suggest that Star formation is more indirect than direct to life. So just because the stars are there doesn't automatically mean that life will form. That between a star formation and its system containing life there are many processes that must take place.

This is apart from timing of the birth of two or more civilizations.

For example Earth. (Sorry its the only example I got). Earth has several factors that favor life. Distance from the Sun for optimum temperature, formation of a nitrogen and oxygen atmosphere and gravity to provide air pressure, a large moon, lots of water, gas giant planets diverting comets and asteroids from it...etc. All of these processes work together to keep the 'spark of life' flourish on Earth.

Yes, that's all a given.
The odds for any given set of circumstances to occur that may or may not be relevant to the chances of the rise of a civilization would go up or down depending on how many specific circumstances need to be in place.

The more processes that need to work together in any one planet for a civilization to arise, the less likely it is that that civilization's age will overlap ours within a short time frame. Also, the greater the variety of possible circumstances in which any given civilization can arise, the less likely it is that a civilization's age will overlap ours within a short time frame as well.....

That the opposite of what I'm saying. I'm bringing the macro down towards the micro. That is looking at the premise of Star formation equals life formation a little closer. So any increment in time wouldn't be so large.

I'm genuinely not seeing the connection here.
How does what you're saying about the various circumstances which can lead to the rise of a civilization lead you to assume that the "increment in time wouldn't be so large"? I'm really struggling to see how you're drawing that conclusion.

Just evaluating with basic statistical principles. The principal that most population issues follow a bell curve. In this case that civilizations most probably pop up closer together in time than not.

What is the basis for your conclusion? I'm not certain I understand...

Are you saying that since there is a statistical phenomenon known as a bell curve, that civilizations probably pop up close together in time?
I think that's a vast misunderstanding of statistics and exactly what a bell curve is. A bell curve cannot be arbitrarily applied to any given phenomenon or twisted to fit an arbitrary set of data....particularly when the fundamental data set for which you're making assumptions is unknown (the total number and ages of the civilizations in the Milky Way galaxy), and you're arbitrarily disregarding another data set which *IS* known (the average ages of terrestrial planets in the Milky Way Galaxy) because you assume it's not germane.

Since geologists, biologists, anthropologists, and astrobiologists agree that the Earth's age *IS* relevant to the history of life and the age of the civilization on this planet, it seems extremely likely the ages of terrestrial planets on which other civilizations exist would also be relevant and statistically connected in a quantifiable way to the ages of those civilizations.

Even if a bell curve *could* be applied to the ages of civilizations in any given galaxy, you seem to be vastly underestimating the time scales in the universe: hundreds of millions of years would constitute "closer together in time". When scientists see two stars being born in the same stellar nursery and conclude that they are a few million years apart in age, they conclude that they are nearly twins, "born at practically the same time". If a bell curve could be applied to all civilizations in our galaxy, wouldn't they be "close together in time" in scales of millions of years or more?

In a hypothetical future in which we had the ability to conduct a complete and thorough survey of every civilization in the entire galaxy and found that their ages could be plotted reliably on a bell curve, what is the basis for your assumption that the bell curve would only cover a scale of thousands or tens of thousands of years?

As far as the possibility of a bell curve even being applicable to the ages of civilizations, it seems to me that the circumstances responsible for such a statistical reality would be extremely difficult to even guess at considering that, as I've said, there is nothing particularly special about this point in time in the age of the galaxy or the universe or the average ages of stars or planets.

I'm not sure you're taking into account the fact that the course of natural history on any planet around any star in the galaxy unfolds *absolutely 100% SEPARTELY and in isolation from any other planets around any other stars in the galaxy* in terms of all known natural phenomenon that we can account for. Every star system is truly an island utterly unto itself.

Barring local events such as supernovae or gamma ray bursts, the natural histories (geological or biological) of planets in any star system would unfold completely 100% independently of star systems anywhere else in the galaxy or universe.

What exactly makes you think that the natural history of a world 100,000 light years away at the other end of the galaxy would be closely influenced by the natural history of Earth such that events on both worlds would be timed to coincide within a few thousand years or less??.....especially since that world on the other end of the galaxy could be anywhere from a 10 billion years older than Earth to 4 billion years younger than Earth??....

Unless there is some synchronous galaxy-wide event that takes place across 100,000 light years that equally influences all planets with life on them, there is no known natural mechanism to synchronize the natural histories of worlds orbiting stars that are light years apart from each other: To account for proposed synchronicity in the ages of civilizations, you'd have to invent a mechanism that is not known to exist.

