35 replies to this topic

[Richard Leis]

Milan M. Cirkovic and Robert J. Bradbury argue in "Galactic Gradients, Postbiological Evolution and the Apparent Failure of SETI" that current SETI research ignores postbiological evolution. The authors present an interesting solution to Fermi's Paradox: biological lifeforms evolve in the Galactic Habitable Zone but "will tend to migrate outward through the Galaxy as their capacities of information-processing increase, for both thermodynamical and astrochemical reasons."

Astrobiology research may provide an important foundation for Technological Singularity studies. If there are biological lifeforms and postbiological lifeforms out there, perhaps we can get some insight into our own future. Interestingly enough, last week the Arizona Board of Regents approved a new astrobiology center to be created at the University of Arizona (where I am currently an undergraduate majoring in geosciences.)

[bgwowk]

Shades of Vernor Vinge's Transcend! (from Fire Upon the Deep). Doesn't explain the Fermi paradox, though. All it takes is one Keith Henson seeding his way to the Far Edge Party to leave all habitable planets in the galaxy littered with the life forms of the Star Wars Cantina.

I first wrote about this privately in emails in the 1980s, but I'll say it here for the public record: As life from Earth spreads throughout the galaxy, habitable planets will eventually become colonized with evolving life forms and civilizations with the same prevalence and diversity seen in science fiction. This will happen so quickly on a cosmic timescale that it will soon become superficially difficult to distinguish native life forms from life forms with Terran ancestry, especially when nanotechnology could theoretically be used to deliberately create fake alien civilizations. (Microbial contamination left by explorers within the solar system will be an early version of this.) Find your aliens soon, or you may never know whether they are really aliens or fellow Terrans.

If Cirkovic's and Bradbury's paper is right about computing-optimized beings prefering to reside outside the galaxy, this makes it even more likely that warm terrestrial planets will be left to classic biological life forms, including human-level intelligences (shades of Vernor Vinge again). Therefore, in addition to the hyperbeings living in the extragalactic cold, there should still be plenty of less evolved intelligences communicating, travelling, and engineering within the galaxy. But we don't see them. The Fermi paradox remains.

---Brian Wowk

[1arcturus]

Perhaps the evolution to "hyperbeings" also happens "quickly on a cosmic timescale," as it is expected to for humans on Earth (backtracking again to Vinge's Singularity idea). Automation left by ascended beings on their homeworlds might continually transform any newly evolving higher life forms, so that no noticeable "animal life" might be observable on any planet.

The notion of Singularity works against the Fermi paradox in general. It might be a fallacy to believe that humans could notice "hyperbeings" even if they "saw" them, any more than ants recognize the humans whose feet they dodge. And of course it may be irrelevant to such beings to contact human beings, even if they could "stoop" to communicate -- they might see humans as obvious, predictable, very-well-understandable instantiations of general knowledge, so that they don't bother to investigate us or molest us. The same way most of us don't stop and gawk at pigeons, or run up to see how one individual pigeon's feathers might be marked!
To us, our civilizations are diverse and we think we would be fascinated by discovering other, similar civilizations. But we are one eye-blink on the continuum of evolution, seeing things through our characteristic eyes.

[bgwowk]

Perhaps the evolution to "hyperbeings" also happens "quickly on a cosmic timescale," as it is expected to for humans on Earth (backtracking again to Vinge's Singularity idea). Automation left by ascended beings on their homeworlds might continually transform any newly evolving higher life forms, so that no noticeable "animal life" might be observable on any planet.

That's a bit like SETI people who say they expect radio waves, but not physical visits, because really advanced civilizations would forcibly prevent interstellar travel by anyone. That doesn't seem likely or practical. On a cosmic timescale, any lightspeed communication is bound to have physical replicators not far behind.

The important point about pigeons is that we tolerate them. And not only pigeons, but the myriad of other natural replicators that have relatively brainlessly spread through the whole biosphere. To believe that an intelligent species could advance to "transcendence," and not leave a plethora of other less advanced life forms spreading throughout the galaxy behind them presupposes a rapid and draconian holocaust of all spacefaring life once trascendence is achieved. It would be like humans suddenly and unanimously deciding to kill all flying animals with complete effectiveness because they wanted the sky to themselves. That would be really hard to do, even assuming there was motivation to do it.

