# Where is Everybody? Fifty solutions to the Fermi Paradox, by Stephen Webb



## Anthony G Williams (May 9, 2009)

The Fermi paradox is named after the mid-twentieth century physicist who posed a simple question: calculations based on reasonable estimates indicate that this galaxy should host a large number of extraterrestrial civilisations capable of interstellar communication or travel (which Webb shortens to ETCs), yet we have so far been unable to find any evidence for the existence of even one such civilisation. So where are they all? 

The astronomer Drake later quantified the calculation like this: the number of ETCs in the galaxy (N) is determined by the rate at which stars form (R), the fraction of stars with planets (fp), the number of those planets with an environment suitable for life (ne), the fraction of those planets on which life actually develops (f1), the fraction of those which produce intelligent life (fi), the fraction of those which develop a civilisation capable of interstellar communications (fc), and finally the number of years that such a culture will devote to communication (L). The "Drake equation" therefore reads N=(R)x(fp)x(ne)x(f1)x(fi)x(fc)x(L). This looks impressively authoritative, but a moment's thought reveals that we have no means of knowing most of the factors, so figures which we enter for them are little better than guesswork. And the calculated number of ETCs will vary greatly depending on the particular guesses we make. Another point is that should any of the factors be zero, then the outcome will also be zero. Despite this, calculations of star formation rates for this galaxy result in N being a very large number even with pessimistic assumptions being made about the other factors. In other words, this galaxy should have been swarming with ETCs for millions of years, which we could hardly have failed to notice.

Having discussed this paradox, the author then briefly describes and evaluates a select fifty (there have been many more) explanations put forward to account for this interstellar silence, before revealing his own solution. As the reviewer, I will of course conclude by proposing a slightly different answer! Webb divides up the explanations into three broad categories: "They are here"; "They exist but have not yet communicated"; and "They do not exist". I'll take each of these in turn; I obviously can't do justice to a book full of ideas in a blog, so I'll just pick a few examples.

*They Are Here*

This group contains only eight explanations, ranging from the amusing (they exist and are meddling in human affairs), through the paranoid (we have been isolated by the galactic civilisation, or we live in a simulation), to the more serious (panspermia: we are all aliens, because life was kicked off by being seeded from outer space) and finally the religious (God created this universe only for us; any other ETCs have their own universes created for them).

Webb clearly doesn't rate any of these very highly. The most feasible, panspermia, doesn't actually solve the problem, since if our planet was seeded so presumably was every other suitable one – so where are they all?

*They Exist But Have Not Yet Communicated*

More than twenty explanations here, some of which argue that ETCs may for various reasons not be interested in travelling to, or even communicating with, other civilisations. Just because we are explorers doesn't mean that everyone else has to be. However, Webb points out that it only takes one with the same urges as we have to reach out to other worlds, and potentially spread throughout the galaxy. 

Other explanations are therefore more practical, focusing on the difficulty of interstellar communication – let alone interstellar travel. The popular belief that ETCs in our neighbourhood would have detected us now via our routine radio and TV broadcasts is shot down; it appears that these would fade out before they could reach even the nearest star. Even a focused radio beam aimed at another star would be hard to detect; lasers are more promising, but a nearby ETC would have to exist now, and be beaming a signal directly at us, and we would have to be looking in the right place at the right time to notice it. Another idea is that they are signalling but we're not picking it up, for various reasons; or we have picked it up, but haven't properly analysed the data. Or possibly ETCs don't spend long in an active signalling phase before they upload themselves into computers or some higher non-material plane to enjoy the unlimited pleasures of virtual reality.

The difficulties of interstellar travel are well rehearsed, since there are no indications that Faster-Than-Light (FTL) spaceships will ever be possible and frozen sleep or generation ships have their own major problems. Bracewell-Von Neumann probes (which are sent to other star systems to mine their resources and then replicate themselves to send out to more systems) would be one way of spreading an inanimate presence throughout the galaxy quite quickly. The fact that we have not detected such probes is therefore a puzzle. _Somebody_ should have got around to doing it.

*They Do Not Exist*

Webb lists almost as many ideas under this heading, which to me represents the most interesting part because it is more solidly based in science rather than speculations about alien psychologies or the like. These explanations look at the sequence of improbable events which has led to our civilisation and argue that this sequence may be unique. 

There are several elements to this: first that the galaxy is a dangerous place, regularly blasted by intense bursts of gamma radiation from supernovae which would affect life for thirty light years around. The outer galactic zone in which the Solar System sits may be in the "Galactic Habitable Zone" (GHZ), a less vulnerable position than the more crowded central zone. The mysterious Gamma Ray Bursters (GRBs) are even more devastating; they could affect an entire galaxy and reset the evolution clock each time (for obvious reasons, they have so far only been observed in other galaxies). It is estimated that a GRB could happen in a galaxy like ours about every hundred million years, which would approximately match the frequency of mass extinction events on Earth.  So maybe we are among the first to achieve a technological civilisation since the last GRB wiped out any previous ones. 

The next point is that planetary systems are inherently dangerous. Catastrophic events such as asteroid strikes, supervolcanoes like Toba or other causes of wild fluctuations in the global climate may have led to many mass extinctions even without the help of GRBs or supernovae. Extinctions are a good thing very occasionally (we wouldn't be here without them) but cripple the development of life if they happen too often. Life may also require very particular circumstances in which to develop intelligence: obviously, any life like ours needs liquid water to be available for hundreds of millions of years, which means that the planet must be in exactly the right circular orbit (the continuously habitable zone, or CHZ) to achieve this even through various fluctuations in the sun's output. Finally, the tidal effects of one large moon plus the constant crustal renewal of plate tectonics may also be important elements in the conditions which led to us, although that is more speculative. 

Then we come on to the biological improbabilities. A key one identified by Webb is the development of multi-cellular eukaryotic life, compared with much simpler prokaryotic life such as bacteria. This was a remarkable event which took billions of years to happen – possibly, it's uncommon. So might be the development of intelligence at our level. Perhaps most significantly, of all of Earth life, we are the only one to develop the sophisticated language without which our civilisation could never have arisen, so this may be a very rare feat. And we cannot assume that every intelligent civilisation will be a technological one.

*The Author's Solution*

Webb makes clear at the beginning that in assessing the probabilities of ETCs developing, he is looking only at life "as we know it, Jim": based on carbon and liquid water. He acknowledges that there may be other forms of life, but since we know nothing about this, there is no basis even for speculating what it might be capable of. Anyway, that doesn't affect the basic problem that we have detected no indications of _any_ forms of life. 

Webb's conclusion, based on the arguments raised in the last section, is that we can't detect any ETCs because there aren't any – at least in our galaxy. (There are estimated to be hundreds of billions of galaxies in the universe, but the difficulties of communication and travel escalate by orders of magnitude if we try to include them; our own galaxy is big enough to grapple with!)

His view is that our complete failure to identify any signs of life elsewhere, when all the logic of Fermi's paradox suggests that there should be countless ETCs out there, probably with successive waves of expansion affecting the Earth, has only one feasible explanation – that we are alone. He works through several steps to justify this. First, he estimates that star systems in the galactic habitable zone make up only about 20% of those in the galaxy. Next, stars like our sun are needed to develop life as we know it; they make up only about 5% of the total. So we are down to only 1% of stars being suitable. Thirdly, a terrestrial planet needs to remain in an orbit within the continuously habitable zone for billions of years. He guesstimates that applies to perhaps only 0.1% of all planets (assuming 10 planets per star, that's 1% of the suitable stars). We are now down to about ten million such planets in our galaxy.

Now we switch from the potential for life to its actuality. How many of these ten million will support life? Webb guesstimates maybe half a million, of which 20% might suffer catastrophic extinctions; now we have 400,000. Factor in the number on which life progresses to the complex multicellular eukaryotic stage – he suggests one in forty – and we're down to 10,000. Then apply factors for tool use, high-level intelligence and complex language – and Webb believes we're left with just one; us.

*Your Reviewer's Conclusion*

Webb puts forward a well-reasoned case to explain why we might have the only technological civilisation in the galaxy. However, I still find his conclusion improbable. Obviously, this is purely a matter of subjective opinion – emotional prejudice, if you wish – as there is no hard evidence one way or the other. It is just that faced with the early development of life on Earth and its tenacity in colonising every possible environmental niche and developing a myriad forms of increasing complexity, I find it impossible to accept that, among the billions of star systems, we might be in the only one to have produced a technological civilisation.

My conclusion goes part-way with Webb, in that I think that while life may be very common, complex animal life may be very much less so; beings intelligent enough to develop technology far less still; and the actual development of a technological civilisation extremely rare. Just look at the history of our planet; simple monocellular life seems to have occurred quite early, perhaps less than a billion years after Earth's formation. But the oldest evidence for complex animals comes almost three billion years later. These rapidly developed to dinosaur levels of complexity, but then stagnated for hundreds of millions of years. Finally, through sheer luck, humanity evolved, but the earliest hominims were around for several million years before modern humans arrived about 200,000 years ago; and for 95% of those 200,000 years, our ancestors did nothing but live in hunter-gatherer packs, like clever animals. Our technological civilisation is the result of a long series of improbable accidents.

As a result of studying Webb's arguments, I am more pessimistic than I used to be about the chances of other ETCs developing. However, given that there are calculated to be 100 billion stars in our galaxy (that's 100,000,000,000), even if our planet was literally "one in a million" in producing a technological civilisation, that still works out as 100,000 ETCs. So where are they? The answer I favour is "not here now". Two different timescales need to be borne in mind: the age of the galaxy, and the probable lifespan of an ETC. Our own star is around 4.5 billion years old, compared with the average for our galaxy of 6.5 billion years (the oldest star being over 13 billion). So if we assume that it takes 4.5 billion years after star formation to produce a technological civilisation (the only example we've got), that means that other stars average a two billion year advantage over us – lots of time to produce a huge range of ETCs. But how long can these ETCs be expected to last? 

Just consider our situation again. We achieved the theoretical capability to communicate with other star systems only within the last century. Only half a century after that, we came dangerously close to wiping out our civilisation in a global thermonuclear war. Many scientists fear that over the next century or two we will have devastated our global environment to such a degree that our civilisation will collapse, giving us only a few centuries of possessing advanced technology. By definition, any civilisation with the technology capable of communicating with ETCs will develop the potential to destroy itself, one way or another. So perhaps ETCs just don't last very long. Suppose that the average is 1,000 years; multiply that by the nominal 100,000 ETCs mentioned above, and you get a total of 100 million "ETC years". Compare that with the 2 billion year average time advantage the galaxy's stars have over our sun, and you will see that an ETC will have been in existence for only about five percent of the last two billion years. So at any given moment there may be only a one-in-twenty chance of a single ETC existing anywhere in this galaxy. And no ETC would have the time to spread very far even if it wanted to; possibly none would ever manage to establish itself on another star system.

This is, of course, speculation built on speculation, but with a grand total to date of just one known example of a life-bearing planet to go on, that is bound to be the case. My vision is this: imagine if a camera could have been sited over our galaxy, filming continuously for the last few billion years, and recording each ETC as a bright flash. Then replay the film in quick time. I think we would see a huge number of ETCs sparkling all over the galaxy, from two billion years ago to the present. But slow the film down, and we may see only one flash at a time, with long pauses between them. Occasionally we might see two or more flashes occurring simultaneously, but on average they would be so far apart that communication between them would be highly improbable.

Webb didn't mention the Gamma Ray Burster problem in his conclusion, but if our galaxy is blasted by one every hundred million years or so, clearly many of the above calculations become rather academic. That could explain the silence all by itself.

