To deal with the cognitive dissonance created by the Great Silence, we have resorted to good old fashioned human arrogance, anthropocentrism, and worse, an inter-galactic inferiority complex. We make excuses and rationalizations like, ‘we are the first,’ ‘we are all alone,’ or, ‘why would any advanced civilization want to bother with us backward humans?’
Under closer scrutiny, however, these excuses don’t hold. Our sciences are steadily maturing and we are discovering more and more that our isolation in the cosmos and the dearth of observable artificial phenomenon is in direct violation of our expectations, and by consequence, our own anticipated future as a space-faring species.
Indeed, one of the greatest philosophical and scientific challenges that currently confronts humanity is the unsolved question of the existence of extraterrestrial intelligences (ETI's).
We have yet to see any evidence for their existence. It does not appear that ETI’s have come through our solar system; we see no signs of their activities in space; we have yet to receive any kind of communication from them.
Adding to the Great Silence is the realization that they should have been here by now -- the problem known as the Fermi Paradox.
The Fermi Paradox
The Fermi Paradox is the contradictory and counter-intuitive observation that we have yet to see any evidence for the existence of ETI’s. The size and age of the Universe suggests that many technologically advanced ETI’s ought to exist. However, this hypothesis seems inconsistent with the lack of observational evidence to support it.
Largely ignored in 1950 when physicist Enrico Fermi famously asked, “Where is everybody,” and virtually dismissed at the seminal SETI conference in 1971, the conundrum was given new momentum by Michael Hart in 1975[1] (which is why it is sometimes referred to as the Fermi-Hart Paradox).
Today, 35 years after it was reinvigorated by Hart, it is a hotly contested and relevant topic -- a trend that will undoubtedly continue as our sciences, technologies and future visions develop.
Back with a vengeance
A number of inter-disciplinal breakthroughs and insights have contributed to the Fermi Paradox gaining credence as an unsolved scientific problem. Here are some reasons why[2]:
The scale of our cosmological environment is coming into focus. Our Universe contains about 10^11 to 10^12 galaxies, giving rise to a total of 10^22 to 10^24 stars[3]. And this is what exists right now; there have been a billion trillion stars in our past Universe. [4]
Improved understanding of planet formation, composition and the presence of habitable zones
The Universe formed 13.7 billion years ago. The Milky Way Galaxy formed a mere 200 million years later, making our Galaxy nearly as old as the Universe itself. Work by Charles Lineweaver has shown that planets also began forming a very long time ago; he places estimates of Earth-like planets forming 9 billion years ago (Gyr).
According to Lineweaver, the median age of planets in the Galaxy is 6.4+/0.7 Gyr which is significantly more than the Earth’s age. An average terrestrial planet in the Galaxy is 1.6 Gyr older than the Earth. It is estimated that three quarters of earth-like planets in the Galactic habitable zone are older than the Earth.
We have a growing conception of where habitation could be sustained in the Galaxy. The requirements are a host star that formed between 4 to 8 Gyr ago, enough heavy elements to form terrestrial planets, sufficient time for biological evolution, an environment free of sterilization events (namely super novae), and an annular region between 7 and 9 kiloparsecs from the galactic center that widens with time. [6]
The discovery of extrasolar planets
Over 240 extrasolar planets have been discovered as of May 1, 2007[7]. Most of these are so-called “hot Jupiters,” but the possibility that their satellites could be habitable cannot be ruled out. Many of these systems have stable circumstellar habitable zones.
Somewhat shockingly, the first Earth-like planet was discovered earlier this year orbiting the red star Gilese 581; it is 20 light years away, 1.5 times the diameter of Earth, is suspected to have water and an atmosphere, and its temperature fluctuates between 0 and 40 degrees Celsius.[8]
Confirmation of the rapid origination of life on Earth
The Earth formed 4.6 Gyr ago and rocks began to appear 3.9 Gyr ago. Life emerged quickly thereafter 3 Gyr ago. Some estimates show that life emerged in as little as 600 million years after the formation of rocks.[9]
Growing legitimacy of panspermia theories
There is a very good chance that we inhabit a highly compromised and fertile Galaxy in which ‘life seeds’ are strewn about. The Earth itself has been a potentially infectious agent for nearly 3 billion years.