Spacefacing replicators with a proclivity to spread through galaxies like plants and animals in planetary biospheres seem to be an inevitable result of civilizations only slightly more advanced than we are now. We don't see such replicators. The Fermi paradox remains.

---BrianW

[Richard Leis]

My response would be more in the lines of 1arcturus' thinking. While replicators may litter the galaxy with less advanced life forms, perhaps an explanation for Fermi's Paradox lies in the huge difference between the transcendent species and the less advanced species.

I have nothing to back up the following percentages and I am using them for illustrative purposes only: perhaps less advanced species (the vast majority without current human-level intelligence) make up 90 percent of all replicators while transcendent intelligences make up only 10 percent of all replicators. This dichotomy would occur because transcendence happens so quickly yet so rarely. In other words, the universe is teeming with lifeforms, but we are not advanced enough to detect the majority and the minority are so advanced that we wouldn't recognize them as such even if they were standing right in front of us. This precludes the "Rare Earth" hypothesis and supports a "Rare Communication" hypothesis instead.

Take our own planet and history of life as an example. For 3.5 billion years (maybe a little longer) there have been lifeforms but no sufficiently advanced intelligences. In a blink of an eye and only recently in geological history has such an intelligence emerged - [I]homo sapiens sapiens[U]. In even less time we will transcend into posthumans. That means that if an alien wanted to communicate with humans at our current level of advancement, they would have a very short window to do so. If all civilizations follow a similar trajectory, then it is no wonder that we haven't detected any. The galaxy could be teeming with intelligent civilizations but none of us have reached the ability to detect the others within that narrow window of time. We don't see them until after we transcend. And then they cannot see us at all.

[bgwowk]

I think people are too hung up on communication. Absence of signal is not the problem. Absence of PHYSICAL PRESENCE, right here, right now, is the essence of the Fermi Paradox. It's not absence of transcendent beings. It's absence of at least incidental spacefaring replicators that should have evolved in parallel.

In other words, the universe is teeming with lifeforms, but we are not advanced enough to detect the majority and the minority are so advanced that we wouldn't recognize them as such even if they were standing right in front of us.

You don't need to be advanced to detect the majority less intelligent replicators. We should be tripping over them like weeds. Instead, all complex life forms on Earth seem to fit nicely on a phylogenetic tree suggesting common ancestry in very simple life forms, and none of them are spacefaring (except for microbes). This suggests that all life on Earth is native, with microbes as the only possible exception. In other words, we are alone.

Of course this is completely consistent with the Anthropic Principle. If there is a plurality of universes, only a minority of which are properly tuned to produce life, there will be many more universes in which life barely manages to arise once, and then spreads, than universes in which life independently evolves in many different locations. By analogy, it's generally believed that life on Earth arose as a localized fortuitous event, and then evolved and spread, rather arising independently at many different locations on the planet.

---BrianW

Edited by bgwowk, 23 June 2005 - 04:18 AM.

[Richard Leis]

Fermi sited the lack of both technologically advanced civilizations' physical artifacts and their transmissions. Based on our own civilization's history, transmissions propagate through the galaxy long before physical artifacts do. To get around this natural progression, the advent of faster-than-light (FTL) technology would be necessary so that physical artifacts could overtake earlier transmissions.

If we stick with your incidental replicators, however, the solution presented by Cirkovic and Bradbury suggests that those incidental replicators would not be where we are currently looking for them. If the transcendent beings are trending toward the outskirts of the galaxy, then any incidental replicators would trend toward that direction as well, like a trail a bread crumbs leading back to the home of the transcendent beings.

You don't need to be advanced to detect the majority less intelligent replicators. We should be tripping over them like weeds.

But you do need to be advanced. Your detection horizon is dependent on your technological level. Close to your planet you are limited by the sophistication of your in situ technology. Further from your planet you are limited by the sophistication of your remote sensing technology. As you progress, your in situ and remote sensing horizons push outward. Perhaps when you create FTL technology your in situ technology horizon finally catches up with your remote sensing horizon. By then, however, you are likely a transcendent being and less likely to be detected by the locals. To the locals, it is as if there is no one out there.