*And another thing…*

A further point may limit the number of ETCs likely to be in existence at any one time. If an ETC is established on a planet and fails, for any of the reasons mentioned above, it may prove to be the one and only chance that planet ever has to establish an ETC. To understand why, just imagine the outcome if our present civilisation collapsed, leaving what would inevitably be a relatively small number of survivors existing at a subsistence level. Unless the environment had become irrevocably hostile to humanity, it is reasonable to suppose that some kind of recovery could be made, based on utilising organic resources such as wood to make carts, ploughs etc. The problem would arise with the switch to the mineral-based economy (metal processing and fuel) which, as far as we are aware, is needed to achieve an ETC – because the easily accessible mineral deposits have mostly been exhausted.  Even if our unfortunate successors knew where the remaining oil or metal ore deposits could be found, they would be unable to reach them without the advanced technology we deploy. It would be a classic Catch-22; they couldn't develop a technological civilisation without advanced technology! Perhaps they would find a different, non-mineral, route to a more sophisticated level of civilisation, but it seems highly unlikely that this would result in the technology needed to communicate with ETCs, let alone travel to them.

SF is full of beautiful dreams about humanity spreading through the galaxy and meeting other technological civilisations (or nightmares if they turn out to be hostile). Sadly, these are looking increasingly like fantasy rather than SF. I hope this is wrong, and that SETI will discover proof of ETCs, but I'm more pessimistic than I used to be. 

(An extract from my SFF blog)


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## K. Riehl (May 9, 2009)

I look at it as a problem of two civilizations reaching the point of interstellar communication _at the same time. _There may have been hundreds of ETC's that reached that point and then faded away over the last 100 million years. They may have developed a different way of communication, Ansible?, Tachyon?. They may be observing us to see if we survive to reach a technological/sociological point where they would contact us. Remember if we were using our current technology to look for ourselves we would only detect tranmissions since the early 40's. 

I am a early member of Seti@home but I realize that the chances are very small unless another species puts up a Banner/Communcation "we were here" that runs for millions of years.


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## ManTimeForgot (May 9, 2009)

The answer is "they are here" and they are too advanced for us to communicate with of _our own_ volition.  I hesitate to speculate on alien psychology: a "good" race might have something akin to prime directive, a "bad" race might not think we are even worth conquering, an "astoundingly advanced" race might not even realize/care (kind of like how we don't notice ants).  The simple fact is we don't know and have no way of knowing.  It might be some combination of all 3 by some kind of galactic accord...


But consider that every 10 years of scientific investigation yields a roughly 2 fold technological increase.  500 years difference yields a 1125899906842624 fold difference in technology.  That is of course presuming that rate of technological increase remains constant (no increase or decrease).  Yes, dark ages happen.  But so does renaissance (quantum computing might give us yet another renaissance).


Now when you consider that a billion years or so worth of life could have happened before us that is a lot of time to account for.  We live in a fairly remote portion of our galaxy.  The stars that are even close can't support any kind of life we are familiar with.  And the decades of communication we have sent out hasn't gotten to anything remotely interesting.  It is very possible that our nearest "galactic neighbors" are much further away.

This leaves us with the question of: Why aren't we seeing any signals?  If someone is in a position like us, then they could be on the other side of the galaxy entirely from us and the amount of time it takes for the signals to get here means that the signal is still coming.  And as far as their FTL communication/drives... how would we even know what to look for?  They could be using quantum improbability drives driven by mind force...  Does anyone have any idea what kind of effects engineering of that sort entails?  Heck, even if something was "relatively" close to us, there is no reason to think that diffuse communication would remain intact (space dust could be in the way), and communication just slightly more advanced than ours might take on more direct methods (laser/maser)...


Also consider some of the flaws in the Drake Equation: the rates and variability of planetary creation are pure guesswork at this point; the stars near a galactic core are far less likely to be habitable (hot, highly radioactive stars/area of space), and that doesn't even touch on what seems to be the case as most recent scientific advances have found that planetary systems like earth's solar system may not be all that common.

So the number of organic planets might very well be only a few hundred in our galaxy... and the number of planets which _held_ OR _hold_ intelligent life a handful.  Amongst those we might not be in a position to _receive_ anything from their days when they were close to our level of technology, and we are not in a position to _detect_ anything of 100 year tech advantage or greater.

MTF


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## Urlik (May 9, 2009)

Anthony G Williams said:


> If an ETC is established on a planet and fails, for any of the reasons mentioned above, it may prove to be the one and only chance that planet ever has to establish an ETC. To understand why, just imagine the outcome if our present civilisation collapsed, leaving what would inevitably be a relatively small number of survivors existing at a subsistence level. Unless the environment had become irrevocably hostile to humanity, it is reasonable to suppose that some kind of recovery could be made, based on utilising organic resources such as wood to make carts, ploughs etc. The problem would arise with the switch to the mineral-based economy (metal processing and fuel) which, as far as we are aware, is needed to achieve an ETC – because the easily accessible mineral deposits have mostly been exhausted. Even if our unfortunate successors knew where the remaining oil or metal ore deposits could be found, they would be unable to reach them without the advanced technology we deploy. It would be a classic Catch-22; they couldn't develop a technological civilisation without advanced technology! Perhaps they would find a different, non-mineral, route to a more sophisticated level of civilisation, but it seems highly unlikely that this would result in the technology needed to communicate with ETCs, let alone travel to them.


 
so what has happened to all the minerals we extracted and refined?
there is far more around on the surface than we've thrown up into space.
if neolithic man can work out how to work bronze, and bronze age man can work out how to work iron, then I'm sure these survivors can either find a source of ore or scrap to get them back to technology


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## Anthony G Williams (May 9, 2009)

Urlik said:


> so what has happened to all the minerals we extracted and refined?
> there is far more around on the surface than we've thrown up into space.
> if neolithic man can work out how to work bronze, and bronze age man can work out how to work iron, then I'm sure these survivors can either find a source of ore or scrap to get them back to technology


 
The basic metal needed for the industrial revolution was iron. Yes, there's lots of iron and steel on the surface, but they have a tendency to rust away...Other metals also oxidise over time. So the amount of salvageable scrap around will depend on how long it will be before the survivors are ready to move beyond the basic subsistence level. That can't be predicted as it will depend entirely on the circumstances.

And using scrap doesn't help with the lack of accessible coal and oil.


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## Nik (May 9, 2009)

'Where Are They ??'

Yeah, that seems a fair treatment of the possibilities.

IMHO, there's also the 'Horse Latitudes' effect...

IIRC, Sol and 'local loop' are in a low-density bubble blown by an inconveniently close super-nova. 

Assuming that 'c' limit and unobtanium stay that way, travel techniques seem limited to star-wisp, Daedalus' pulse and coast, or the constant-boost 'Bussard' ram-jet. Latter may be the only way to travel in style.

But, if you look at the interstellar densities, the gas within our bubble is far too thin for a practicable 'Bussard' to break-even, while the galactic region outside has about the right density...

IIRC, there's also a denser, if incomplete shell along the shock-wave's front. That would offer the equivalent of 'Trade Winds' to any space-faring culture on those arcs...

Meanwhile, we're stuck in the doldrums. Given a quarter-turn of the galaxy, a modest time geologically, Sol will have swung out of the bubble, and be accessible to such craft. That's assuming there's anything or anyone left to care...

Um, what happens when all easily accessible iron is mined out? Assuming we're still planet-bound, we'd have to resort to light alloys-- Aluminium from bauxite sands replenished by weathering from volcanoes, magnesium etc from salts extraction.

IIRC, bio-concentration should be able to retrieve useful iron from trace, eg GM reed-beds harvesting 'rusty streams', dry, coke & smelt.

And, as for the Ancients, some iron will continue to fall from the sky...

Some of the 'Palladium' group should be available by condensing volcanic vapours from several 'odd' Siberian RingOfFire fumaroles...


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## Nik (May 9, 2009)

*Slightly OT but relevant...*

Creating the astro-comb to locate Earth-like planets

quote:
Right now standard spectroscopy techniques can determine star movements to within a few meters per second (m/sec). In tests, the Harvard researchers are now able to calculate star velocity shifts of less than 1 m/sec, allowing them to more accurately pinpoint the planet's location. 

Smithsonian researcher David Phillips says that he and his colleagues expect to reach a velocity resolution of 60 cm/sec, and maybe even 1 cm/sec, which when applied to the activities of large telescopes presently under construction, would open new possibilities in astronomy and astrophysics, including simpler detection of more Earth-like planets.
/quote

Of course, if ETs look for cosy face-locked, tidal-warmed, terran-sized moons around gas-giants around red-dwarf stars, they'd ignore us completely...
;-)


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## Anthony G Williams (May 9, 2009)

Nik said:


> Um, what happens when all easily accessible iron is mined out? Assuming we're still planet-bound, we'd have to resort to light alloys-- Aluminium from bauxite sands replenished by weathering from volcanoes, magnesium etc from salts extraction.
> 
> IIRC, bio-concentration should be able to retrieve useful iron from trace, eg GM reed-beds harvesting 'rusty streams', dry, coke & smelt.
> 
> ...


If we're looking at a collapsed, subsistence-level civilisation then they're not going to be developing GM plants - and where would they get the vast amount of power to extract aluminium from bauxite?


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## zachariah (May 9, 2009)

These future survivors will be overjoyed when they discover their ancestors had the foresight to create giant reserves of materials, cleverly buried in easily accessible locations all over the world. We'll be regarded as the Wonderful People Who Left Us All This Stuff. 

In fact, they'll have a hard time figuring out why we dedicated our civilisation to creating these giant reserves.


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## skeptical (May 10, 2009)

There was an article in Scientific American about 10 years ago, written by a couple of NASA scientists (yes, Esmeralda - this *is* rocket science), on the subject of future star travel.

Their view was, that within 1000 years, using extensions of existing technology, humans would be able to travel to other star systems at 0.1 to 0.2 of light speed.

If we assume the lower figure, and assume that the time to accelerate to 0.1c is 10 years, and a similar time to decelerate back to zero, then it would take a space vehicle 55 years to reach our next nearest star - alpha Centauri.

I do not believe this to be anywhere near impossible.   Nor do I believe that humanity will lack volunteers for such a trip.  Quite the contrary.   The vehicle would have to be very large, and rotating for artificial gravity, to take a community so far.

Not do I believe that a habitable planet is needed at the final destination.   A civilisation representing humanity in 1000 years will have advanced technology - enough to convert even space debris into new space habitats, and use minerals and water from comets, asteroids, moons etc to provide all the resources needed for life.   In due course, the first explorers to alpha Centauri would create new habitats capable of crossing interstellar space.

If we then calculate how long it would take our advanced civilisation to colonise the entire galaxy, then depending on which assumptions we use, the figure is somewhere between a million and 10 million years.  This is also how long an extraterrestrial civilisation would take to colonise the *entire* galaxy.

About 10% of the star systems in our galaxy are about 2 billion years older than our own.   That means that 10% of any hypothetical extraterrestrial civilisations will have had a 2 billion year head start.  If they take 10 million years to colonise the entire galaxy, then we have to conclude that they have had heaps of time to do it.

A billion years ago, any expanding ET would have found Earth very appealing.   Primitive life.   Oxygen atmosphere.   No indigenous intelligences to compete for space.   Yet clearly no such intelligence ever landed and colonised.

We have recovered 500 million year old fossils of jellyfish - an animal soft and extraordinarily hard to preserve.   Yet we have *never* recovered so much as the ET equivalent of a coke bottle.  Why is this?


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## Nik (May 11, 2009)

"Yet we have never recovered so much as the ET equivalent of a coke bottle. Why is this ?"

There's several easy answers, even excluding 'What ETs ?':

First, we might not recognise such an artifact if we saw it, aka 'OutOfContext Error'.

Second, ET may have picked up their trash, carefully restricted disturbance to places that would be eg subducted and 'swept  under the rug'.

Third, statistically, fossilisation of any given individual is vanishingly rare. Only the sheer number of critturs dying in so many sudden ways has left us any traces...

When we get out among the stars, and *still* nothing turns up, no probes, wrecks etc, well, after a few milennia, we might then shrug...