Evidence has emerged that some grains of material in our solar system came from beyond our solar system. Recent experiments show that microorganisms can survive dormancy for long periods of time and under space conditions. We also now know that rocks can travel from Mars to Earth.[10]
Discovery of extremophiles
Simple life is much more resilient to environmental stress than previously imagined. Biological diversity is probably much larger than conventionally assumed.
Developing conception of a biophilic Universe in which the cosmological parameters for the existence of life appear finely tuned
As scientists delve deeper and deeper into the unsolved mysteries of the Universe, they are discovering that a number of cosmological parameters are excruciatingly specific. So specific, in fact, that any minor alteration to key parameters would throw the entire Universe off kilter and result in a system completely unfriendly to life. The parameters of the Universe that are in place are so specific as to almost suggest that spawning life is in fact what the Universe is supposed to do. [11]
Cosmological uniformitarianism implies that that anthropic observation need not be and cannot be specific to human observers, but rather to any observer in general; in other words, the Universe can support the presence of any kind of observer, whether they be here on Earth or on the other side of the cosmos.
Confirmation of the early potential for intelligent life
My own calculations have shown that intelligence could have first emerged in the Universe as long as 4.5 Gyr ago -- a finding that is consistent with other estimates, including those of Lineweaver and David Grinspoon.[12]
Refinement of evolutionary biology, computer science and systems theories
Evolution shows progressive trends towards increasing complexity and in the direction of increasing fitness. There has also been the growing acceptance of Neo-Darwinism.
Advances in computer science have reshaped our conception of what is possible from an informational and digital perspective. There is the growing acceptance of systems theories which take emergent properties and complexity into account. Game theory and the rise of rational intelligence add another level to this dynamic mix.
Development of sociobiological observations as they pertain to the rapid evolution of intelligent life and the apparent radical potential for advanced intelligence
Exponential change.
And then there is the theoretic potential for a technological Singularity, digital minds, artificial superintelligence, molecular nanotechnology, and other radical possibilities. There is also emerging speculation about the feasibility of interstellar travel, colonization and communication.
In other words….
There are more stars in the Universe than we can possibly fathom. Any conception of ‘rare,’ ‘not enough time’ or ‘far away’ has to be set against the inability of human psychology to grasp such vast cosmological scales and quantities. The Universe and the Milky Way are extremely old, our galaxy has been able to produce rocky planets for quite some time now, and our earth is a relative new-comer to the galaxy.
The composition of our solar system and the Earth itself may not be as rare as some astronomers and astrobiologists believe. These discoveries are a serious blow to the Rare Earth Hypothesis – the idea that the genesis, development and proliferation of life is an extremely special event[13]. It’s also a blow to Brandon Carter’s anthropic argument which takes a very human-centric approach to understanding cosmology, suggesting that our existence as observers imposes the sort of Universe that only we can observe.
Finally, the Universe appears capable of spawning radically advanced intelligence – the kind of advanced intelligence that transhumanists speculate about, namely post-Singularity, post-biological machine minds. Given intelligent life's ability to overcome scarcity, and its tendency to colonize new habitats, it seems likely that any advanced civilization would seek out new resources and colonize first their star system, and then surrounding star systems. Indeed, estimates place the time to colonize the Galaxy anywhere from one million to 100 million years.[14]
The fact that our Galaxy appears unperturbed is hard to explain. We should be living in a Galaxy that is saturated with intelligence and highly organized. Thus, it may be assumed that intelligent life is rare, or, given our seemingly biophilic Universe, our assumptions about the general behaviour of intelligent civilizations are flawed.
A paradox is a paradox for a reason: it means there’s something wrong in our thinking.
So, where is everybody?
[1] Hart, M. H. "An Explanation for the Absence of Extraterrestrial Life on Earth," Quarterly Journal of the Royal Astronomical Society, 16, 128-135 (1975).
[2] This list, which is not intended to be a complete re-affirmation of the Fermi Paradox, was inspired and partly adapted from: Ćirković , Milan M. and Bradbury, Robert J. "Galactic Gradients, Postbiological Evolution and the Apparent Failure of SETI", New Astronomy, vol. 11, pp. 628-639 (2006).
[3] "How many stars are there in the Universe?" European Space Agency, Space Scientist, February 23, 2004: http://www.esa.int/esaSC/SEM75BS1VED_index_0.html.
[4] Hanson, R. 1999, “Great Filter,” (preprint at http://hanson.berkeley.edu/greatfilter.html).