If I understand you correctly, however, you are suggesting that all that technology isn't necessary because the alien artifacts or incidental replicators should already be in our solar system, well within the capability of our technology to detect. Then where are they? A few possibilities:

1. It is more likely they are elsewhere rather than here, statistically. The Transcendent Galactic Habitable Zone has a much larger volume than the Galactic Habitable Zone.
2. Even these incidental replicators are sufficiently advanced to be undetectable in our own backyard.
3. Physical evidence and incidental replicators are no longer macroscopic by the time a civilization sweeps through your own system. (Efficiency increases and size shrinks.)
4. They live in the Oort Cloud and never bothered to move into the inner solar system.
5. They hate solid ground beneath their feet. (They live in the oceans of Europa, the atmospheres of the outer planets, etc.)

[bgwowk]

Based on our own civilization's history, transmissions propagate through the galaxy long before physical artifacts do.

We have different standards of "long." Earth's first radio transmissions will reach the far side of the galaxy at best a few millenia before the first physical artifacts do.

I think you are still missing the basic paradigm I'm discussing, which is along the lines of Dyson's "greening of the galaxy." The essence of life (replicators) is variation and selection. Variation and selection guarantees that life will eventually expand to fill all ecological niches available to it. That is why the entire surface of the Earth, from the upper atmosphere to the Marianas Trench, is saturated with a biosphere of living organisms of incredible diversity. That is the destiny of the galaxy once sophisticated, evolving replicators become spacefaring. Life will not stay confined to Oort coulds or other far flung locales. It will be EVERYWHERE in unimaginable diversity.

Wait and see.

---BrianW

[1arcturus]

That's a bit like SETI people who say they expect radio waves, but not physical visits, because really advanced civilizations would forcibly prevent interstellar travel by anyone.  That doesn't seem likely or practical.  On a cosmic timescale, any lightspeed communication is bound to have physical replicators not far behind.

My point was that there might not be "physical replicators" of the sort we might distinguish as such.

Humans have already floated the idea of "uplifting" animals. Perhaps all advanced civilizations would consider it an ethical obligation to uplift not only all existing significantly-advanced lifeforms on their planet, but also all new ones as they evolve to a certain point.

This would not be like exteriminating them, it would be like blessing them. There would be no holocaust, all ascending lifeforms would take on a certain compatible form, which would not be - from our vantage point - "animal like" or humanlike or perhaps even lifelike.

No less advanced life forms would spread out from such planets because all life forms leaving the planet would already be in transcended form.

Humans have gotten to the moon without too much injury, but I doubt we will ever settle, say, on Mars, in our present form.

So the only radio signals we would get, in this scenario, would be from civilizations that just happened to be at the EXACT same split-second moment in their historical development (just before ascending), and close enough to us to be able to be detected, and in the precise line of sight of our detection devices at the exact right moment. THIS would be exceedingly unlikely.

But it may have already happened. The scientist who recorded the "WOW" signal now believes that it was, indeed, an artificial signal of extraterrestrial origin. There have been no sustained efforts to revisit the area (just very brief tests).

[Richard Leis]

I think you are still missing the basic paradigm I'm discussing, which is along the lines of Dyson's "greening of the galaxy."

I'll admit, I'm on a steep learning curve It's helpful there will be an Astrobiology Center here at the University of Arizona soon.

So, if this "greening of the galaxy" seems likely, why hasn't it happened? Are we the first? I still think it has something to do with the distances and the willingness of any civilization to do what we assume they will do. My guess is that the galaxy is full of life - it is already green, but each planet is an island (with perhaps a small contribution from panspermia within a system). A small fraction of these islands create a lifeform capable of intelligence and interstellar travel and communication. By the time these civilizations become capable of leaving behind other physical replicators, however, their priorities have changed and they simply do not. No cross greening because each civilization is otherwise preoccupied.

[bgwowk]

1arcturus wrote:

Humans have already floated the idea of "uplifting" animals. Perhaps all advanced civilizations would consider it an ethical obligation to uplift not only all existing significantly-advanced lifeforms on their planet, but also all new ones as they evolve to a certain point.

This would not be like exteriminating them, it would be like blessing them. There would be no holocaust, all ascending lifeforms would take on a certain compatible form, which would not be - from our vantage point - "animal like" or humanlike or perhaps even lifelike.

Indeed. That kind of totalitarian biological fascism and enforced conformity is the only way there could be other intelligent spacefaring life in the visible universe. But even that scenario has a built-it contradiction: Why has not Earth already been "blessed" in this manner?

enoosphere wrote:

So, if this "greening of the galaxy" seems likely, why hasn't it happened?