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## Nik (May 11, 2009)

*Habitable zone piccy...*

Gliese 581 e Is The Lightest Exoplanet Discovered So Far

This link has a nice piccy with star masses from our Sun downwards and their predicted 'terrestial' habitable zone.


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## skeptical (May 11, 2009)

To Nik
Re ET coke bottle.

First, I think we are sophisticated enough to recognise an alien artifact as being 'out of place' in some ancient rock stratum.   We may not know what it is, or what it does, but we will know it is weird.

Second :  Re rarity of such items.   I am assuming that, over 2 billion years, that ET has not just visited the Earth, but set up habitation.   We know from looking at just one city landfill of the human variety that the amount of material is likely to be massive.  Fossilisation is rare - sure.  However, a colony of ET's on Earth would have left lots of stuff that is not readily degraded, and would easily fossilise.

My conclusion is that any visit by ET any time in the last 2 billion years would have to be fleeting, and very careful, to make sure all the trash was picked up.   It appears obvious that no colony ever was set up, and that probably means no visitors, since the Earth, after the appearance of an oxygen atmosphere, would have been such a plum for colonisation.

Another line of thought.   If we look at semi-intelligent life on Earth, we get an enormous variety of forms.   These range from squid and octopus, to crows and parrots, to cetaceans, to carnivores, and to apes.   And all these organisms share a common ancestry and many genes.

Imagine what the range of intelligent beings in the wider galaxy would be like!   The enormous range of forms, ways of life, ecological niches, habitats, and psychologies.   Since they do not share genes, or common evolution, the range would be probably beyond current human capacity to imagine.

Now assume that intelligent and civilised life is common in the galaxy.   The enormous range of ways of thinking and capabilities means that every approach to living in the galaxy would be tried.   Among that number, there would have to be a few good survivors who were aggressively expansionist.  Simple probability would dictate this.

So where are they?   Since it would take no more than 10 million years to colonise the entire galaxy to overpopulation, why are there no signs of that species and its civilisation?

My personal explanation runs alongside that of Stephen Webb.  That is :  intelligent life is rare in our galaxy.   There must have been very few, even over 100 billion star systems and 6 billion years of time.


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## Urlik (May 11, 2009)

Nik said:


> "Yet we have never recovered so much as the ET equivalent of a coke bottle. Why is this ?"
> 
> There's several easy answers, even excluding 'What ETs ?':
> 
> First, we might not recognise such an artifact if we saw it, aka 'OutOfContext Error'.


there are plenty of OOPArts and some of them could be ET's "coke bottle" but using Occam's Razor we rule out aliens and put them on the back burner until better examination techniques are developed to work out who made them and where they came from.



Nik said:


> Second, ET may have picked up their trash, carefully restricted disturbance to places that would be eg subducted and 'swept under the rug'.


good point and anything they didn't dispose of is covered in point 1



Nik said:


> Third, statistically, fossilisation of any given individual is vanishingly rare. Only the sheer number of critturs dying in so many sudden ways has left us any traces...


very true. in all the years that archaeologists have been digging up dinosaur bones, only 30 Tyranosaurus skeletons have been found and they were around for about 2 million years



Nik said:


> When we get out among the stars, and *still* nothing turns up, no probes, wrecks etc, well, after a few milennia, we might then shrug...


there is also the chance that their home planet has a gravity field that prohibited flight, let alone space travel.


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## Nik (May 11, 2009)

IMHO, we're within a decade of tech that could completely recycle *all* waste. Already, IIRC, there's plans for plasma-combustion facilities. 'Tame Grey Goo' nano-machines are not too far beyond. Then, building a 'melt down' self-destruct mode into disposables is almost trivial...

I'd also suggest that any space-faring society that lacked 'fast track' FTL must, perforce, recycle like crazy.

I agree with the caution on 'weird stuff': I remember the fuss over the preCambrian Edicarian finds, and the chagrin when fossils from several 'obviously different' species were eventually found to belong to same crittur...

Um, given the way a lot of our tech is becoming increasingly 'organic', and our environment is considered 'exceptionally metal-rich', an ET's discarded tech simply might not endure.

Other possibilities, I suppose, include anaerobic ETs trying to eliminate the mutant 'blue-green algae' that was pumping out toxic oxygen, but when even pounding the planet with big rocks etc failed...


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## ManTimeForgot (May 13, 2009)

skeptical said:


> To Nik
> Re ET coke bottle.
> 
> First, I *think* we are sophisticated enough to recognise an alien artifact as being 'out of place' in some ancient rock stratum.   We may not know what it is, or what it does, but we will know it is weird.
> ...



_Relevant text italicized and in bold:_

1) We are no where near sophisticated enough to recognize anything of the sort.  The difference 500 years of technology makes given a 2 fold increase every 10 years is astronomical.  A million year difference is so large I couldn't write it properly without scientific notation (it would take up my whole page).  Could you recognize an extra-dimensional pocket if you saw one?

2) Why should ET do anything of the sort?  Or rather why would they setup conventional habtitation?  Perhaps ET enjoys the 5th dimension better?

3) Humans aren't very good examples of aliens no are they?

4) So when all my technology is semi-organic or incorporated into the environment itself it wouldn't be set to bio-degrade or be incorporated into the genome proper?  Thats a heck of an assumption that ET with a 500 or more year tech advantage on us wouldn't want the most efficient and least environmentally interferring technology possible.


MTF


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## Nik (May 13, 2009)

*Planet hunter speaks out...*

The Crowded Universe

quote:
"A new space race is under way," Boss says at the outset of his book. The contestants in this race are NASA's Kepler mission and Europe's CoRoT (Convection, Rotation and Planetary Transits) mission, both of which have the potential to detect the first Earth-like planet around a distant star.

Boss is betting that together these spacecrafts will find not one but many Earths. He writes:

"If this bold assertion is proved correct by Kepler and CoRoT, the implications will be staggering indeed: it will suggest that life on other worlds is not only inevitable but widespread. We will know that we cannot be alone in the universe."

Mission control
Despite Boss' confidence in their success, Kepler and CoRoT did not start out as sure things. After the watershed detection of the first extrasolar planet in 1995, "the exclusive club of planet finders became increasingly crowded," and space agencies began seriously considering missions that would extend the planet search into space.
/quote

---
Um, I still remember when NO extra-solar planets were known and, worse, the few possible candidates suggested by tiny shifts on photographs turned out to be instrument artifacts.

Then there came HotJupiters, then came the 'zoo' extending down to 'giant earth' mass...

(Funny, I remember the very first 'planet formation' simulations published in eg Icarus journal routinely produced such zoos. IIRC, code was hastily tweaked to provide tidy, SolSystem-like arrangements-- At least occasionally !! I was really upset when our city's Central Library decimated the tech-journal subscriptions... )

I really, really hope the Euro-launcher flies okay. Could be a generation before any-one dares build another 'Great Observatory' if this flight fails...


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## Urlik (May 13, 2009)

it would be far better to build an optical interferometry telescope array in orbit and give it such a massive baseline that an earth sized planet would be visible.
build annother array in a matching orbit on the other side of the Earth and you might even be able to see signs of life on the surface of an Earth sized planet.

and just think of the pictures you'd get of distant galaxies and nebula
they'd blow the Hubble pictures out of the water


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## Urien (May 13, 2009)

"Where is everybody?"

Well fortunately the Vresh are now on "Twitter"... I'm a follower, their latest tweet says *"In Jupiter Space. We are coming. Die Earthlings Die."*

So I'm in my Mazerater Beam proof shelter as I write this. Oh here come's another tweet, it says *"Beware of what you wish for."*

Bye.....


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## Rodders (May 13, 2009)

Maybe this really is the unfashionable arm of the galaxy and no one's deigned to come here?


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## Nik (May 13, 2009)

"...build an optical interferometry telescope array in orbit ..."

Yup, one's planned. IIRC, it could, in theory, resolve continents and oceans (!!) on terrestial planets out to a dozen light years, piccy-quality equivalent to Mars seen by 'amateur' telescope...

Snags are *money* and *will*. If current and soon-launching instruments find wonders, then the next generation of instruments may be planned.

Also, if 'truly re-useable' launchers like Alan Bond's Skylon fly, assembling monster, multi-component optical interferometers is much more feasible. 

Unfortunately, the forthcoming Euro-launch puts two *very* expensive and potentially irreplaceable astronomy sats at risk. Cruelly, they could not afford to build spares or launch them separately...


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## Moonbat (May 14, 2009)

Is it possible that Aliens have visited Earth but just not in the last few hundred years, and so any tales of them are regarded as myths.

With the time scales we're talking about, Aliens could have visited over 50'000yrs ago and so there is no record of them. If it was several million years ago, still less information.

I think to assume that any advanced race would continue to grow (in population size) to the point where they collonise the enitre galaxy is a little pretentious. The difference between developed and developing nation's birthrates should show a decline as the society advances. (don't quote me on that, I'm clutching at straws)

For all we nkow there are other intelligent species in our own solar system but we don't recognise them as life yet. I heard a rumour that there were Women on Venus!


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## Nik (May 14, 2009)

"Women on Venus!"

They must be really, really HotBabes.

(Sorry, been a bad day, could not resist that one... ;-)


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## Hilarious Joke (May 15, 2009)

Very interesting thread!


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## skeptical (May 16, 2009)

My arguments on this topic tend to begin with the assumption that many people have - that is : that there are a lot of intelligent and civilised aliens.   Projecting that over several billion years into the past, and there must have been an awful lot of aliens. 

If we look at the obvious outcomes of there being a large number of alien civilisations (Drs Drake and Sagan calculated 1 million at any one time!), then we see that such a large number must have left traces.    If the number is small, on the other hand, the logical outcomes are very different.

If there are many such aliens, there will be enormous variability.   Thus, we cannot use arguments of the kind that go :  'perhaps they are stay at home philosophers.'   While some may conform to such a stereotype, some will not.   At least some will be highly expansionist.  

Even assuming a maximum travel speed of 10% of light speed,  and relatively slow reproduction and social development, an advanced and expansionist species will colonise the entire galaxy to the point of overpopulation in no more than 10 million years.   *If* intelligent aliens are common, then, over the past 2 billion years, at least one, and probably thousands, of such species will already have overpopulated the galaxy. 

In spite of arguments suggesting that such species will be the ultimate greens, and recycle everything, I cannot believe they could live on Earth (as opposed to a mere temporary camp) and not leave traces.    As I said, even such ephemeral beasts as jellyfish have left fossil traces.  

And when you get down to it, if an expansionist and colonising species got to Earth 400 million or more years in the past, why would they not colonise?   Why would they not reproduce in numbers?   It is *the* basic biological drive, after all.

The only good explanation for the lack of any traces of any intelligent alien, either here on Earth, or in a manner receivable by SETI, is that intelligent and civilised aliens must be in very small numbers.


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## ManTimeForgot (May 16, 2009)

So we are supposed to be able to recognize the consequences of bio-technology at least 500 years more advanced than us?  Not a chance, especially not if they didn't want us to.

60 years ago we could have flown a stealth bomber over the middle of the US and it would not have gone detected in the slightest.  If 50-60 years of tech difference results in an almost complete lack of detection what do you suppose several thousand years would do?  You fly an F15 over some primitive's island and you get "the gods visited us today."  Expose Man of 3,000 years ago to alien tech and basically nothing gets noticed: work of the gods.


Why would aliens waste resources by leaving it in space?  Even assuming it happened why would it be probable for it to have gotten to where we could find it?  We live in a fairly remote portion of the Milky Way.  And assuming we have been visited why would aliens stick around long enough for us to become advanced enough to recognize them for what they are?

MTF


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## Anthony G Williams (May 17, 2009)

*Re: Planet hunter speaks out...*



Nik said:


> The Crowded Universe
> 
> quote:
> "If this bold assertion is proved correct by Kepler and CoRoT, the implications will be staggering indeed: it will suggest that life on other worlds is not only inevitable but widespread. We will know that we cannot be alone in the universe."
> /quote


The problem with this kind of statement is that many people will read the last sentence as meaning "there are other intelligent, technological civilisations with whom we can communicate".