[5] See Harvey Mudd and S. E. Levine: “Mass of the Milky Way and Dwarf Spheroidal Stream Membership.”
[6] Gonzalez, G., Brownlee, D., and Ward, P. 2001, “The Galactic Habitable Zone: Galactic Chemical Evolution,” Icarus 152, 185-200; Lineweaver, Charles H., Fenner , Yeshe, and Gibson, Brad K. 2004, “The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way.”; M. Noble , Z. E. Musielak , and M. Cuntz: 2002, "Orbital Stability of Terrestrial Planets inside the Habitable Zones of Extrasolar Planetary Systems"
[7] "A Rush of New Planets," Astrobiology Magazine: Jun 02, 2007: http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2351
[8] "All Wet? Astronomers Claim Discovery of Earth-like Planet," Scientific American, April 24, 2007: http://www.sciam.com/article.cfm?articleID=25A261F0-E7F2-99DF-313249A4883E6A86&chanID=sa007
[9] See Stephen J. Mojzsis: http://spot.colorado.edu/~mojzsis/
[10] Raulin-Cerceau, F., Maurel, M.-C., and Schneider, J. 1998, “From panspermia to bioastronomy, the evolution of the hypothesis of universal life,” Orig. Life Evol. Biosph. 28, 597; "Encore: Great Debates Part VI," Astrobiology Magazine, Aug 19, 2002: http://www.astrobio.net/news/article254.html
[11] The Wikipedia entry on the Fine Tuning argument has some good links and references: http://en.wikipedia.org/wiki/Fine-tuned_universe
[12] Dvorsky, George: 2006, “When Did Intelligent Life First Emerge in the Universe?” http://sentientdevelopments.blogspot.com/2006/06/when-did-intelligence-first-emerge-in.html;
[13] Ward, P. D. and Brownlee, D. 2000, Rare Earth: Why Complex Life Is Uncommon in the Universe (Springer,
[14] Ćirković ,
99 comments:
Absence of evidence is not evidence of absence.
Here's another line of thought, how long would it take intelligent life to colonize the Galaxy? Pulling a number out of ... the air, let's say 1 million years. That's enough time, given exponential exploration, even for generation ships to do the job, let alone other stuff. So, intelligent life has been possible for 4.5GY. That's enough time for the Galaxy to have been colonized 4,500 times over. Where, indeed.
It's not even just our galaxy. Assuming that a galaxy-spanning civilization would have some sort of enormous energy requirements, it's reasonable to think that some such civilizations would generate that energy in a way which would modify their galaxy's spectrum, even if just by enhancing black-body relative to stellar features. Yet is anyone aware of *any* galactic spectra which differ markedly from explained natural processes in a way which suggests "manufactured" processes?
We see no evidence of past visitations to our solar system, but only in the grossest possible sense. Nobody built titanium pyramids at the peak of Olympus Mons or on the Canadian Shield. Nobody carved their kilometers-long initials on the moon.
The kind of low-level detritus we would expect to see from survey missions is really hard to find - and the someone who finds it has to be in the right frame of mind to interpret and preserve it correctly anyway, and not just toss it aside.
There are plenty of accounts of metallic oddities found in coal seams, but even if someone actually found something like that today they're not going to shut down production on a commercial coal mine for a week just to preserve a single bolt that has shown up in the wrong place.
My point is just that you can't make the statement that we've seen no evidence within the solar system for visitations - even if such evidence exists it cannot be realistically preserved or utilized.
Their presence here wouldn't have been subtle; the entire solar system would have likely been worked over and re-organized -- including the uplift of all life.
The thought that other worlds exits other than our was also put forth by the architect behind Washington DC, a man by the name of Benjamin Banneker. Banneker was a astronomer who postulated that because of the apparent reproduction in many natural forms, spirals representative in the Fibonici sequence, there must be ETI.
In a Ken Wilber interview called A Ticket to Athens it is postulated that Spirit/Tat Tvam Asi/God manifests a world for the pure fun of being among others.
As painful a place as earth is, with the torment we inflict upon one another, it may still be our best chance for joy.
What good would it do for The All to spoil things and say "Here I am," ending all the malarkey?
Ooops. I forgot to get to my point. My point is that surely life that is most advanced is also highly spiritually advanced and, thus, has enormous wisdom and compassion.