As of right now, there's no data set that suggests that a bell curve can be applied to the ages of the galaxy's civilizations; there's no reason, no known information, no set of circumstances that can be extrapolated to support such a conclusion at this time. You're free to believe that it ultimately may be the case, but at this point, you're introducing an unnecessary variable which is not supported by any known data. It's a violation of Occam's Razor and the Mediocrity Principle. You might as well assume that most civilizations like the color purple. That ultimately may be the case, but there's no data from which we can extrapolate to support such an assumption even on a hypothetical basis.



You say you're using "basic statistical principles", but you aren't. That in itself doesn't make what you're saying "wrong". I tend to think that statistical analysis based on known data sets is a helpful tool, just as SETI scientists do, and can aid in our assessments of possibilities concerning ET. Since the ultimate data set we're making conclusions about is unknown (extraterrestrial civilizations), I suppose it's fair to assume that's anything's possible.

However, statistics dictates that some possibilities are more likely than others, even though we ultimately don't know for sure.

Don't take it personally, its a basic human tendency to give up on an idea and respond with an absolute statement that no one can respond to. I think the challenge in these discussions is to keep the discussion going.

The challenge for me is to understand how you're drawing your conclusions, otherwise I can't really respond to them, and instead end up repeating myself.


EDIT:

Here's an article by the SETI Institute's Seth Shostak that's relevant to the topic-
http://www.seti.org/news/features/are-we-the-galaxys-youngest.php


BTW:
Do you also assume that the forming of North America's Great Lakes or the Himalayas or the extinction of the Neanderthals are also correlated along a bell curve with other planets orbiting other stars across the 100,000 light years of interstellar space that makes up our galaxy? If not, then what makes you assume it would be true of civilizations?

You're essentially saying that the rise of agriculture and the founding of the first cities in Mesopotamia can be correlated along a bell curve with other planets orbiting the 200-400 billion stars from here to the other end of the galaxy, right?.... You believe that this event was essentially happening at nearly the exact same time throughout the entire galaxy? Do you really believe that's likely? If so, then what do you propose is responsible for that synchronicity?

Ralpher wrote:

"At the same token we could be at the end as well. Millions of civilizations could have come and gone and are no more and we are the last in the galaxy. Ok that was a scary thought."

Yes, but I'll offer a scarier or sadder one--the possibility that the Olduvai theorists are right, and the life expectancy of any industrial civilization is only a century or two, until available natural resources are used up. (See http://en.wikipedia.org/wiki/Olduvai_theory) Certainly the length of this "resource window" could vary wildly. But the notion that many/most/all rising civilizations might not be able to solve the porblem of outrunning resources is sobering.

Yes, that is scary.

"Also talk to many families across the US you will find most are of Indian decent."

I don't want to hijack this thread, so I'll just urge you to reconsider your thoughts about this. I think "most" would be incorrect. Vast numbers of immigrants arrived here during the late 1800's, on the East Coast. The "Indian question" was all but settled almost everywhere in the country by then. You might also check out the Pequot War of 1637 and the Indian Removal Act of 1830.

And Happy 4th!

We can agree to disagree, but I'll say my position is based on talking to many US Citizens across the US.

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That the opposite of what I'm saying. I'm bringing the macro down towards the micro. That is looking at the premise of Star formation equals life formation a little closer. So any increment in time wouldn't be so large.

I'm genuinely not seeing the connection here.
How does what you're saying about the various circumstances which can lead to the rise of a civilization lead you to assume that the "increment in time wouldn't be so large"? I'm really struggling to see how you're drawing that conclusion.

Because its a subset of smaller events and it has to fit within the larger events.

[/quote]

Just evaluating with basic statistical principles. The principal that most population issues follow a bell curve. In this case that civilizations most probably pop up closer together in time than not.

What is the basis for your conclusion? I'm not certain I understand...[/quote]

Please, don't mistake this experiment in logical thought for a conclusion.

Are you saying that since there is a statistical phenomenon known as a bell curve, that civilizations probably pop up close together in time?
I think that's a vast misunderstanding of statistics and exactly what a bell curve is. A bell curve cannot be arbitrarily applied to any given phenomenon or twisted to fit an arbitrary set of data....particularly when the fundamental data set for which you're making assumptions is unknown (the total number and ages of the civilizations in the Milky Way galaxy), and you're arbitrarily disregarding another data set which *IS* known (the average ages of terrestrial planets in the Milky Way Galaxy) because you assume it's not germane.