That is the Fermi Paradox.

Are we the first?

That is the most likely resolution of the Fermi Paradox.

The single most influential factor in my thinking on this subject was coming to an understanding of nanotechnology in the mid-1980s. With mature molecular nanotech, all it takes is one walnut-sized probe to terraform an entire planet, sending a thousand other probes just like it at near the speed of light to nearby star systems. All it takes is one company, or someday even one nanotech hacker, to get the idea of building such a probe, and the galaxy will be unmistakably changed. That's what I mean about totalitarian control of all intelligence being the only way to prevent such scenarios. And soon.

---BrianW

Edited by bgwowk, 24 June 2005 - 07:54 PM.

[1arcturus]

Indeed.  That kind of totalitarian biological fascism and enforced conformity is the only way there could be other intelligent spacefaring life in the visible universe.  But even that scenario has a built-it contradiction: Why has not Earth already been "blessed" in this manner?

I am a supporter of at least one form of uplifting. "Totalitarian biological fascism" sounds like name-calling. Totalitarian - only if conducted by a totalitarian government. Fascism - only if conducted by fascists. Biological - yes.
We would need to verify that animals already wanted things in the direction of uplifting, and then uplift them step by step. It would not result in homogeneity - on our planet, intelligent cetaceans, chimpanzees, elephants, etc. (since they are following close behind us) would surely liven the diversity. Ascension would only affect their capabilities and the formats available to them. Dolphins can't fly to other planets (unlike the funny THANKS FOR ALL THE FISH scene) as they are; if they wanted to, and had the power, they might choose a form different than a posthuman would choose for interstellar travel, but we can be sure the form wouldn't be a dolphin (or a human). Postdolphin, I guess you could say, but probably mingling with a vast explosion of posthuman clades.

Earth might not have been uplifted because aliens are only uplifting their own planets, out of a sense of common obligation. Besides, they might notice we are about to uplift ourselves - no sense in pushing a car after its engine starts.

The single most influential factor in my thinking on this subject was coming to an understanding of nanotechnology in the mid-1980s.  With mature molecular nanotech, all it takes is one walnut-sized probe to terraform an entire planet, sending a thousand other probes just like it at near the speed of light to nearby star systems.  All it takes is one company, or someday even one nanotech hacker, to get the idea of building such a probe, and the galaxy will be unmistakably changed.  That's what I mean about totalitarian control of all intelligence being the only way to prevent such scenarios.  And soon.
---BrianW

I am trying to understand why you think an alien civilization would want to send out probes to terraform (or alien-a-form) other planets. Sufficiently advanced interstellar travelers would surely not NEED terraformed planets, since they could live anywhere in space or on planets as-they-are (or inside suns or behind black holes, etc.). Besides, "greening" every other planet just because yours was green, well, there is some kind of homogeneity. But I won't call it totalitarian or fascist Instead of colonizing, or polluting, alien planets, it could be that ascended aliens have other interests, related to their new natures, incomprehensible to us. 'Reproduce, spread, and multiply' is a longstanding evolutionary agendum on Earth, but it might give way after sentient beings come into control of their own evolution. 'Reproduce' is already starting to fall among humans, and we haven't even got indefinite lifespans yet. 'Multiply' might become superfluous after we become able to run simulations of huge numbers of permutations of life & intelligence possibilities - when you can play all variations of a theme on your own violin, you don't need any other composer. It would be reinventing the wheel, so to speak. Just a thought....

I don't care which way it turns out - there would be pluses and minuses of being the first, and also of not being the first. It will be a wild ride either way

[bgwowk]

"Totalitarian biological fascism" sounds like name-calling.

It is name-calling. I find the idea that desires to reproduce are primitive impulses that need to be forcibly engineered away offensive.

I am trying to understand why you think an alien civilization would want to send out probes to terraform (or alien-a-form) other planets.

It doesn't take a whole civilization to do it. As resources per-entity increase, it takes an ever smaller number of entities to do it. Ultimately even just one entity (e.g. me, or what others like me will one day become) could do it.

Don't you see that this is a recurrent theme throughout history? Explorers and frontiersmen are always a minority. (Non-conformists are a minority by definition.) But this is the minority that always manages to escape and reproduce anew elsewhere, giving rise to a new conformist vs. non-conformist rift, and then another wave of migration, ad infinitum.