Perhaps the wisest, most compassionate thing to do is shield us from other life and to allow us to further evolve until we reach some threshold where other life announces its existence and welcomes us into another kind of life, one where trauma and drama is much reduced and all the stress we now feed on greatly abates.
I have a theory, but you wont like it.
Our development has shown that even the most rudimentary forms of intelligence lead to the pursuit of ever greater power. This can be seen in chimps, but has been taken to a extraordinary levels by humans. The only way we can currently detect extraterrestrial life is through radio waves. It is no coincidence that for us, nuclear power came at almost the same time as radio waves. Optimists might point out that we haven't annihilated ourselves yet, but pessimists will counter that evolutionarily we have only had that power for an fraction of an instant - and far more destructive powers are in the pipeline and likely to be released very soon.
If you observe human development objectively, I believe you will come to the conclusion that we seek and gain power faster than the gain the maturity to use it wisely. In a few short decades, humans have created (or are soon to create) the following risks: nuclear armageddon, biological agent armageddon, global climate armageddon, global ecological armageddon, overpopulation armageddon, GMO armageddon, nanotech armageddon... you get the idea. However low these risks are, they are mounting, and it is just a matter of time. I think it is reasonable to assume that any extraterrestrial lifeform would have evolved to have a similar desire for power. Maybe intelligence inevitably leads to self-destruction. Maybe the 'wow' signal was the last moment of some galactically local civilisation in the process of self destruction.
Before you dismiss this as simply depressingly pessimistic, don't forget that pessimists have been scientifically shown to have a more objective view of reality than normal 'happy' people.
You ask the question "Why would any advanced civilization want to bother with us backward humans?" and yet you also refer to the Singularity.
Post-Singularity civilizations really wouldn't be that interested in talking to us; they would know that we would be much more interesting in a matter of years.
Worse yet: Perhaps post-Singularity civilizations have their own Singularities. I.e., even after we become more advanced, our neighbors may have transcended yet another plane.
The problem here is that you must consider the time frames in which evolving civilizations are within similar technological windows--and therefore have enough relevant interests to communicate. It seems unlikely that comparable civilizations will co-evolve within a distance smaller than that of our current technological ability to communicate.
Who is to say that a post-Singularity civilization would be interested in colonization of anything other than enough local space to guarantee resiliency against catastrophe? Its motives, by definition, would be inscrutable from our perspective.
Here is an idea that might resolve the Fermi Paradox which I don't seem to have seen mentioned anywhere yet:
In the theory of eternal inflation there is something called the "Youngness Paradox", (see, e.g., this
viewgraph from a talk given by Alan Guth which states that the society of "pocket universes" (each starting with their own Big Bang) is (in Guth's words) "incredibly youth-dominated" (therer are many, many more pocket universes which are much younger than ours than there are older ones). So, anthropic reasoning would imply that we should find ourselves in the youngest universe which is compatible with our existence, i.e., we are the first civilisation that arose in our pocket universe. Of course this kind of argument doesn't help with figuring out why it took so long for the first civilisation to arise...
I don't buy the "they aren't interested in us" argument"
No way every civilisation ever has decided to withdraw from the universe and stay in their solar system. And if they agree to not interfere, that doesnt stop us from detecting them.
Where are the dyson spheres and matrioshka brains emmiting in the Infra-Red but not the visible. Where are the stellar engines travelling through the galaxy eating othere systems to keep the star alive. Where are the galaxy spanning civ's trying to run an attack on space-time itself.
None of the answers, including the self destruction one, really satisfy the question. Why isn't someone elses singularity here yet?
Island: I rejected your comment, not because you weren't on point (I would actually welcome a discussion of the strong anthropic principle), but your post was unnecessarily abusive and absolutely uncalled for. If you want your comment published here please do so in a considerate manner.
If we assume of few things 1) that as life grows on a planet it eventually uses up all the resources and dies off, 2) intelligent life comes and goes with ice ages / climate shifts, making the existence of intelligent life a stochastic process, 3) during the evolution from atoms to molecules to life of some sort, there are millions of paths within this evolutionary manifold, which may or may not result in "life" that can communicate, 4) it is rare that a planet can support life, 5) you can't go faster than the speed of light, then in order to calculate the probability of being contacted, our society must overlap with another society precisely at the same time. Time, then, is the problem. If there's one in a million planets that can support life, with millions of failed evolutions towards life, amidst thousands of billion-year windows for life to evolve, with the chance of technological realization drastically lessened by asteroids or othere extinction level events, the independent probability of overlapping communications between two societies is infinitessimal. And since nothing goes faster than light, the chance of one civilization being around to send and receive a signal across the universe (i.e., the definition of communication) is correlated to the distance between civilizations. So not only do these rare events have to happen, but they have to happen relatively close to each other. So, I don't know what Fermi was thinking, but it certainly doesn't seem like a paradox. The other requirement is that we speak the same language using the same communications techniques. Let's just stop there...