Is there any other statistical model available? When were talking about civilizations we are talking biology. Don't clusters of life spawn following a bell curve?

Since geologists, biologists, anthropologists, and astrobiologists agree that the Earth's age *IS* relevant to the history of life and the age of the civilization on this planet, it seems extremely likely the ages of terrestrial planets on which other civilizations exist would also be relevant and statistically connected in a quantifiable way to the ages of those civilizations.

Unfortunatley they don't agree on timing.

Even if a bell curve *could* be applied to the ages of civilizations in any given galaxy, you seem to be vastly underestimating the time scales in the universe: hundreds of millions of years would constitute "closer together in time". When scientists see two stars being born in the same stellar nursery and conclude that they are a few million years apart in age, they conclude that they are nearly twins, "born at practically the same time". If a bell curve could be applied to all civilizations in our galaxy, wouldn't they be "close together in time" in scales of millions of years or more?

I never stated any specific timescales. I'm not underestimating. In this discussion time has to be treated relatively.
[/quote]

In a hypothetical future in which we had the ability to conduct a complete and thorough survey of every civilization in the entire galaxy and found that their ages could be plotted reliably on a bell curve, what is the basis for your assumption that the bell curve would only cover a scale of thousands or tens of thousands of years?
[/quote]
Or billions, or tillions, or quadrillions....etc...etc...etc...
There is no 'only'. Infinity is the limit.

As far as the possibility of a bell curve even being applicable to the ages of civilizations, it seems to me that the circumstances responsible for such a statistical reality would be extremely difficult to even guess at considering that, as I've said, there is nothing particularly special about this point in time in the age of the galaxy or the universe or the average ages of stars or planets.

If it doesn't follow a bell curve what curve do you suggest it follows? A square curve? 'J' curve, 'S' curve? If J or S then you assume the number of civilisations in a galaxy never decreases.

I'm not sure you're taking into account the fact that the course of natural history on any planet around any star in the galaxy unfolds *absolutely 100% SEPARTELY and in isolation from any other planets around any other stars in the galaxy* in terms of all known natural phenomenon that we can account for. Every star system is truly an island utterly unto itself.

Earth and life on Earth is affected by Jupiter and the moon. No planet is an island.

Barring local events such as supernovae or gamma ray bursts, the natural histories (geological or biological) of planets in any star system would unfold completely 100% independently of star systems anywhere else in the galaxy or universe.

I guess you don't believe in cosmic radiation then.

What exactly makes you think that the natural history of a world 100,000 light years away at the other end of the galaxy would be closely influenced by the natural history of Earth such that events on both worlds would be timed to coincide within a few thousand years or less??.....especially since that world on the other end of the galaxy could be anywhere from a 10 billion years older than Earth to 4 billion years younger than Earth??....

Don't think I'm saying that.

Unless there is some synchronous galaxy-wide event that takes place across 100,000 light years that equally influences all planets with life on them, there is no known natural mechanism to synchronize the natural histories of worlds orbiting stars that are light years apart from each other: To account for proposed synchronicity in the ages of civilizations, you'd have to invent a mechanism that is not known to exist.

Its not that one affect another, its that the Galaxy operates as one entity. And therefore timing of different planets and but they follow a similar path of existence.

As of right now, there's no data set that suggests that a bell curve can be applied to the ages of the galaxy's civilizations; there's no reason, no known information, no set of circumstances that can be extrapolated to support such a conclusion at this time. You're free to believe that it ultimately may be the case, but at this point, you're introducing an unnecessary variable which is not supported by any known data. It's a violation of Occam's Razor and the Mediocrity Principle. You might as well assume that most civilizations like the color purple. That ultimately may be the case, but there's no data from which we can extrapolate to support such an assumption even on a hypothetical basis.

There is no data of any group of galactic civilization! So were left with hypothesizing.

You say you're using "basic statistical principles", but you aren't.

Why the hostility? This is uncalled for. If you disagree say so. But to say the bell curve is not part of basics statistical principles is silly.

That in itself doesn't make what you're saying "wrong". I tend to think that statistical analysis based on known data sets is a helpful tool, just as SETI scientists do, and can aid in our assessments of possibilities concerning ET. Since the ultimate data set we're making conclusions about is unknown (extraterrestrial civilizations), I suppose it's fair to assume that's anything's possible.