If Earthlike planets complete with liquid water and oxygenated atmospheres are found, I would be surprised if they were lifeless. But "life" may just mean bacteria....after all, that's all that lived on Earth for billions of years.


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## Anthony G Williams (May 17, 2009)

ManTimeForgot said:


> So we are supposed to be able to recognize the consequences of bio-technology at least 500 years more advanced than us? Not a chance, especially not if they didn't want us to.


You may postulate almost anything as being _possible_, but without evidence that is just so much hot air.

Given that *no* kind of evidence for the existence of extra-terrestrial civilisations has ever been found, it's a bit pointless speculating whether or not these theoretical beings might have visited Earth, if they ever existed.


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## Urlik (May 17, 2009)

skeptical said:


> Even assuming a maximum travel speed of 10% of light speed, and relatively slow reproduction and social development, an advanced and expansionist species will colonise the entire galaxy to the point of overpopulation in no more than 10 million years. *If* intelligent aliens are common, then, over the past 2 billion years, at least one, and probably thousands, of such species will already have overpopulated the galaxy.


 
given that it has taken life on Earth around 3.5 billion years to get from single cells to intelligent life, I find your estimate of 10 million years to completely colonise the galaxy as a trifle optomistic.



Anthony G Williams said:


> You may postulate almost anything as being _possible_, but without evidence that is just so much hot air.
> 
> Given that *no* kind of evidence for the existence of extra-terrestrial civilisations has ever been found, it's a bit pointless speculating whether or not these theoretical beings might have visited Earth, if they ever existed.


 
what if we have got the evidence for a vist from ETs but haven't recognised it as such?
I know most of Von Daniken's "evidence" has been disproved but his basic premise that ancient texts describing visitors from the heavens might be records of meetings with ETs isn't impossible.

Von Daniken's theories have been ridiculed because a lot of his "evidence" was dodgy, but that doesn't rule out the possibility that the ancients wrote what they saw and if the estimates for ETIs is close to accurate, then it is quite likely that that is what they did and that we have a written record of 1 or more visits but written by people who didn't fully comprehend what they saw


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## Nik (May 17, 2009)

IIRC, there was a 'Golden Age' SF tale that explained life on Earth as beginning with a leak in a long-ago visitor's waste-recycling system...
"Nothing to see here, move along, move along..."

IIRC, AC Clarke used a similar ploy to accidentally kill off the *only* ET-lifeform found within considerable search radius. The protean beastie raided the explorers' trash and was poisoned...

But seriously...

IIRC, our Sun / Solar Nebula mix is turning out to be of exceptionally high 'metallicity'. Having a leaner mix would really, really stack the odds against developing to space-faring ...

By rare happenstance, our Moon's formation by skew collision may have gifted the Earth with an unusually large core and thin crust, keeping the continents moving and 'dynamo' warm, while the Lunar tide kept the 'dynamo' wound. Active geology means a lot of minerals are rotated through our environment-- To where we can get at them...

I've hunted about, can't find the reference for this next possibility, so take it as speculation for now...

IIRC, Jupiter *eats* comets etc, and sweeps them from inner system. Our near-binary Moon has stopped a few in its time, especially around the 'Late Heavy Bombardment' stage...

Although tidal-stirred terrestial 'mega-moons' around gas giants in 'habitable zone' may be much more common than free-standing terrestial planets, those gas-giants may draw trouble upon their moons...

By this argument, 'Mega Moons' may make good brew-houses for primitive life, but they're not safe for long enough to evolve better. On the other hand, the safer terrestial planets tend to grind to a halt without tidal input...

---

Hopefully, the success of the new space telescopes and planet-finding techniques will help to unravel the extra-solar planets' zoo...


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## skeptical (May 17, 2009)

To Urlik, who thinks that 10 million years to colonise the galaxy is hopelessly optimistic.

On the contrary, that is my most conservative estimate - the upper limit.

If I were to get_ really_ optimistic, and suggest the *fastest* possible colonising of the galaxy, my reasoning would be as follows.

The NASA scientists I quoted earlier said that humanity, within 1000 years, will be able to travel between the stars at 0.1 to 0.2C.   Optimistically assume that our expansionist alien or human civilisation can travel at 0.2C.

Now assume that, starting with a technology equivalent to humanity in 10,000 years, over a period of another 10,000 years, this highly advanced civilisation makes 100 billion space craft.   Each is controlled by computers and robots of advanced design, and carries a cargo of frozen embryos along with all the equipment and software to thaw them, incubate them in artifical wombs, and raise them to an educated adulthood.  Granted that such an effort would require a civilisation totally obsessed with galactic colonisation - but I am going here for the *most* rapid expansion possible.

The space craft are fired off to all the stars in the galaxy.  The slowest trip would be to the opposite side of the galaxy.   Assuming a 'direct' route was followed, that journey would take 350,000 years approximately. Once arrived, the computers/robots would need to be able to manufacture habitats for people from the detritus of the star system - asteroids, comets, small moons etc.   This because habitable planets would be few and far between, most likely.

Assume 'normal' reproductive rates, allowing a doubling of the population each 50 years.   If the colonising vessel holds 1000 embryos (fewer would carry the risk of later inbreeding) then the population would be more than 100 billion in 1500 years.

Thus, the galaxy could, in theory, be colonised to the point of overpopulation in less than 400,000 years.

I am not seriously suggesting this, of course.  Many of the assumptions for such rapid colonisation are a bit questionable.  Thus, I present the very conservative figure of 10 million years.   The reality is that total galactic colonisation most likely would take a period somewhere between those extremes.


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## Urlik (May 17, 2009)

skeptical, I suggest that 10 million years is optomistic because other life forms aren't starting out with a tech level 1000 years more advanced than ours.
they'd start out the same as life on Earth and take 3 or 4 billion years to get to that level.

so regardless of how fast they can travel across space, it would still take them in excess of 3 billion years


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## Anthony G Williams (May 17, 2009)

Urlik said:


> what if we have got the evidence for a vist from ETs but haven't recognised it as such?


If we haven't recognised it, then by definition it can't be evidence.

Evidence is what you can show to other people to convince them of its reality.



> I suggest that 10 million years is optomistic because other life forms aren't starting out with a tech level 1000 years more advanced than ours.
> they'd start out the same as life on Earth and take 3 or 4 billion years to get to that level. so regardless of how fast they can travel across space, it would still take them in excess of 3 billion years


 
As I pointed out in the first post of this thread, the stars in our galaxy are, on average 6.5 billion years old. Our sun is 4.5 billion. So if it takes 4.5 billion years to develop a technological civilisation, other star systems have on average a 2 billion year advantage over us (some will of course be far older - the oldest star in our galaxy is about 13 billion years). So there has been plenty of time for any extraterrestrial civilisations to develop and colonise the galaxy -  thousands of times over. The fact that no evidence has so far been found anywhere (in space or on Earth) for any such civilisation raises some fundamental questions, which I address in the final part of the first post.


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## Urlik (May 17, 2009)

Anthony G Williams said:


> If we haven't recognised it, then by definition it can't be evidence.
> 
> Evidence is what you can show to other people to convince them of its reality.


ok, I should have said "potential evidence".
as an example, until the late 19th century fingerprints were not recognised as evidence but that doesn't mean that criminals prior to this time left no fingerprints. they did but they weren't recognised as evidence.
we may have evidence of ETI visits all around us but because it has always been there we fail to recognise it for what it is.



Anthony G Williams said:


> As I pointed out in the first post of this thread, the stars in our galaxy are, on average 6.5 billion years old. Our sun is 4.5 billion. So if it takes 4.5 billion years to develop a technological civilisation, other star systems have on average a 2 billion year advantage over us (some will of course be far older - the oldest star in our galaxy is about 13 billion years). So there has been plenty of time for any extraterrestrial civilisations to develop and colonise the galaxy - thousands of times over. The fact that no evidence has so far been found anywhere (in space or on Earth) for any such civilisation raises some fundamental questions, which I address in the final part of the first post.


 
that is similar to what I was saying.
a civilisation capable of exploring the galaxy isn't going to do it in 10 million years. it is going to take 3 or 4 billion years longer than that for the planet to form and life to evolve to the point where galactic exploration is possible.

another point to consider is what size planet is most likely to support life?
if the Earth is towards the lower limit, many potential galactic voyagers might never get off their planet due to the greater effect of gravity.


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## Anthony G Williams (May 17, 2009)

Urlik said:


> a civilisation capable of exploring the galaxy isn't going to do it in 10 million years. it is going to take 3 or 4 billion years longer than that for the planet to form and life to evolve to the point where galactic exploration is possible.


I took the "10 million years" as starting from the beginning of interstellar travel - in other words, an advanced technological civilisation would already have to be in place.


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## Urlik (May 17, 2009)

fair enough 

another point to consider is what type of star is most likely to have planets capable of life?
would they be the older stars that have several billion years head start on us or would they be the younger stars like our Sun?


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## Anthony G Williams (May 17, 2009)

A very difficult question to answer, as we only have one example of a planet which has developed a technological civilisation!

Some stars are not stable enough, for long enough, to allow the billions of years of reasonably consistent planetary conditions necessary to develop advanced life. That seems to be the main limitation, although there may well be others.


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## Urlik (May 17, 2009)

after having a bit of a read, it appears that many of the older stars aren't metal rich like the Sun and are unlikely to have formed accretion disks.
the majority of these older stars also occupy a region close to the Galactic Hub and would be heavily dosed with radiation.
if this is the case, then stars capable of forming Earth like planets are likely to be among the younger stars like our Sun.
this would reduce the head start of any potential ETIs in colonising/exploring the galaxy.


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## zachariah (May 17, 2009)

There ain't no justice
There's just us.

I'm amazed nobody's motivated to go to the expense of making a real generation ship, with the prize of your own planet waiting at the other end (for your descendants). I'd sign up!


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## Urlik (May 18, 2009)

well it is a huge expense and until we find at least a few likely candidate planets, firing a generation ship off into the void isn't practical.
the ship will need a lot of fuel to go into orbit around any planets they pass, then if that planet isn't suitable, they will need to get back out of orbit and up to a reasonable velocity again.
this will require, for a ship large enough to class as a generation ship, a huge amount of fuel.
get the fuel allocation wrong and, instead of a ship and crew colonising the galaxy, we end up with an artificial comet with an organic core.


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## Anthony G Williams (May 18, 2009)

I can't see anyone sending a generation ship until robot probes have identified a suitable planet. There will then be a debate about the ethics of taking over a planet which, if suitable for humans, will almost certainly already have life.

I'm not sure that generation ships make much sense anyway, because of the vast size and resources required, plus the worries already covered in SF about what could happen to the social organisation of the ship by the time it arrives. A ship transporting frozen embryos, as already suggested, would be the most efficient way of "seeding" a planet, with a few crew who would perhaps travel in frozen sleep themselves, if that becomes possible.


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## skeptical (May 18, 2009)

On the subject of generation ships.

Again, basing the following on my earlier SciAm article.   Assuming that, within 1000 years, humans can make starships capable of travelling at 0.1c, and assuming 10 years to accelerate to that speed, plus another 10 years to decelerate back down, then...

A journey to the closest star (apart from Sol) would be to Alpha Centauri at 4.5 light years.   This would take 55 years.

Tau Ceti is an Sol-type star just under 12 light years away.   Under the same assumptions, it would take 130 years.

Extend the time frame for the voyage to 200 years, and humanity has access to a hundred star systems.  Go to a thousand years, and we have access to literally tens of thousands.  I think that, within 10,000 years, our species could well have colonised hundreds of thousands of other star systems.

Over a sufficiently large time frame, the fact that light speed cannot be exceeded will not stop humanity, or some hypothetical alien civilisation, from colonising the galaxy.