What happens when science continues to ignore the evidence that it finds (or doesn't find in this case)? Are we no longer operating in the realm of strict science, but on a belief, hunch, or hope?
The question "Where are they?" raises a more important question - "Where is science?"
You are right. There is a problem with thinking. One can easily solve the paradox by implying that evolution of the intelligence does not necessarily mean constant improvement of the technology or galactic expansion.
In a galaxy in which civilizations have developed technologically as far as possible, the most valuable comodity of all would be new informaiton. Even in our world, content is king. Is it possible that we are being intentionally cut off from the rest of the universe just so that we can create new art, music and history? Are we a kind of reality show that the rest of the universe can watch for their own enjoyment?
One reason (albeit a cruel one) is that there simply is no solution to the faster-than-light travel problem. No warp drive, no hyperspace, no stargates, nothing.
If all of the sentient species in the universe were effectively isolated from each other, than your only means of contact would be via radio...and finding such signals amid the vast sea of noise that permeates our universe has proven to be very hard indeed...
What "discussion" George? Historically, I make a statement of fact about the anthropic principle, you say nothing, and then later I find you making the same false statements again.
I can't imagine why you'd expect me to be nice about that, but here goes nothin...
The *alleged* Fermi Paradox is resolved by the Goldilocks Enigma.
The simplest answer is a rather nasty one, which is that the Big Bang was caused by some 7-armed nuclear physicists with a really big particle collider and plenty of hubris looking for the God particle. Well, they found it.
One of the assumptions being made is that a sufficiently advanced civilization would naturally want to expand to other star systems. But it may be that interstellar travel just doesn't make sense economically.
The energy budget needed to send even a reasonable-sized payload to another star is staggering - to accelerate an object to .9c you'd have to burn 10 tons of matter/antimatter for each ton of payload. Longer trips are cheaper, but they also require more investment in preserving the payload over time spans of thousands of years. And yes, there are plenty of science-fictional workarounds for this, but they may not be practical.
Even if you do succeed in colonizing another planet, what does it get you other than a warm fuzzy feeling knowing that there are others of your kind out there? You can't effectively trade with them, and communication is similarly limited.
If expansion outward was the only kind of expansion available, then I might see that even with all these difficulties, a planetary civilization might dedicate a significant fraction of its energy budget to it.
However, a much richer and more interesting path is available to a high-tech civilization, which is internal complexification and expansion inward. Soon we'll be able to create virtual planets which are far more accessible and intellectually stimulating than the ones we can reach in the physical world.
So my argument is that outer space competes with cyber space for exploration resources, and cyber space is a lot easier to get to.
What about the thought that other Species just don't bother about Space travel. Just take the endless debates here on our planet about the usefulness of Human Spaceflight.
Maybe other Species started to colonize they own Solarsystem and then stopped, because they saw no sense in going beyond.
Lets Face it Space exploration is a resource expensive thing. I could imagine that Earth-like Planets which are larger than Earth, and thus have more gravity, you would quickly come to a point where the investment of resources just do not justify the scientific results and thus decisions are made to not pursuit Manned Space Exploration.
All that would lead to a scenario where a species would not go beyond their own Solar System.
Island: My apologies if you feel you were slighted by my lack of response. I'm actually quite terrible at responding to comments -- mostly because I feel it takes me away from other work. I'm trying to be better about this, however.
That said, be nice. How can I take you seriously if you resort to hostility and name calling? You obviously don't care for my work, and that's fine. All I ask is that you be respectful.
Now, to the matter at hand, I actually consider the SAP to be a fascinating possibility, particularly in the context of time theory and recursive cosmology.
Rather than elaborate here in the comments section I'll devote an entire article to the topic. Look for this in the coming weeks.
Anonymous wrote: "Post-Singularity civilizations really wouldn't be that interested in talking to us; they would know that we would be much more interesting in a matter of years."