Carl Sagan, a big SETI advocate, was always confronted with this dilemma of why if ETs existed they were not physically present. He always explained it as you do, with beliefs that *really* intelligent life would have supressed desires to reproduce and travel. He thought it should be obvious. His arch nemesis, of sorts, was Timothy Leary-- a big space migration advocate of the 1970s. There is a story of Carl Sagan visiting Leary in prison after a drug bust. The prison was in lock-down after a riot, and Leary was sitting in his cell literally in chains. Sagan asks Leary, "Tim, tell me again why you want to leave this planet?"

So, 1arcturus, if you want to know why an alien civilization would inevitably send out probes to terraform other planets, build Dyson spheres, move stars, and ultimately alter the physical form of whole galaxies, I will tell you why. The answer is the same as how America was built. These things will be done by persecuted minorities escaping narrow-minded home worlds that believe their dreams and aspirations are primitive impulses to be engineered away.

1arcturus asks BrianW, just before BrianW's lobotomy, "Brian, tell me again why you want to leave this planet?"

---BrianW

[Chip]

I think maybe a compromising perspective might be closer to the truth. First of all, I understand that Heinlein restated the Fermi paradox as "Can intelligent life survive its own information explosion?" I think some can and do but they are few. Secondly, if intelligent life does survive its information explosion I believe they will have many many options, life on planets may seem rather arcane and terraforming unnecessary and unwanted. Life in many large specially constructed colonies might be so nice and hospitable that the effort to terraform will be virtually nil. I think it was Stewart Brand or at least some one he interviewed who once asked "Would intelligent life want to live on planets?"

I see the work of Gerard O'Neil and I see a tremendous possiblity for humanity to move off planet fast. Carbon nanotube fibers will soon, within a couple of decades allow us to build elevators to near orbit. The Lagrange points offer us a great place to build automated factories that could churn out Bernal spheres. O'Neil cylinders and toroids fast to be deployed throughout the solar system, time and space and resources enough for a very large population.

I see the struggle for a P2P paradigm of civilization to realize itself. Seems it would embrace quiet efficent communication technology, perhaps narrowly focused but many laser and similar focused and high capacity means rather than unfocused low content radio communications such as what SETI is designed to study.

So, the reason why we haven't detected them might be that those who leak off radio communications such as we do presently (actually less so as we seemingly tend towards more focused higher broadband communcations) quickly evolve to either destroy ourselves and/or move to more efficient communication systems that leave us and others pretty much out of the loop.

Seems to me the roving replicators might be something that happens sometimes but probably rarely. Once the information explosion is tamed to giving us sustainable options, the options will be many. We will be able to use what is available to us so efficiently we wont need to spread and our communications will become ever more directed and difficult to eavesdrop upon.

I am biased. I would like to live a very very very long time. If that were to be the case, I'd like there to be a resolution to the Fermi paradox that would suggest long long life were possible. In the long run I don't know what will happen but since I would like to live long I will seek to see if there is a way to tame the information explosion so our growing powers do not lead to calamity but rather, an open ended scenario. In that respect I believe it is possible that there is much life in universe that survives its own information explosion and that I and others of this life font can find the ways and means. For ourselves, appears there is no one who will be more motivated to resolve the Fermi paradox in favor of our own successful outcome than ourselves. Time to seek and find some sustainable solutions for ourselves. That would be one way to resolve the Fermi paradox, by choice.

[bgwowk]

Chip wrote:

Seems to me the roving replicators might be something that happens sometimes but probably rarely.

That's all it takes. Just one mutant with a migration and replication meme, and that mutant becomes the dominant life form in any region of space where life doesn't already exist to protect its turf. Static non-migrating civilizations are instrinsically unstable, like trying to balance a broomstick on a fingertip.

20 years ago, a collection of essays analyzing this question was published as a book entitled, "Interstellar Migration and the Human Experience." As I recall, even the most pessimistic analysis in the book, assuming leisurely chemical rocket jaunts of ordinary humans from Oort cloud to Oort cloud concluded that colonization of the whole galaxy was unavoidable within 100 million years (before the sun even finishes one more orbit around the galactic core).