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## ManTimeForgot (May 18, 2009)

I don't think you all have really heard what I have been saying so far.


Why do you all assume that ET is going to bother to "colonize" a bunch of useless star systems with nothing in them, when the fifth dimension or 29th dimension or whatever is SO much *COOLER!* 

We are _children_ or not even, ants really, when it comes to our view of the universe and reality and whatever else.


Aliens are not going to think like us.  They are going to think nothing like us.  Logic and mathematics might be the only common ground we have at all, and our understanding of those might be so woefully incomplete as to make us not worth bothering with.  Our brains are barely able to conceive of non-linear causation let alone think in those terms.  We, as society, still look at the universe and greater reality with a "human-centric" view of things.


Looking for evidence of gods (which is what the difference of several thousand or heaven forbid million or billion years amounts to) is ludicrous on its face, and if that isn't immediately obvious to you, then I don't really know what to tell you.


Perhaps we will find the remains of civilizations of 500 year differences (or so) from back when they stomped around the galaxy.  Perhaps we will find such a civilization that is currently active.


But right now we live in an isolated sector of space, playing in the universe's equivalent of the children's sandbox.  Adults don't play in the children's sandbox at playgrounds.  Adults that do that end up stepping on children if they aren't careful.  Responsible adults don't want to have to deal with the consequences of a mistep.  And irresponsible adults are going to leave enough traces (read conquest or galactic mistakes) as to get in trouble with the responsible adults.



We are _Not_ ready.

MTF


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## Anthony G Williams (May 18, 2009)

skeptical said:


> On the subject of generation ships.
> 
> Again, basing the following on my earlier SciAm article. Assuming that, within 1000 years, humans can make starships capable of travelling at 0.1c, and assuming 10 years to accelerate to that speed, plus another 10 years to decelerate back down, then...
> 
> ...


I don't think that you're considering the psychological and cultural effects of multi-generation ships. 200 years is 8 generations, brought up entirely within the relatively tiny confines of a ship. After the first couple of generations, there will be no-one alive who ever walked on Earth - they will only have films and fables to go on. What kind of shifts in culture will there be? Will they come to doubt the reality of Earth, and regard it as a fairy story? When they arrive at the target planet, will they have any interest in leaving the safety of their ship, which is all they've ever known? (I expect that agorophobia would be a major problem).

Issues like these have been dealt with several times in SF stories, which sometimes shows the crew descending into savagery. The fact is, no-one knows what would happen to them, brought up in such an environment for generation after generation.


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## Urlik (May 18, 2009)

ManTimeForgot said:


> Aliens are not going to think like us. They are going to think nothing like us. Logic and mathematics might be the only common ground we have at all.


 
even if logic and mathematics are the only common ground (although I would expect physics and chemistry to be in the mix as well) it doesn't take a genius to work out that a planet has a finite amount of living space and isn't the most stable of places to live (99% of all species that have ever lived on Earth have been made extinct due to everything from meteor impacts through volcanic activity to climactic change) and will know that their only hope for species survival is to put some of their eggs in a different basket (colonise another planet)



ManTimeForgot said:


> Looking for evidence of gods (which is what the difference of several thousand or heaven forbid million or billion years amounts to) is ludicrous on its face, and if that isn't immediately obvious to you, then I don't really know what to tell you.


 
no-one is looking for evidence of gods, but if a technologically primitive civilisation of our past was visited by an advanced civilisation from another star system, the accounts of that meeting (from the primitive view point) would read pretty much like most of the early religious texts.
if it is ludicrous to look for the origins of the myths and legends then, by that logic, it is also ludicrous to research our past in any way.

it is ludicrous to say that if we were visited there would be some evidence and the dismiss out of hand any and everything that could be that evidence.

even the creation described in Genesis could be interpreted as alien intervention given that ET could clone himself (create man in his own image) then take another tissue sample, remove the Y chromosome and replace it with a duplicated X chromosome to give male and female of the species.

*NOTE *I am not saying that this is what happened, but I find it interesting that several thousand years ago technologically primitive man described something that has only recently been found to be possible.
this doesn't mean that everything in all ancient texts should be taken as 100% true (owing to translation errors and a game of chinese whispers stretching over millenia) but as some historians and archaeologists have discovered, many myths and legends have some basis in fact.
the Illiad and the Odyssy talk of a city/state called Troy and an archaeologist followed the directions and found the remains of a city in the right place. this could be a coincidence or it could be that there was a Trojan war and the stories were basically true with some embelishments added through retelling. take WW2 as an example. we know it happened and that there are many interesting and exciting things that did happen, but the popular image we have of WW2 today is from films like Saving Private Ryan where the setting and the main events are real but the personal story is fictitious. just because there was no Private Ryan doesn't make WW2 fiction.
another interesting find made after following the directions from a myth was that when the course plotted in the story of Jason and the Argonauts is followed it leads to an area where fleeces are thrown into a river to collect gold dust then hung on a tree to dry. much of the story is embellishment but there is a grain of truth behind it.
the question this raises is are there similar grains of truth in any other myths, legends or religious texts?
if we follow this question to its conclusion we get the question what inspired so many ancient peoples around the world to write accounts of visitors from the stars?
if those accounts have some factual basis then the chances are that we have been visited but the evidence we have for it is being overlooked due to a polarisation regarding those texts (those that follow them as religious texts don't want a mundane explanation of the events described and those that don't believe class them as superstition and unworthy of research) and the embellishments and mistakes added over the years.


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## ManTimeForgot (May 18, 2009)

Urlik what you are describing isn't impossible.  And I am glad that you are keeping an open mind.


But please keep in mind the distinction I am drawing here.  Technological advantage is an exponential difference.  A civilization within 500 years of what we are now is conceivably detectable.  It may very well be something accounted for in some of the older mythologies and legends.  But what I am talking about is something a little different.


Civilizations within the range of detectability (something close relatively speaking to what we have and can conceive of now) might very well be _allowed_ to visit primitive planets.  But there is no way they would continue doing so _now_ without trying to go undetected; that's dangerous for a variety of possible reasons (some of which is undoubtedly correct assuming they are even still interested in our sector of space; which they may not be).

That doesn't touch on a civilization a 1,000 years or more advanced on us from what we have now.  That kind of technology is so far beyond us as to be beyond our wildest dreams.  String manipulation?  We are talking about gods Urlik; no other name really suffices for our conception.  Practical string manipulation and you could reshape any particle, energy, space, time, or anything into whatever you wanted.  Every wondered what happens when you convert matter into time and then shunt it across space?  Probably not (I certainly haven't), but such a race could do it for all that that means anything to us now.  And such a race wouldn't be able to be detected by us unless they forced us to.


MTF


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## Urlik (May 18, 2009)

I think that while string theory is the best hope for a Grand Unified Theory that ties Newton's Gravitational theories in with Relativity, we still don't have any way of really comprehending it fully.

we don't know if the extra 6 or more dimensions work the same as our 3 spatial dimensions or whether they are more like time or even Einstein's SpaceTime.

we can't assume that a civilisation even a billion years more advanced than us is able to operate in more dimensions than us unless they originated as pan dimensional beings.
the reasons for this are many.
let us imagine a 2 dimensional being (with dimensions along the x and y axis) living on a flat plane (with dimensions along the x and y axis)
what possible tool or instrument could the 2 dimensional being create to manipulate an oblect along the z axis that he can't even observe directly (even if he can deduce its existence through indirect observation)?

if there are pan dimensional beings then their tech level is irrelevent as no matter how far advanced or not they are, they started out with the ability to operate in more than 3 spatial dimensions.
if they aren't pan dimensional (and for the purposes of this thread they aren't as we are dealing with "life as we know it Jim") then even if they are aware of other dimensions (through indirect observation) it is probably impossible for them to create tools to manipulate more dimensions than those they can interact with directly.



> Civilizations within the range of detectability (something close relatively speaking to what we have and can conceive of now) might very well be _allowed_ to visit primitive planets.


allowed by whom?
if our history had taken a slightly different route and the Mongols had subjugated the world but technology had advanced a little faster, who would tell the Great Khan that his ships couldn't visit a primitive planet or even one as advanced as ours (ours being the most advanced we have definite knowledge of)?
the cosmos doesn't have a police force or army setting up blockades and border controls, so who gives this assumed permission?


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## Ursa major (May 18, 2009)

I feel like saying: "Gort help us!"

Even if there are "rules", that does not mean that they would be obeyed. (We have International rules here on Earth, and most if not all countries have broken at least some of them, even countries with little or no apparent power; and that's without considering individuals and groups who operate outside their country's laws.)

If there are rules, rules that _can_ be enforced, we are really talking about a single political entity, however many species and civilisations there are under its laws. A political entity which is that powerful has no need to obey its own rules all the time. (Who is going to force it to?) Unless, that is, we think that a state with very advanced technology is bound to be populated wholly by beings who are totally virtuous.


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## mosaix (May 18, 2009)

Here's an interesting thought:

Life started on Earth millions of years ago. Why, during that time, hasn't life started again? Why no second chain of evolution?

Possibilities:

1) The start of life is such a rare event that it only happens once in millions of years.

2) The conditions for the start of life no longer exist here.

3) It has started again but we haven't noticed.

Any others?

We are so busy looking for life elsewhere that we don't seem to wonder why it hasn't happened again - _here_. Surely, life starting once shouldn't preclude it starting again - so why hasn't it? The answer may help us understand why we aren't seeing it elsewhere.


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## Nik (May 18, 2009)

IMHO, #2 includes the 'founder effect', here 'winner takes it all'...


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## Urlik (May 18, 2009)

I'd guess at 2 or 3

maybe some of the new bacteria and viruses are the result of life starting again rather than mutation


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## Ursa major (May 18, 2009)

It's hard to say, Mosaix.

Just a few thoughts:

One of the things life seems to do is alter its environment, which might help to stop new life creation. Life also adapts, which might mean that an organism more or less perfectly adapted to where it lives would have an immense advantage against a newly created one. (It strikes me that this might not necessarily lead to the complete destruction of any new life.)

It may be that in the range of conditions found on the Earth, the types of possible new life might be quite narrow. This might mean that life _did_ start more than once, but that we would be unable to tell which was which because, say, they all use the same sort of biochemistry. (Later changes to the Earth's environment might have put a stop to this process.)

It may be that life has very strict biochemical rules, so that however varied the environment, it might appear to have the same genesis. (And if the environment could not support that type of genesis, there would be no new life.)


I don't know how far back scientist can "look" when they examine DNA to look for historical changes and the rate of change. I'd imagine it all gets rather confusing as you go back and (hopefully) approach the genetic ancestor. And if all the various new forms of life evolve, there may be a degree of convergent genetic evolution, further blurring the distinctions between what were independently generated genetic lines.


So we either need a time machine or a long chat with a species that has access to records that go back that far.


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## skeptical (May 18, 2009)

To mantimeforgot

When you take the tack you have, you are going way out into woowoo land.  A highly advanced civilisation still has to work within the laws of physics.   Sure, they will develop all sorts of tricky ways of using the laws of physics, possibly including some laws that we have not discovered yet.   However, their technology will be limited by those laws, just as ours is.   For example :  they are seriously unlikely to be able to travel faster than light.    They will drink their fluids from cups or some variation on the cup or bottle theme.   

They will probably not be able to move to other universes, or through extra dimensions.   There is no known theoretical means by which such can be achieved.  While this does not mean that a method may not be discovered, it certainly reduces the likelihood.  When speculating, better to stick to known scientific theory than to enter the world of magic and fantasy.

Anthony
Re the psychology of generation ships.   I think you may be denigrating the human ability to adapt.   There is no animal that is as plain adaptable as _Homo sapiens_.  And that is especially true of social adaptation.   Put a bunch of chimps together in a crowded space and there will be massive violence.   Yet 100,000 humans can crowd together in a sports stadium, under conditions of incredible emotional outpourings, yelling at the top of their voices with sheer passion, and if accidentally banged on the head by another person's waving arms, will accept a simple "sorry" and continue with no violence.