However, statistics dictates that some possibilities are more likely than others, even though we ultimately don't know for sure.

Don't take it personally, its a basic human tendency to give up on an idea and respond with an absolute statement that no one can respond to. I think the challenge in these discussions is to keep the discussion going.

The challenge for me is to understand how you're drawing your conclusions, otherwise I can't really respond to them, and instead end up repeating myself.


EDIT:

Here's an article by the SETI Institute's Seth Shostak that's relevant to the topic-
http://www.seti.org/news/features/are-we-the-galaxys-youngest.php


BTW:
Do you also assume that the forming of North America's Great Lakes or the Himalayas or the extinction of the Neanderthals are also correlated along a bell curve with other planets orbiting other stars across the 100,000 light years of interstellar space that makes up our galaxy? If not, then what makes you assume it would be true of civilizations?

Not biological entities.

You're essentially saying that the rise of agriculture and the founding of the first cities in Mesopotamia can be correlated along a bell curve with other planets orbiting the 200-400 billion stars from here to the other end of the galaxy, right?.... You believe that this event was essentially happening at nearly the exact same time throughout the entire galaxy? Do you really believe that's likely? If so, then what do you propose is responsible for that synchronicity?

The galaxy has a beginning and an end.

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You're essentially saying that the rise of agriculture and the founding of the first cities in Mesopotamia can be correlated along a bell curve with other planets orbiting the 200-400 billion stars from here to the other end of the galaxy, right?.... You believe that this event was essentially happening at nearly the exact same time throughout the entire galaxy? Do you really believe that's likely? If so, then what do you propose is responsible for that synchronicity?

EXACT??? No. Relative timing not exact. But relative synchronicity is due to the fact that the galaxy has a beginning and an end.

And relative can be billions of years off.

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We can agree to disagree, but I'll say my position is based on talking to many US Citizens across the US.

Off-topic here but....
Surely you realize that's not a very scientific methodology you're using to come to that conclusion??

Is there any other statistical model available?

Of course there is; The models which SETI scientists and astrobiologists use. ;)

Don't clusters of life spawn following a bell curve?

That question doesn't have any real meaning unless it's asked in a very specific and relevant context.
You're using general terms in an arbitrary way too.
What do you mean by "clusters"?
What do you mean by "spawn"?
Where are you referring to? Locally here on Earth?

The linear growth in the complexity of biological life on Earth over the time scale of its existence on Earth (the last 3.8 billion years) cannot be fit to a bell curve, no.

Unfortunatley they don't agree on timing.

Could you explain?

Or billions, or tillions, or quadrillions....etc...etc...etc...
There is no 'only'. Infinity is the limit.

If you don't actually think that it's likely that most civilizations in the galaxy would differ in age with ours within thousands of years, then it seems I've been arguing against a point that doesn't exist.

As far as "trillions, quadrillions, infinity"; the universe is estimated to be approximately ~13 billion years old, and our Milky Way Galaxy nearly the same age, so there is an upper limit as far as how old a civilization in our universe can be right now.

Even if the estimates are *vastly* wrong, "infinity" is in fact not a potential limit, since the question of the nature of the universe and whether it had a beginning were solved more than half a century ago when the Big Bang theory was being developed and refined.

If it doesn't follow a bell curve what curve do you suggest it follows? A square curve? 'J' curve, 'S' curve? If J or S then you assume the number of civilisations in a galaxy never decreases.

Your premise is false since I never suggested that the relative ages of all civilizations in our galaxy do not fit a bell curve. There is no reason to arbitrarily apply a bell curve since such a phenomenon would have no basis or root in our currently known data set from which practical guesses can be drawn. Indeed, the ages of civilizations in our galaxy may in fact fit a bell curve; though the curve would likely be on a scale of billions of years.

My own personal guess:
Since the latest research suggests that the levels of metalicity required to form terrestrial planets like Earth did not exist in abundant enough quantities outside the core of our galaxy until ~7-8 billion years ago.
This same research has concluded that average age of all metal-rich, terrestrial Earth-like planets in the galaxy is approximately ~1.8 billion years older than our Earth.

Since I personally believe that once an intelligent civilization arises, it's probably very unlikely it will ever go extinct, and I also believe that the general time scale at which complex life arose on Earth is likely the norm, it would stand to reason that the average civilization in our galaxy is roughly ~1.8 billion years older than ours.

Earth and life on Earth is affected by Jupiter and the moon. No planet is an island.