Whether planetary surfaces or smaller colonies are the preferred mode of residence is irrelevant to the Fermi Paradox: If small colonies are preferred, then the trend will be to disassemble entire planets rich in heavy elements to build them. Instead of, "Why aren't all planets terraformed and lush with life?" the Fermi Paradox becomes "Why are there any small planets left at all?"

Like Chip, I hope the resolution to the Fermi Paradox is not that intelligences self-destruct before they diversify and space migrate. I hope the resolution is the most likely alternative: That the universe really is the untamed wilderness it appears to be.

---BrianW

[Chip]

Brian: the Fermi Paradox becomes "Why are there any small planets left at all?"

Our solar system appears to provide a great deal of material for space colony construction without having to dismantle planets. How many planets has humanity discovered outside of our solar system? I think it is only a handful, so far. Now we have to monitor them to see if they dissapear to resolve the Fermi paradox in the, perhaps, unlikely situation that other life would need them rather than having sufficient natural satellites or asteroid material for their own continuance and expansion? Maybe that would bear fruit in a hundred years or so. Still wouldn't resolve the Fermi paradox if we never discoverd such. I'm not going to wait. I'll still function to resolve the Fermi paradox in our favor in the here and now. When it comes right down to the crux, I really don't care if they appear to not have made it out there. The path exists for us to make it or blow it here.

[bgwowk]

Millennia ago, people could not imagine why anyone would need more wood than could be found in the bush surrounding their village. By the mid 20th century, people could not imagine why anyone would need more wood than could be obtained deforesting the entire planet to the limits of its ecological tolerance. By the late 20th century, people could not imagine why anyone would ever want more building material than could be obtained by disassembling all the moons and asteriods in a solar system. Is there not a trend here?

Why disassemble entire planets? There is the obvious reason that if a million O'Neil colonies are good, then a trillion must be better. But there are other reasons too. For starters, you need to disassemble planets to build the hardware necessary disassemble stars. Any beings serious about living a long time (immortality), cannot allow the energy resources of the galaxy to be uselessly squandered away into intergalactic space over just a few billion years. Better management of the energy resources (fusionable elements) of the galaxy could permit life to continue for trillions of years.

What it comes down to is that the universe, or at least our galaxy, currently appears to be in a grossly natural state. Theoretical means and motives for tampering with this state are so plentiful that it's almost impossible to imagine intelligent life existing in a galaxy for any great length of time without tampering with it. We see neither such tampering nor any complex replicators of non-local origin. Hence there is the likelihood that we are alone in the galaxy.

---BrianW

[Chip]

Looking around I guess I see Carl Sagan attributed to the following

Absence of evidence is not evidence of absence.

I also see that this line has been used speciously by Rumsfeld recently so maybe its not that relevant but then, if I just go to the sense of it, seems we live our lives basically striving to preserve at least homeostasis and hopefully find something worthwhile to do to further our options usually adhering to this idea of proceeding from what we know, not what we don't know.

We can speculate about what we don't know. That is what the original article is and its interesting. There is a basic problem with the article as with many, it is not easy to get a quickly quotable passage from the text. The PDF is readily available but it takes two levels of compression to crack to get to source files, apparently. Still haven't got that done yet. Oh well.

I thought of another way that might demonstrate the idea in the original article. I believe it was in an Arthur C. Clarke or maybe Heinlein book that the idea was suggested that a people could travel at an ever increasing speed to approach a sufficient fraction of the speed of light to greatly speed the relative deployment of universe past an eventual collapse of matter back to conditions for another big bang and then these immortals stopped and resettled. Is this plausible? I seem to recall some studies that depicted the distribution of matter in universe as not conducive to an eventual collapse but that was long ago and I bet there has been further analysis of that. I usually think that something that might require an horrendous long time and virtually unimaginable space/distance observations to prove or disprove may via induction always claim that possibly an insufficient amount of time and matter was involved in the analysis finding proof of eventual total cessation. I mean, I find it hard to accept the idea totally without question that universe does not proceed through multiple big bangs, perhaps serially as well as sporadically and with multiple big bangs happening simultaneously sufficiently removed from each other as to be outside of our ability to detect and account for in our models. I don't know but seems like the only feasible plan I've heard of yet and it may be easier than punching holes into just a few degrees dissimilar parallel universe as offered via string theory. There's another thing for which there may be an absence of evidence but I understand some evidence actually does purport to support string theory. I'm not sure if we can trust the evidence that suggests there is not sufficient time or matter to cause another big bang. I ramble.