We stand in en elevator so crowded that we cannot lift our arms, and accept it with equanimity.   Humans are really amazingly good at social adaptation.   I have no doubt at all that, with a bit of good ship design aimed at releasing social tension, any number of generations could live aboard a generation ship, and get along well.

I do have a bit of a twist on this, though, compared to standard SF stories.   I think that the adaptation may go too far.   If a few thousand people live on a generation ship for 10 generations, then when they get to their destination, they may not be real happy about going down to live on a planet, especially if said planet is not comfortably habitable.   I think that they may end up building habitats in space to live in.   After all, assuming fusion power, and unlimited minerals and water  on asteroids, comets and small moons, there will be plenty of resources to do just that.   It would not surprise me if humanity in the medium distant future did not, as a majority, become 'space dwellers'.

Instead of a Dyson sphere, star colonies may take the form of millions of space cities - enormous rotating cylinders in stellar orbit, each with an outer shell of water ice for radiation protection and as a resource for normal use.  Indeed, with fusion power, such habitats or cities need not hug the star - but cruise through the stellar equivalent of Oort Clouds, collecting essential resources.

Once humanity leaves the solar system, they may find that the galaxy is an enormous resource filled space, capable of supporting enormous numbers of humans in a state of high civilisation with a standard of living we cannot even dream about today.

Which again begs the question :   with 10% of the star systems in this galaxy 2 to 3 billion years older than ours, why is the galaxy not already filled with such a civilisation, or civilisations?


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## Urlik (May 19, 2009)

skeptical said:


> Which again begs the question : with 10% of the star systems in this galaxy 2 to 3 billion years older than ours, why is the galaxy not already filled with such a civilisation, or civilisations?


 
I did briefly cover that in an earlier post



Urlik said:


> after having a bit of a read, it appears that many of the older stars aren't metal rich like the Sun and are unlikely to have formed accretion disks.
> the majority of these older stars also occupy a region close to the Galactic Hub and would be heavily dosed with radiation.
> if this is the case, then stars capable of forming Earth like planets are likely to be among the younger stars like our Sun.
> this would reduce the head start of any potential ETIs in colonising/exploring the galaxy.


although that last line should have read "reduce the head start of *m*any potential ETIs in colonising/exploring the galaxy"

other factors to take into consideration are all those surrounding evolution.
if the planet is too stable it might never develope higher life forms as the conditions won't generate the necessery impetus for evolution. although the planet would be included within the percentage of planets capable of supporting life, evolution might never get off the first rung or might take billions of years longer than it has on Earth.
one example of this is HSP90 (a heat shock protein)
it's main function is as a chaperone to ensure that other proteins fold correctly, masking mutations and variations within the protein, but when streesed, instead of assisting in protein folding, HSP90 protects the cell from the elevated temperatures.
this allows the previously masked mutations and variations to be expressed.
this is one of the ways in which evolution gets to "try out new ideas" and see which could work for an unprecidented environment and seeing how they compete against others within that environment for resources.
if the environment is stable then proteins like HSP90 do the job of chaperone and mutation/variation is suppressed.


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## skeptical (May 19, 2009)

To Urlik

That is a nice intelligent post.   Good to see someone with a bit of thought.

Couple of comments.
First, when I talk of 10% of the galaxy being 2 to 3 billion years older than our own star system, I mean third generation stars.   That means that any planets they have should be reasonably metal rich.  

I agree with your other ideas, in that we do not know what characteristics of a planetary system are required for evolved life, though I think it is more likely that stability is needed for life's development - rather than the instability you mention.  

Here on Earth, we have some special features that might be needed.   
For example :  we have a nearly circular orbit - whereas most extrasolar planets have a much more elliptical orbit, that should lead to climatic extremes - possibly too extreme for life.  Liquid water is probably essential for life, and a stable climate means liquid water is always available.

We have a massive moon - unique in our own system - that stabilises through its gravity the Earth's 'wobble', thus leading to an even more steady climate.

We have plate tectonics, permitting formation of land structures that might be needed for life.   One theory is that life began in hot springs.  If so, planets without plate tectonics, vulcanism, and hot springs, could not generate life.  Mars, for example, does not show plate tectonics.

We have no large planets close to the sun, but one further out (Jupiter) in exactly the position needed to 'sweep' up debris, and reduce very dramatically the number of damaging asteroid impacts on our planet.

Our planet has exactly the correct magnetic field for shielding us from cosmic rays.

There may be many, many other requirements for life, making Earth nearly unique.


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## Hilarious Joke (May 19, 2009)

> Good to see someone with a bit of thought.


 
That's a little unfair. I think everyone's put thought into their posts. None of us can be expected to be absolute experts on all the topics involved in this discussion, and I don't think that should preclude anyone from having their two cents.


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## TheEndIsNigh (May 19, 2009)

> Ursa:
> 
> Unless, that is, we think that a state with very advanced technology is bound to be populated wholly by beings who are totally virtuous


 
Yeah right.

We don't even give that quality to our own imagined deities so why would real "extra terrestial gods*" be expected to act that way

*gods in the sense they would appear that way to us. Just as western technology  appeared that way to remote civilisations in the 'way back when' times


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## ManTimeForgot (May 19, 2009)

Sceptical:

You certainly have quite the conceited notion about our understanding of the universe or even greater reality.

Ask any honest scientist and you will learn that what we know about the universe is so far eclipsed by what we don't know that if you divided what we do know by what we don't you get *ZERO.*


Alien technology of 500 years advanced is (given the median estimate of two-fold increase in technological ability every 10 years) a 1,125,899,906,842,624 (that's 1 quadrillion for ease of reading) fold increase in technological ability.  A difference of that magnitude is completely incomprehensible to us.  Anyone who seriously thinks that ET's technology is going to be anything other than magic to us is so arrogant and human-centric as to be living in a state of complete ignorance.


TEIN hit the nail on the head: gods is what they would appear to us to be; as our level of technology does to some remote primitive civilization on some backwater portion of the planet.  The problem you seem to be having is that right here, right now we are the backwater portion of the universe and that remote primitive civilization is _us..._


ET certainly will be "limited" by the laws of physics just as we are.  The problem here is their "limitations" and ours are not even close to being the same thing.  ET can't do anything which is logically contradictory, and that's about the best we can say.  So ET cannot use gravity and not use it simultaneously, but there is no reason to think that ET with quadrillions times better tech and scientific understanding couldn't simply ignore gravity when they choose.  What exactly does gravity do for someone who traverses the 29th lateral concommitant dimensional plane (no idea what that is; totally making it up, but for sake of argument magic and quintillion tech is the same thing)?  I have no clue what-so-ever, and I don't pretend to know.

ET's abilities are so wildly beyond our reach as to be utterly inconceivable.  We might find the remnants of a civilization that once was at where we are now or somewhere close; if we are lucky will even meet one close to us in technology some day.  But thinking we are going to strike the pan-galactic lotto by finding quintillion tech in our "galactic back yard" doesn't even approach wishful thinking.

MTF


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## mosaix (May 19, 2009)

Hilarious Joke said:


> That's a little unfair. I think everyone's put thought into their posts. None of us can be expected to be absolute experts on all the topics involved in this discussion, and I don't think that should preclude anyone from having their two cents.



You took my very words HJ.


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## mosaix (May 19, 2009)

skeptical said:


> Yet 100,000 humans can crowd together in a sports stadium, under conditions of incredible emotional outpourings, yelling at the top of their voices with sheer passion, and if accidentally banged on the head by another person's waving arms, will accept a simple "sorry" and continue with no violence.



And yet, on the other hand, outside the stadium kick the crap out of someone because he happens to be wearing a red shirt instead of a blue one or has black skin instead of white.

I think you are right, skeptical for most of humanity but a small minority have the capacity to a) ruin it for the rest of us and b) persuade a sizeable proportion that their intolerant views are correct, hence the rise of the BNP in British society during times of stress.


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## Urlik (May 19, 2009)

Skeptical, when I said that a planet could be too stable for the evolution of higher life, I meant that if it didn't have plate tectonics and vulcanism and extreme climate variation (which Earth does have) then there wouldn't be the impetus (and possibly the mechanism) for evolution to progress beyond the start of life or it would be slowed down dramatically and even though a system could be 2 billion years older than ours, life on the habitable planet is evolving at a much slower rate than here and some fish are only just starting to flop about on mud flats to avoid predators.

if we look at evolution on Earth, since the last major change in climate evolution has settled down (although it hasn't stopped, even in humans. records of teeth show that modern humans have smaller teeth and some adults have no wisdom teeth at all, as we eat processed food and as our jaws get smaller, there is no need for large teeth or room for wisdom teeth) but if we look in areas where the environment is rapidly changing we get lots of organisms evolving.
we have antibiotics but we constantly hear about new bacteria that are resistant to treatment. the popular news calls these mutations** but in reality they have evolved to live within the new environment that we have created for them.


**this could be because Creationists will accept that a bacteria can mutate but won't accept that it can evolve, so it is easier to say mutate and get newspaper sales rather than say evolve and get nasty letters. mutate is also a good scare word which looks good in headlines, which also helps sales


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## Ursa major (May 19, 2009)

mosaix said:


> but a small minority have the capacity to ... ruin it for the rest of us....


 
Exactly.

And a few aliens of this sort with quintillion tech (to borrow the term MTF used) might think nothing of making all our lives into a living hell and would have the capability to "achieve" it.


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## zachariah (May 19, 2009)

Maybe they have already.


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## Urlik (May 19, 2009)

ManTimeForgot said:


> Ask any honest scientist and you will learn that what we know about the universe is so far eclipsed by what we don't know that if you divided what we do know by what we don't you get *ZERO.*


that is a false argument.
we don't actually know how much we don't know. if we knew how much, then we'd know what we were missing and have a pretty good idea what most of it was (the basic shape at least even if we didn't know the details)



ManTimeForgot said:


> Alien technology of 500 years advanced is (given the median estimate of two-fold increase in technological ability every 10 years) a 1,125,899,906,842,624 (that's 1 quadrillion for ease of reading) fold increase in technological ability. A difference of that magnitude is completely incomprehensible to us. Anyone who seriously thinks that ET's technology is going to be anything other than magic to us is so arrogant and human-centric as to be living in a state of complete ignorance.


that is assuming that technology has the potential to progress infinitely.
we know for a fact that technology increased at a much slower rate for tens of thousands of years in our history. right now we are having a growth spurt, but we don't know for sure that it will continue.
in some areas it isn't progressing at that rate and in others it has virtually stopped.
for all we know, technology might reach a plateau in the next century and there will be no more advancements.



ManTimeForgot said:


> TEIN hit the nail on the head: gods is what they would appear to us to be; as our level of technology does to some remote primitive civilization on some backwater portion of the planet. The problem you seem to be having is that right here, right now we are the backwater portion of the universe and that remote primitive civilization is _us..._


Clarke's 3rd law again, but taken with my above point about the possibility that technological advancement is a finite process along with the fact that our solar system lies within one of the best regions of the galaxy for supporting life, we may find that we are among the more technologically advanced intelligences in the galaxy rather than the primitive (although this doesn't mean that we have never been visited in our past but the tech level of those visitors may have already reached the plateau that we are approaching)



ManTimeForgot said:


> ET certainly will be "limited" by the laws of physics just as we are. The problem here is their "limitations" and ours are not even close to being the same thing. ET can't do anything which is logically contradictory, and that's about the best we can say. So ET cannot use gravity and not use it simultaneously, but there is no reason to think that ET with quadrillions times better tech and scientific understanding couldn't simply ignore gravity when they choose. What exactly does gravity do for someone who traverses the 29th lateral concommitant dimensional plane (no idea what that is; totally making it up, but for sake of argument magic and quintillion tech is the same thing)? I have no clue what-so-ever, and I don't pretend to know.


true assuming that technological advancement is infinite and continues to double every decade (which might not be the case)


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## Parson (May 19, 2009)

ManTimeForgot said:


> Sceptical:
> Alien technology of 500 years advanced is (given the median estimate of two-fold increase in technological ability every 10 years) a 1,125,899,906,842,624 (that's 1 quadrillion for ease of reading) fold increase in technological ability.  A difference of that magnitude is completely incomprehensible to us.  Anyone who seriously thinks that ET's technology is going to be anything other than magic to us is so arrogant and human-centric as to be living in a state of complete ignorance.