I said "every star system is an island". The statement is clear right there in the quote you posted. I said the course of life on any planets "in any one star system" would unfold completely separately and independently from the local events on a planet orbiting a star 100,000 light years away.

If Carbon-based biology and intelligent civilization are universal phenomena, then perhaps similar rates of evolving biological complexity and/or technological progress can be assumed; just similar growth rates can be assumed for particular stars, no matter where they are.

...But for the advent of civilizations in other star systems to synchronize so utterly closely with ours as to be within a few thousand years of age, some simultaneous Galaxy-wide event would be required to cause such synchronicity; as of now, we know of no such synchronizing phenomenon in this galaxy.

I guess you don't believe in cosmic radiation then.

Ummm....OK....now you're just blatantly ignoring the parts of my post you're quoting. In the quote directly above your comment, I said this:
"Barring local events such as supernovae or gamma ray bursts..."

Uh...you realize that those events *cause* interstellar cosmic radiation, right?? I said "barring local events"...how could I be more clear more than that?

Don't think I'm saying that.

If you're not saying that, then I've misunderstood you.

Its not that one affect another, its that the Galaxy operates as one entity. And therefore timing of different planets and but they follow a similar path of existence.

I mean no disrespect here, sincerely, but that sentence by itself doesn't mean anything.

If you're suggesting that classes of objects in our galaxy follow similar paths of existence, such as stars of the same type, then yes, of course you're absolutely right! Indeed, we agree, I just said this above!

We can extrapolate observations of our sun to determine the pasts and futures of other Sun-like stars that we observe hundreds of light years away.

"Following a similar path of existence" is not the same thing as "synchronizing specific events in the course of their independent natural histories such that they occur at nearly the EXACT same time simultaneously throughout the entire galaxy, regardless of the relative ages of those stars."

Here's a simple example:
Tau Ceti is a Sun-like star some light years away from us. Like the Sun, it is a G-Dwarf.
However, unlike our Sun, Tau Ceti has a stable and "dull" surface, with very little magnetic activity. In comparison, our Sun is "hotter" than Tau Ceti and has a significantly more active surface.

Some scientists believe that we are currently observing Tau Ceti as it is going through a period of extremely low surface activity known as a Maunder Minimum, which is believed to happen to Sun-like stars as often as once every several hundred years.

Even with such common frequency, if every single Sun-like star was known to be going through a Maunder Minimum right now at this very moment, it would strike our scientists as incredibly odd and vastly unlikely. It would be so unlikely, that some Galaxy-wide event or effect would be necessary to explain the synchronicity which should be happening independently to every star at different times.

It would be as though you woke up one day and saw that every single person in your city was wearing blue today. It's so unlikely, that chance alone couldn't be responsible, and it would be more likely that some city-wide event could explain the phenomenon.

There is no data of any group of galactic civilization! So were left with hypothesizing.

There is ample data regarding biological evolution and the course of natural history of one planet, its civilization, and the star it orbits. There is also ample data regarding other similar stars throughout the galaxy. So far it's the only data from which can reasonably extrapolate.

The galaxy has a beginning and an end.

What exactly do you mean and in what way are you assuming it is relevant to the topic?

Yes, the galaxy did have a historical beginning in time.
The oldest stars in our galaxy are believed to be nearly as old as the universe itself, perhaps as much as ~13 billion years old. The galaxy's disk in which our solar system resides is currently believed to be as much as ~10 billion years old.

It is currently believed that our galaxy will collide with the Andromeda galaxy in ~3 billion years, eventually forming a new galaxy as both cores merge and all stellar material settles to orbit a new supermassive black hole.

EXACT??? No. Relative timing not exact. But relative synchronicity is due to the fact that the galaxy has a beginning and an end.

Well, if there are civilizations within our galaxy with ages that are synchronous to our own within a few thousand years, then that would be pretty "exact" considering the infinitesimal fraction of time our civilization has existed on the backdrop of the total time life and our planet have existed.

I'm not sure how you're relating "the galaxy has a beginning and an end" to this...

And relative can be billions of years off.

Certainly, I agree.

Since more words have been typed about this than probably need to be, here's a decent image that underlines the point fairly well. After all, an image is worth a thousand words.

http://upload.wikimedia.org/wikipedia/commons/f/fe/Geologic_clock.jpg

The image depicts a timeline of the natural history of our planet, including the evolution of life and the rise of humanity.

The history of human civilization over the course of the last ten thousand years is so tiny a fraction of this timescale that it cannot even be visually represented in the image!!