Maybe it is very easy for those who begin to transcend physical mortality to also transcend dependence on physical manipulation. Maybe there are very easy and readily available methods that do not require terraforming or star engineering for the furtherance of an immortal's desires.

[Chip]

Heck. Not being a phsysics astronomer I could just be farting but, ah, maybe a descending spiral orbit into a black hole would create some extremely fast accelerations as required with the afore mentioned scenario. From the outside we seem to see matter going into a black hole as ripped to shreds and dissapearing from view. Doesn't matter retain it's frame of reference within its consort? Maybe it is us who are getting ripped to shreds and the immortals just traversing doorways to a preferred existence. I really don't know.

[bgwowk]

Chip wrote:

I also see that this line has been used speciously by Rumsfeld recently....

I think it is now time to invoke the Chip modification of Godwin's law, and note that the discussion has probably reached its useful end upon first mention of Republican politics.

---BrianW

P.S. You are right that either travel near the speed of light or travel near the event horizon of a black would tremendously accelerate external time.

[John Schloendorn]

If there were a civilization like ours out there, exactly in the right time-window, within what radius would we have detected it by the SETI or other means?

[Chip]

There is another practical difficulty--that of the life-span of civilizations and the distance between any putative alien neighbors.  If a sentient civilization lasts, say generously, 50,000 years, and needs 10,000 years to get radio transmission, it has a 40,000-year radio transmission life.  This means a single two-way communication can take place with a civilization no farther than 20,000 light-years away. So that bounds the absolute radius of communication.  But the idea of waiting 10,000 years for an answer sent to planets that seem to have oxygen and water around them, does not seem like a very fruitful endeavor.

from http://www.velocitypress.com/seti.php

That source seems pretty contrived and contrite. I read Drake's original exposition of this equation also describing the research he did simulating early earth conditions and finding the creation of amino acids from his synthesis. Seems rather diametrically opposed to the above web site's condemnation. Also, the idea that after using radio transmissions that the civilization would continue to use such for another 40,000 years seems rather assumptive.

The wikipedia on SETI can be found here: http://en.wikipedia.org/wiki/SETI

However, it is important to emphasize that our SETI hunts have been based on assumptions on communications frequencies and technologies that may be laughable to alien societies, if they have the concept of humor. It is possible that intelligent species abandon radio when new technologies are discovered, making the length of time a world is transmitting on conventional radio extremely short. The lack of results do not say that alien civilizations don't exist. They only say that if they do, our most optimistic assumptions for getting in touch with them have proven unrealistic.

Here is a site that seems to give a more realistic appraisal of the Drake equation: http://www.setileagu...es/amatseti.htm

Haven't exactly pinned down the radius of our potential observations. For diffused unfocused "beams" I see suggestion that we may be able to cover a 20 light year radius at present. Another 100 years and the radius may be doubled. If the communications are focused, though, that all becomes a mute point.

[Chip]

Oops. Maybe Drake didn't do such experiments simulating early earth conditions. One of the first such studies was done by a researcher with a name something like Cyrilponamperuma, if I remember correctly. His book was the one I read where I first learned of Drake's equation. Haven't been able to find a reference. I probably got the spelling incorrect. Still, the "Chinese box" probabilities mapping that Drake's equation describes without necessarily coming to hard data makes sense from a strictly mathematical approach.

Ah, found him. The name is "Cyril Ponnamperuma." I read one of his books in about 1974.

Edited by Chip, 27 June 2005 - 01:56 PM.

[JonesGuy]

If you assume that we've been broadcasting for about 50 years (just assume, the hard numbers aren't important), then our signal has reached some 1300 stars.

Here is a site discussing the power of our various signals

http://www.computing...y/HET608/essay/

Here is our local star environment.

http://hometown.aol.com/nlpjp/map3.htm

[John Schloendorn]

Thanks QJones,
1000 ly for focused transmissions is a good deal and together with Brian's points I think can account for the so-called Fermi paradox.

(enoosphere)
The authors present an interesting solution to Fermi's Paradox: biological lifeforms evolve in the Galactic Habitable Zone but "will tend to migrate outward through the Galaxy as their capacities of information-processing increase, for both thermodynamical and astrochemical reasons."