Given our longer history, not just the last century, the rate of increase might be so much less that in 500 years the tech will be only 2 or 3 times better. I remember reading of an Egyptian boat that could not be very accurately dated because the design of Egyptian boats did not change for 1000 years!

Sorry Urlik, I responded before reading to the end of the posts.


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## skeptical (May 20, 2009)

To mantimeforgot

Arthur C. Clarke suggested that : "any sufficiently advanced technology is indistinguishable from magic."

However, that does not give us carte blanche to assume magical powers to an advanced civilisation.   No matter how advanced, they will still be limited.   They will, no doubt, be able to carry out short range teleportation (that is theoretically possible, but beyond current human technology), use nuclear fusion, manufacture anti-matter in appreciable amounts and store it safely,, build cyborg components into their own bodies, use those components to create a kind of 'telepathy' by radio waves, tapping their brains directly into super-internets and many other accomplishments.

However, that does not mean they will be able to wave a hypothetical magic wand and skip lightly across umpteen dimensions, or colonise a planet and leave no material traces.  We are, of course, fully entitled to speculate about advanced alien civilisations, but let us stick to what might be possible, at least in theory, and not assume magic.


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## ManTimeForgot (May 20, 2009)

Gentlemen:

Yes, ET can and will wave magic wands.  It might be some form of string manipulation, but far more likely is that it will utilize some aspect of science here-to-for unrecognized to us.

How much we "really" know about the universe and greater reality isn't really relevant since any number divided by infinity is zero.  Any honest scientist when confronting issues of scope is forced to this conclusion.  That's why Douglas Adams' put forward that a good sense of perspective lead to a "total perspective vortex" (forced to weigh the value of whatever it is that you are or know against all that is results in nothing).   Edward Teller went on record stating that if you take what we don't know about the universe and divide it by what we do know you get a _very_ large number possibly even infinity (perks of having a dad who worked with the man for many years).


It is a valid critique to state that technological progression is not a constant.  But Renaissance is just as likely as Dark Age, and so I was working under the assumption (over a totality of history) that those two things will balance out/counteract.  This is why doubling every 10 years was what I termed a median.  Perhaps technological progress accelerates in the future; quantum computing and planet sized computers (all possible at some point in the future) might very well accelerate the rate of technological progress beyond 2 every 10.  Perhaps dark ages set back a civilization hundreds of years like what happened with China in the 15th and 16th century.

But that isn't really the important thing.  What is important is that our assumptions about what technology will look like for ET are almost undoubtedly all completely wrong.  What we think of a "cyborg" to be is not going to share much if anything in common with what ET would do.  Technology progresses along racial and cultural lines.  So when a race shares almost no common features with humanity and its culture shares nothing in common with our cultures, then there can be almost no presumed form relationship.  Functions will approach similarity as technological capability approaches "maximum" (there are only so many ways to build a water wheel argument).

Every time people have assumed that no further technological or scientific progress would occur they have been astoundingly wrong.  Our imaginations are limited by what we are able to conceive of.  So we are fundamentally unable to deduce what kinds of things ET will be able to do, and to claim that there _must_ be some kind of limit to what ET could do is hubris at best.



Where is ET?  At this very moment some form of ET is closer to the molecules of your body than your clothing; the eleventh dimension (and whatever else is beyond that) is closer to your molecules than anything you "touch" (electro-static repulsion).  Now don't misunderstand me here; I'm not saying that ET is specifically in the eleventh dimension (or any other).  The problem with arguments made in ignorance is that you cannot verify their veracity.  But what you all don't seem to realize is that we haven't the faintest idea what is really out there.  ET might be in the 11th dimension, but then again ET might have decided that the 11th parallel concommitant plane of foldingness was much cooler than the plain old 11th dimension.


Accepting your own ignorance is a bitter pill to swallow, but its one everyone who wants to learn has to swallow sooner or later.

MTF


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## Urlik (May 20, 2009)

ManTimeForgot said:


> How much we "really" know about the universe and greater reality isn't really relevant since any number divided by infinity is zero.


 
true if the Universe is inifinite (which it isn't)



ManTimeForgot said:


> Accepting your own ignorance is a bitter pill to swallow, but its one everyone who wants to learn has to swallow sooner or later.


oh the irony


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## ManTimeForgot (May 20, 2009)

Still not getting it.


The universe is finite.  That doesn't matter.  Reality may or may not be infinite, and is such a huge prospect that even speculating on it is guesswork at best (hubris at worst).


You think that's irony?  What it is is that I am comfortable stating and knowing that I know pretty much jack about the universe and greater reality.  I also fully accept that mankind is cousin to the ant when it comes to our place in the universe and greater reality.  I know we have no clue what's going on.  And while I don't exactly like being ignorant, I accept that this is the case.

Deal with it.

MTF


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## Urlik (May 20, 2009)

and you are also missing the point.

this thread is about ETs that we can class as "Life As We Know It". 
if there are pan dimensional beings (and there could be) then they have always been pan dimensional beings and from our viewpoint they would be omnipresent, so where are they.
they have nothing to fear as far as we are concerned so why are they hiding?
with their quintillion tech they could solve all our problems and help us establish colonies on suitable planets in other systems. they could broker treaties between us and other life forms in our universe and they could enforce those treaties.
so either they don't have any interest in us or they don't, at this time, exist (which means they never existed as they would also be able to manipulate time and therefore would be here now)

and yes I do think it is irony. 
you tell us to accept our ignorance and then you invent gods.


> Reality may or may not be infinite, and is such a huge prospect that even speculating on it is guesswork at best (hubris at worst).


you are the only person in this thread speculating about whether reality is infinite or not.
everyone else is happy to accept that we know we don't know everything, but until better evidence comes along, we'll use the working model that has been put together from several millenia of scientific triumphs and failures and base our assumptions on what we know to be the best possible evidence at this time.

we know that our 3 dimensional universe is finite. what is outside is irrelevent. it is as likely that the outside has no means of initiating interaction with the inside as the inside has of interacting with the outside. so for this argument we can discount it and that includes pan dimensional beings in the 11th parallel concommitant plane of foldingness.

as far as "life as we know it" goes, given that we have a pretty good idea of what conditions are necessery, we can narrow down the areas to look for life and planets that can support it (even if it hasn't evolved past the single cell stage).
given that only 10% of the stars that *could* have suitable planets are older than the Sun we can estimate that there aren't that many ETIs that are more advanced than us and those that are are probably spread out between the arms of the galaxy at roughly the same distance from the galatic hub as we are.
this would make contact rather difficult as the arms of the galaxy are not exactly hospitable and crossing them may be a greater undertaking than crossing the Atlantic on a lilo with no means of navigation.

I agree that, to the primitive, the technologically advanced would appear as gods and that this may have happened in our distant past, but we are no longer the primitives we once were (we now have flying chariots that can unleash destruction upon the unworthy) but just because we have advanced and are continuing to advance doesn't mean that technological advancement is infinite.


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## skeptical (May 20, 2009)

To MTF

I think you may have misunderstood my point.
Sure we are far from understanding everything there is to know about everything.

However, that is no excuse to assume that anything is possible.   It is not.   An advanced civilisation will be able to do things we cannot.  That almost goes without saying.   However, that advanced ET will still not have a magic wand.  It will have to live within the laws of physics.    It is very, very unlikely to drink its soma from a cup made of pure energy.   The cup will be matter, and its function immediately recognisable to one such as ourselves. 

Stone age man made tools out of stone.   We make them out of advanced alloys.   But they are still the same shape (more or less) compared to the old stone tools.   Advanced aliens will still use knives with blades we can immediately recognise as such.

The whole point is, magic aint real.    A fantasy world of advanced technology still does not make magic real.  They will have advanced technology, but it will not be magic.


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## mosaix (May 21, 2009)

skeptical said:


> To MTF
> 
> The whole point is, magic aint real.    A fantasy world of advanced technology still does not make magic real.  They will have advanced technology, but it will not be magic.



Very good skeptical. 

Once society gets beyond the point of believing in magic then it has to accept what it sees is technology.


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## mosaix (May 21, 2009)

Urlik said:


> we don't actually know how much we don't know. if we knew how much, then we'd know what we were missing and have a pretty good idea what most of it was



Donald Rumsfeld anyone?


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## Urlik (May 21, 2009)

mosaix said:


> Donald Rumsfeld anyone?


 
not before breakfast thank you


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## ManTimeForgot (May 21, 2009)

Beyond a certain point there is no need to use knives.  Beyond a certain point there is no need to use a hammer.  You will utilize more energy efficient methods than the use of primitive tools.


You all keep claiming we will recognize ET's tools, but that is complete hubris.  You are obviously thinking ET will always have fingers, hands, legs, or whatever that is going to make it similar to humans.  Our best theorists on exobiology have flat out stated that the chances of ET being even remotely similar looking to humans is astronomically small.


Tools will be different for tentacle based aliens.  Tools will be different for aquatic aliens.  And after a certain point once you start "growing" your tools, fashioning them from paste (nano-scale construction/molecular arrangement), or utilize "self-assembling" structures (materials which "know" what arrangement they should be in and are like superconductors or magnets and strive towards that arrangement) you won't even need "tools" as such.



Just because something is a pan-dimensional being _now_ does NOT mean it always has been.  That is a patently ludicrous argument.  If technology is how something achieved its transcendence out of the universe (transcending reality doesn't make sense, so you won't ever catch me stating that), then at some point it would have had to have been more mundane.  Perhaps there are pan-dimensional beings that always have been (those don't necessarily have to be all that advanced just thought I would point that out) as in they are native to that state, but exactly HOW would we notice such a thing?  I suppose you are claiming our supremely in depth knowledge of quantum reality would allow us to detect such a thing?


Urlik, you are making some pretty hefty assumptions about ET's psychology and general nature that just doesn't have any reasonable justification.  What does ET have to fear from us?  The oppositional question is why would ET care at all?  Do you notice every ant that you come across or step on?  And when you do notice an ant do you give the ant anything more than a passing thought?  I'm guessing you are the kind of person to stop at every ant hill and try and fix all their problems?  Why doesn't ET manifest and "solve all our problems?"  How about: "What happens if that leads to greater disaster in the future if we aren't allowed to figure out how to solve such problems for our selves?"  Perhaps something akin to the "Prime Directive" from Star Trek keeps advanced aliens from interferring with lesser species.  Perhaps they don't care.  Perhaps they are prevented from interferring by something greater than themselves.  Perhaps it isn't worth the investment coming here for a galactic conqueror.  Perhaps we don't _have the first clue about it and speculating about it is about as likely to be correct as speculation on the surface temperature of a planet we haven't even discovered yet._


I'm not "inventing" anything.  You take billions of galaxies and you get some race to have survived its intellectual onset a billion years before us (somewhere some species managed this, statistically speaking).  That billion year science/tech advantage amounts to something truly monstrous.  They almost certainly created their own private universe some time ago.  Perhaps they are still here; observing, collecting stuff (whatever it is that ET's collect), researching, who knows really?