Now, consider that other Earth-like planets throughout our galaxy range anywhere from billions of years older than Earth to billions of years younger than Earth. The chance that a civilization on one of those planets intersects our civilization in age by a mere few thousand years is essentially zero!

As you can see plainly how overwhelmingly small a fraction of our planet's existence our civilization has been here, there would *have* be some kind of galaxy-wide event, some kind of phenomena as of yet unknown, to synchronize civilizations on other planets of varying ages so that the ages of their civilizations coincide with ours within that incredibly tiny fraction, so small that it's invisible on the scale!

As SETI scientists have said, the only way SETI can succeed is if the other civilizations in our galaxy occupy a MUCH larger chunk of that timescale than ours does...

Since more words have been typed about this than probably need to be, here's a decent image that underlines the point fairly well. After all, an image is worth a thousand words.

http://upload.wikimedia.org/wikipedia/commons/f/fe/Geologic_clock.jpg

The image depicts a timeline of the natural history of our planet, including the evolution of life and the rise of humanity.

The history of human civilization over the course of the last ten thousand years is so tiny a fraction of this timescale that it cannot even be visually represented in the image!!

Now, consider that other Earth-like planets throughout our galaxy range anywhere from billions of years older than Earth to billions of years younger than Earth. The chance that a civilization on one of those planets intersects our civilization in age by a mere few thousand years is essentially zero!

As you can see plainly how overwhelmingly small a fraction of our planet's existence our civilization has been here, there would *have* be some kind of galaxy-wide event, some kind of phenomena as of yet unknown, to synchronize civilizations on other planets of varying ages so that the ages of their civilizations coincide with ours within that incredibly tiny fraction, so small that it's invisible on the scale!

As SETI scientists have said, the only way SETI can succeed is if the other civilizations in our galaxy occupy a MUCH larger chunk of that timescale than ours does...

OMG its half of a bell curve. LOL! :)

Finally something positive input. Like the graph. I agree with you about the timescale. We as a planet 'have only just begun to live' (Carpenters, 1970). Therefore I think SETI should go on indefinitely.

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IN CONCLUSION (on my corn field analogy and following a bell curve [standard deviation] to imagine civilisations across the Galaxy), after deviating,

The more SETI delays in finding advanced ET, the more probability that our existence among the civilizations in the Galaxy lies further away from the tail end of the bell curve and more towards + 1 Standard Deviation.

So as SETI tarries more and more our position could lie next to the mean of the curve and then to the -1 Standard Deviation position and then to the beginning.

Thus coming to the conclusion that is suggested by the title of this thread.

To answer it, What if we are the first? Then SETI won't find advance civilizations.

This is my only conclusion!

The analogy was a thought experiment using some logic and some Standard Deviation (bell curve) principles. If your worried whether it applies or not I suggest you hide and watch. Its really not worth your effort to discredit it. Why not come up with a thought experiment yourself and see if you come to the same conclusion as I did.

P.S. To Taurus's credit he tried hard to understand my line of thinking. But my thinking is so obtuse that not many can follow.

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There is ample data regarding biological evolution and the course of natural history of one planet, its civilization, and the star it orbits. There is also ample data regarding other similar stars throughout the galaxy. So far it's the only data from which can reasonably extrapolate.

Taurus one point. Data on biological evolution and data on star formation may not correlate.

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If an advanced civilisation existed out-there, why do we assume that they would actually want to talk to us.

Trying to keep an open mind on the subject, we think in humans forms and assume human patterns to social interactions and communication. if an alien species were out-there now then they would by nature be alien, they may have no concept of what we call society, perhaps they have a "hive mind" or perhaps they are extreme loners to the point of being what we would term extreme hermits.

What if they are happier just keeping an eye on us until we get advanced enough to go into deep space... and pose some sort of potential threat to them... then they communicate. Until then its "all quiet on the front" after all the saying "lose lips sink ships" applies to home planets...

We may yet find the galaxy to be teeming with life, they just dont want any more communication or competition than necessary. perhaps mans dream of spreading to new planets is just that... a dream... as they are already taken, or being taken now by the other species..?

who knows??? not me.

personally I think "something" is happening... just what is another matter.


something

personally I think "something" is happening... just what is another matter.


something

personally I think "something" is happening... just what is another matter.
Well at least you are all thinking and you all may be correct . How about this idea? Those alliens that everyone is looking for havent left this planet yet. Ponder that one.

something

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