(bgwowk)
Any beings serious about living a long time (immortality), cannot allow the energy resources of the galaxy to be uselessly squandered away into intergalactic space over just a few billion years. Better management of the energy resources (fusionable elements) of the galaxy could permit life to continue for trillions of years.

Is not most matter in the universe actually hanging out between the galaxies, in a mysteriously dark (non-emitting) state that some say has a number of rather spooky properties? If that were alive, then the question would remain why it left some matter bright. Perhaps they need some fraction of the matter bright, in order to properly regulate the expansion of the universe or whatever...? (That's what the dark stuff is doing, isn't it?)

[Chip]

Yes, thanks QJones. I read that entire first article carefully. Will look at the other.

"Either way, humanity will have to be very lucky if current SETI strategies are to be successful, even if the Galaxy is teaming with intelligent life."

I see that this rather hard core science suggests space based interferometric processed radio telescopes would be the only feasible SETI. Only a couple diameters of earth should be necessary and, in fact, use of satellites with earth based antennae have been proved feasible and probably could be deployed quickly. As far as I can tell the gov has basically curtailed funding for SETI understandingly so due to its appearing nonfeasible as it has been pursued. So, ah, is any body pursuing the feasible approach that has been recognized in these studies? It could probably be done without a lot of expense and within a couple of years, right? Why aren't we doing it? What am I missing?

[Chip]

Looking at that star map, maybe establishing a baseline for the telescopes would best be larger than two diameters. Still, the effective radio telescope of just a couple of Earth diameters appears virtually available right now and I for one would not be opposed to time spent using those satellite(s) and Earth based arrays we already have with the couple of diameters base line. I see from a wikipedia, http://en.wikipedia....Space_Telescope that a space telescope is planned for the Lagrange 2 point in 2011 but

"Funding difficulties caused partly by the increased cost of JWST and of other NASA missions such as for Mars exploration and potential servicing of the Hubble Space Telescope mean that the JWST mission is likely to be reduced in scope.

besides its being only designed for infrared. An L2 radio telescope interferometrically conjoined with Earth based scopes would give us a huge baseline to look at a whole mess of stars with the ability to pick up the equivalent of present and past human radio and TV broadcasts from other civilizations if they were out there. I would find that a much less costly and potentially fruitful endeavor than the boondoggle mars mission which has effectively shut down much space science.

If we did get signals, not only might we learn we are not alone but we might learn a lot of new science fast to help us in our endeavors here. The pay off for a L2 radio telescope might be inestimably huge.

[Chip]

The more I think on this the more I like it. The exploration into the possible use of the sun as a magnifier of radio transmissions needs to be explored but the relatively inexpensive and what appears as entirely feasible approach to making a sufficiently large antenna appeals. VLBLI, very large base line interferometry is a proven technology. I've toured the VLA, very large array, in New Mexico. I strongly suspect it would be greatly less expensive than a Mars trip to put two communication frequencies radio telescopes at a couple of the Lagrange points. Seems then, the mathematics points to a likelihood of receiving intelligence from other life systems. That intelligence could very well be the key to approaching immortality with the lives we have now.

One problem, human social institutions do not seem capable of choosing cognitive science, witness the creationists holding office. It is the mathematics of evolution that suggests we are not alone. The evidence of the deployment of life here tells us it has done so elsewhere. We either unite with it and stand or, divided we fall.

The expectations of life elsewhere determine what size antenna is needed. Looks like this results in considering a base line of four earth diameters. Current SETI is a joke. The Lagrange points give us a place to have stationary observation points far in excess of this, 30 Earth diameters and more, likelihood almost becomes certainty. I suppose we could have one on the moon too but the Lagrange points would be cheaper and easier to use. It could happen soon, within the next decade.

Where is the advocacy group I can assist with donations or what not that sees the fantastic and incredible value such a project promises?

[1arcturus]

I think it's likely that radio transmission will be superseded as a means of interstellar communication because WE can see how impractical it is - slow, nonprivate, wasteful of energy. If we can see how impractical it is, and how much better it would be if we had some better means of communication, then it follows that we will work on developing this superior communication until we do develop it. And if any alien civilization similar to ours preceded us, then they will already have done it. We're like savages wondering why those folks in the cities don't use smoke signals and drum codes.