And just how exactly are we going to notice these giants of the cosmos?  Our technology probably doesn't even interact with the level of reality that these aliens use?  Perhaps there is some "apparently random" fluctuation in light beams or electron pathing that isn't actually random that _could_ be used to detect such a thing (pure utter garbage level speculation), but when was the last time you heard about a single scientist (let alone the whole community) spending every waking moment studying a particle stream looking for anomolies caused by alien interaction (it really is as absurd as it sounds)?   Perhaps it has been thousands or millions of years since ET entered into our sector of space.  The tools/artifacts left behind might not even be in our 3 dimensional space or might have been completely organic and designed to break down/self-disassemble after a certain period of time.  The Fermi Paradox is the same level of stupid hubris as the "Time Traveler Paradox."  An infiltration expert from the 25th century using brain alteration, advanced cultural uptake techniques, more advanced espionage/data gathering techniques, etc is going to get noticed by us how exactly?  Perhaps Time Travelers are only allowed to travel _if_ they could not get noticed in the first place?  The same thing might hold for aliens by galactic accord.  You can only go some place if you wouldn't be noticed.  Who knows?


I'm not suggesting I know for sure (I admit I am fairly confident, 90% confidence) that Super ET is out there (or time travelers for that matter).  What I am trying to get you all to realize is that the assumption that we _should know if ET is out there_ is *monumental hubris*.  We aren't in a position of knowledge.  We are in a position of ignorance.  Exactly what are we going to compare to or contrast against in order to determine where, when, or what ET is?  How do you know ET is going to interact with light or gravity anymore?  You don't.  How would you find ET's *old* tools?  We haven't explored a percentage of space expressable as a fraction yet (technically it could be, but the fraction's denominator would take up more space than I have to post in).  Needle in a haystack doesn't even come close.  How do we even know what form the *old* tools will take?  We don't because we don't have any clue what they will look like.  What sort of tools would swarm aliens need/use and what form would they take?  We don't have any idea because our planet's Bees haven't magically started building hammers!


The best we can do is try and be impartial observers and collectors of fact.  Trying to make statements about something as large as our galaxy (let alone whole universe) while possessing knowledge as limited as our own (we have next to ZERO knowledge about light years worth of space in our galaxy let alone the billions of other galaxies themselves) is hubris of a level that words simply fail to describe the degree.  If we someday hit the galactic lotto, then so be it.  But I won't be holding my breath waiting for it.

MTF


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## Urlik (May 22, 2009)

we don't even know if there are any other dimensions. even the best of the superstring theories only predicts them.

the predicted extra dimensions may not be connected to each other in the same way our 3 spatial dimensions are. each one could exist in isolation to the others.
we might find the hypothesised ETs less significant than ants as they are limited to a single dimention while we have 3 to work within.

or the extra dimensions could be branes, but if that is the case there is also no movement between them (if there was, then we would be able to interact with the zero, 1 and 2 dimension branes in the same way that you suggest "higher" dimensional beings can with ours.

either way, other intelligences within these dimensions, whether they exist or not, can effectively be dismissed.

the only ETs in our galaxy that are worth considering as possible are those that inhabit our 3(+1) dimensions and are "life as we know it" that has the basic drive to reproduce itself.
if it doesn't have this basic drive it can't evolve into a self aware intelligent being and we might as well stay here and try to communicate with bacteria


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## skeptical (May 22, 2009)

The term 'other dimensions' is a bit misleading, anyway.   A dimension is only a direction.   It would be more correct and more meaningful to talk of other universes.  According to string theory, there may be E500 universes other than our own.   Most would be utterly alien, and instantly lethal to any inter-universal traveller.   However, the number that ET could survive in would still be a very large number.

However, even if advanced aliens have learned to travel between universes, and have set up home in another universe - or another quintillion universes - they still have to deal with the same laws of physics when they visit this universe.   Magic still don't work!

This means that tools, no matter how esoteric, still deal with the real world, and will conform to universal properties.   A lever is still a lever, even if wielded by an alien squid.

One problem I have with the idea that ET is simply too altruistic to interfere with our world, is that ET probably visited long before advanced life existed on our world.   Sure, according to the 'Prime Directive', ET might be prohibited from interfering with humanity - but ET (of one species or another) should have been around way back 1 billion years ago.   When the Earth was populated by no more than oxygen generating slime, why did ET not colonise?   Clearly, there was no ethical dilemma at that stage.

I still see the only viable answer as being that ET's are rare.


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## Urlik (May 22, 2009)

skeptical said:


> I still see the only viable answer as being that ET's are rare.


 
either that or there are other obstacles to overcome.
when you look at the cost for us just to get into orbit, even a slight increase in the mass of the Earth would have a huge impact on the the cost to do this.
then to leave the solar system you have to break free of the Sun's gravitational field.
it could be that their home planet has too high an escape velocity for them to even consider travel within their system let alone emabark on an interstellar journey, or as in our history, some pioneering work was done but the cost became prohibitive in the long term.
if their sun is more massive than ours then they may be able to travel within their system but the cost is too high to leave it.

it could be that, like us, they haven't figured out a good method for dealing with cosmic rays outside a low planetary orbit.

the chances are that there is life as we know it out there, but there are too many obstacles in the way to make contact between intelligent life forms impossible on a practical level.


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## skeptical (May 23, 2009)

To Urlik

The obstacles you are proposing are indeed real problems to humanity in today's world.   However, if we consider them against a time factor of thousands of years, and the technological progress that should occur over that time, they will cease to be problems.

The much discussed space elevator is a theoretical possibility.  It requires some technical development (mainly making lots of very long cheap buckytubes), and one hell of a lot of economic investment.  However, both should be possible in the next 100 years.  Once it is in place, leaving the Earth's gravity will be relatively easy.

Cosmic radiation is also a major problem today.   However, there are numerous organisms that can handle that radiation and much more with ease.  These are organisms that have DNA repair mechanisms that are much more effective than ours.   In theory, we can carry out a minor genetic modification on humans, giving ourselves the ability to repair DNA rapidly, and tolerate all the cosmic rays in space no problem, and to become more resistant to cancer as a side benefit.  Simple inheritance will ensure that the whole of _Homo sapiens_ retains this ability, for ever after.

You suggest ET may have too big a gravity field to escape, or a sun too big.   That is true.   In fact, there are numerous reasons why a single species may never colonise other star systems.  However, if there are *many* species of ET, those restrictions will not apply to all of them.   Remember that the time scale we are talking about covers the last 2 to 3 billion years.   If the ET optimists are correct, there must have been numerous intelligent species over that time period, and* some* of them must not have been restricted in these ways.

Which is why I believe that ET's are very rare.


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## Urlik (May 23, 2009)

skeptical said:


> Which is why I believe that ET's are very rare.


 
I'll agree that ETs that manage to leave their system and explore the galaxy are rare for one reason or another, but I also expect that there are many more in various stages of development that never have or will leave their systems


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## ManTimeForgot (May 23, 2009)

Why didn't ET colonize is an excellent question (sure it poses no moral dilemma), but it begs all sorts of questions that we can't possibly know the answers to.

It presumes ET's goals include expansion/colonization.
It presumes ET is interested in planets (ET might be beyond caring about mere planets).
It presumes the solar system and earth have the right type of gravity and size to be considered by ET (perhaps ET likes Gas Giants larger than Jupiter).
It presumes Earth has resources/atmosphere of the type ET is interested in.
It presumes oxygen based life is what ET is interested in cohabitating with.

And I am sure there are other questions that an ET or scientist would come up with that I have just failed to consider.


Dimensions are more complicated than mere direction, but less complicated than alternate universes (though alternate universes is a valid construct to involve).  Dimensions as we are talking about is more like a plane of existence.  It is a "different level" of reality.  The 5th dimension and above are "spacetime overlap."  What this means is precisely bupkiss to us "normal" beings.  But to a being with multispatial perception or some other sensory faculties way beyond ours it may not.

And it would be hubris on our part (yet again) to assume that all the dimensions or planes or universes we know about or theorize is all there is to reality.  The universe of discourse (all that is; reality) for our purposes of discussion has become so large as to be logically indeterminate (we can know nothing about what we talk about, and so all assumptions become equally true and false).


Perhaps you all are correct and ET is rare.  Perhaps ET never wants to leave his solar system.  Perhaps similar habitable planets to your own is hard to find.  Perhaps most cultures completely self-destruct, die by cosmic accident, or clash in inter-solar warfare before they can achieve high-level expansion.

Or perhaps just as likely (I say this because statistically we have no idea how rare anything is since we know nothing about the subject) ET doesn't interact with us for one or all of the various reasons I have postulated before.



The point I am trying to make is that speculating about the indeterminate is foolishness at best.  We know nothing about what we speak and so coming to any conclusions is logically incorrect.

MTF


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## Urlik (May 24, 2009)

ManTimeForgot said:


> The point I am trying to make is that speculating about the indeterminate is foolishness at best. We know nothing about what we speak and so coming to any conclusions is logically incorrect.
> 
> MTF


 
we know roughly what conditions were required for life to start on Earth but we don't need to know exactly what they are for them to work (as they worked just fine without our help in the first place)
there is a statistical probability that those conditions have been met elsewhere in the Galaxy (even with a probability of 99 in a hundred for, there is still the chance that the single role of the dice comes up as the 1 time in a hundred against)
these 2 factors let us hypothesise that there is a probability that somewhere out there an intelligent life form evolved (although they may have evolved from their equivalent of the reptile instead of their mammal or even insect or they may still live in the oceans and never need to develope tools)

it isn't hubris to think this because we know it can happen as it already has and we are the proof.
it isn't hubris to think that life as we know it would have similar goals to us. all life as we know it has the same basic goal from the humble amaoba right up to us and that is reproduction. this leads to expansion until limited by resources. if they have developed a technology that allows them to increase their resources then they will if they want to be able to continue reproducing and planets happen to be a pretty good source of all the resources for life as we know it to continue to reporduce
it isn't hubris to think that the Earth is the type of planet they'd be looking for as in our initial hypothesis we were working with life that has evolved on a planet similar to Earth and would find the Earth a pretty attractive prospect. life in gas giants, if it is even possible, wouldn't be life as we know it because it would have had to originate from a completely different set of circumstances to those on Earth nearly 4 billion years ago and would have followed a very different evolutionary route. 

if we limit the possibilities to what we know are possible, the statistical probabality that there is another intelligent life form out there that followed a similar route to us is worth considering


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## skeptical (May 24, 2009)

I tend to agree with most of what Urlik just posted.   Life is likely to have formed elsewhere in our galaxy.   I have never had a problem with that idea.   My problem is the concept that intelligent and civilised life is common.   I do not believe that.  I think that it must be rare, for reasons I have already mentioned.

MTF lists a number of reasons that ET might not have come our way on a colonising mission.   Sure, for any single species of ET, such a reason might be valid.   However, no such reason will be valid for a large number of ET species.  Maybe ET is not, for example, interested in expansion.   Sure.   And out of 100 different species of ET, perhaps 10 to 20 fit that category.   

However, one of the characteristics of life is the drive to disperse.  Evolution creates mechanisms for effective dispersal.   Seeds and pollen blow in the wind.   Coral and barnacles make larvae that drift on ocean currents before settling far from home.   Birds and insects fly.  Fish swim.  Land animals run.

It is utterly realistic to conclude that alien life must also have some kind of dispersal mechanism, to survive and evolve.  Intelligent life is likely to have such a mechanism built into its behaviour.  For example :  human curiosity and restlessness.

For this reason, I think most ET species will, eventually, travel between the stars, and establish colonies elsewhere.   Some would be aggressively expansionist. 

If intelligent civilised life is common, some will also be oxygen breathers and *extremely* interested in Earth as it was any time over the last eon.


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## Parson (May 25, 2009)

And so *Skeptical *has brought us full circle. Where are they anyway?


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## mosaix (May 26, 2009)

Urlik said:


> if we limit the possibilities to what we know are possible, the statistical probabality that there is another intelligent life form out there that followed a similar route to us is worth considering



This is sensible. We know it's happened once. We know (approximately) the conditions under which it happened. Because of the number of stars that exist we know that there is a good chance that that the same conditions have existed many times before and may again.


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