How do you know they wouldn't be interested in talking to us? I expect many of our historians, anthropologists, etc. would jump at the chance to talk to alien civilizations that are in their equivalent to the Bronze Age, or earlier. Is lack of curiosity some inherent quality of post-Singularity civilizations?
Not to be (too) much of a jerk about it, but after assuming something about the motivations and desires of a post-Singularity society, you went on to state that their motives are by definition inscrutable to us. ;)
Okay George, but be careful about what you think that the SAP means, because a strong interpretation isn't necessary to make my point about the observed universe, and it already appears that you think that it is, so I have to wonder...
Let me say this to illustrate the problem as it typically applies to this. I've been exclusively studying the anthopic physics for a good 6 years now, and I've yet to find anyone that thinks that it requires anything more than a quick read of somebody's website to give an "educated" opinion about it.
And it shows...
There are several options.
For example, current technology is advancing at such pace that common analog radio technology might well obsolete in decades. It will all be digital. The window of time for radio detection might only be a century or so. Interstellar Communications might all be in the equivalent of "sub-space", using some form of quantum technology, and so very undetectable by our own ordinary means.
We also omit the possibility of politics. What's to say that we haven't developed in the middle of some interstellar wasteland left behind by interstellar politics gone wrong?
Don't know what's wong with you people, but aliens visit me each year.
It it possible that we are observed by intelligent life all the time, but due to our limited intelligence, we are clueless?
When you walk by an ant hill, do they know you are observing them? I have a gut feeling we think way too highly of ourselves.
Bill Martin
Cascade, MD
I am reluctant to bring mysticism to the conversation, but it's only a comment.
It would seem that the birth of a habitable planet seems tied to the will for life. As I see it, the uniting the observer with the observed. I would also explain this as the unborn infant who already owns his/her/its identity - pre-conception.
contact with eti would, to piggyback on what tom said, be a matter of our putting our spiritual house in order and then conducting ourselves in a manner to become the compassionate beings we hope to come in contact with. afterward, finding other beings of a similar age.
So, in essence, we haven't been born yet.
Really it seems to me that before we all spend lots of time contemplating philosophical reasons for this (ie anthropic principals, etc), that we just make a list of all the reasons we can imagine that other civilizations would not bother to talk to us.
Here for example is a new one (I've never heard it before anyway). They discovered the theory of everything pretty quickly and once they had ALL the answers, why would they need to talk to us? Or explore? Maybe there IS a TOE and maybe once you formulate it, then why ask any other questions?
There could be a load of other reasons. Maybe there are simpler ways to explore than in space. Maybe we can build some kind of technology to access other universes or just make anything we need, so why again would we need to move out into space?
Personally though I hold with the 'space is a very large and very hostile environment' theory. Interstellar travel VERY well may be effectively impossible. That wouldn't completely explain the lack of all signals, but it would help explain why civilizations might not last long, they will always be concentrated in one small place and vulnerable. We haven't even PROVEN we can sustain life anywhere outside the earth's biosphere for any length of time. I want to see the PROOF of that before I am surprised we aren't chatting with LGMs.
Other than math and science, here is another discipline that should be brought into the discussion - history. The history of our race believing that we understood something so (nearly)completely that we were ready to come up with a definitive answer when in fact we had much to learn.
Yeah sure, we're scanning the sky and finding nothing, but as a previous commenter stated, we might not even know what to look for. 25 years from now we'll all be chuckling at how we thought we could even attempt to answer such a question.
It's just too early.
There have been many Fermi answers proposed over the years, and I see many of them listed here. Many, however, have a troublesome attribute. They posit some explanation, and then have to assert that this reason is true, everywhere in the universe, for all of the universe's history. They may posit that civilizations are self-destructive, or inward looking, and certainly some would be.
But all of them? Alas, our only example is of an expansionist, colonizing life form that, so far, has not destroyed itself. It's a huge leap to suggest that every different civilization that might have arisen out there follows the same rules. That's a premise you must defend with more than assertion.
Suggestions that we are the first don't have this flaw (though they have other flaws.) Suggestions that we are in a protected zone, subject to a Prime Directive, are also more credible because that only requires that this is an attribute of the particular race in charge of this particular area.
However, it becomes a more complex rule than you think at first, because we've searched the visible galaxies and found no evidence of galactic scale engineering, anywhere. So the zookeepers would have to be presenting us a false sky -- though this is not out of the realm of possible situations.
We search the universe for life like we search a year book for our own picture. We don't find life in the universe, because "we" are not out there. I doubt "they" are anything like us. If "they" were standing right next to us, I doubt we'd recognize them.
I think it's ridiculous to say we've never been visited and are not currently being visited by advanced civilizations.
The day we do realize it, will likely be a sad one. Anytime an advanced civilization interacts with a new born, innocence is lost, a lot of what makes the civilization unique is lost as well.
When is the last time an advanced human interacted with an ant hill, that went well for the ants?
The Fermi Paradox reminds me very much of the Kafka's "Before the Law" parable: http://www.herzogbr.net/kafka/beforethelaw.htm
What if this universe is made only for us?
One question I've never seen answered - do gamma-ray bursts cause any disruption within electronics? If they do, maybe that is an equally limiting factor on post-biological civilizations as well as biological ones.
I think, too, that maybe they don't want to be discovered.
I mean, maybe our planet is in some sort of quarantine or "nature preserve." I think that our civilization is at a critical juncture. We have developed the capability to be truly dangerous to ourselves and possibly even other civilizations (especially with things like nuclear and biological weapons/genetic engineering) but not necessarily, as has often been observed, the maturity to decide what to do wisely. It may be that they are concerned (probably wisely) that knowledge that we are not alone could push us over the edge to self-destruction.
Or it could be that they ARE interested but they don't want to disturb us. Basically, trying to avoid Heisenberg's Uncertainty Principle on a social scale, observe us without tainting the results by their presence. Or does anyone remember that Jim Carey movie The Truman Show?
I don't know if our civilization followed a fairly typical path or not. If we did then it may even be a standard practice to institute this sort of quarantine at a certain point in an upcoming civilization's development for our own protection as well as that of everyone else. Maybe they've had enough species that aren't mature enough to handle it go on a killing spree if first contact is made too early; with the result that they then have to be put down like a rabid dog and they really don't like genocide or near genocide. Or maybe we just developed more than normal aptitude of making war (anyone ever read Alan Dean Foster's The Damned series?) and it's a precaution.
Anyways, yeah, my point is that I have to think that maybe they just don't WANT to be found. I'm sure any sort of interstellar civilization would likely have capabilities of which we can only dream, including the ability to make sure that we don't see them until they're good and ready for us to.
Personally, I like the solution that Charles Stross presented in Accelerando: that a post-Singularity civilization would choose to stay near its home star to conserve bandwidth and energy (along with the common statement that, by definition, we'd have nothing to talk about with such a civilization).
I am bothered, though, that not only do we see no direct signals, but we see no signs of large-scale alteration of astronomical-sized objects. If there's a Matrioshka brain within a hundred light-years, we ought to be able to detect it. (Though I'm not convinced that anyone would actually build such a large computer, due to the latency issues.)
There is a huge difference between the testable predictions that fall from the directly observed physics that derives the goldilocks enigma... ... ...
... ... ...and the the what-if, woulda'-coulda'-shoulda' speculation that is being put forth in its place.
The first, is the real sceince that provably derives the habitable zones, ecobalances and WMAP anomalies of our observed universe, whereas the latter is nothing more than speculative science fantasy, until the actual science that we have at our disposal is falsified by some hard evidence.
That isn't to say that I haven't seen some decent speculation in this thread, but that's all it is without some equally hard evidence.
Read Stephen Webb's "Where is Everybody?" for 50 possible solutions to the Fermi Paradox. They range from the humorous to the plausible. ISBN: 0387955011
I think the answer lies in the patterns that we have observed and learned over the years. Basic things like physical laws and others like Fibonacci sequences which pop up in things from Sunflowers to the Stock Market. Then consider the growing awareness of interconnectivity, from the environment to Bell’s Theorom. Why would interstellar life be any different? There must be a connection; it’s just that we haven’t found the correct paradigm. Remember, and I hate to say it, but it’s so true – As above, so below…
Since Fermi first proposed the paradox, and Drake stated his equation, we've been able to make some of the factors more precise (as the original posting points out), but some of them are just as unsure as ever. I think the biggest gaps are (1) how likely is technological intelligence likely to arise, and (2) how long to civilizations last?
We have only one clear example of intelligence evolving, and it took 4G years. How many species have reached the clever-animal stage and stopped there, because further intelligence would not have been selected for? There are plenty of clever mammals, birds, even invertibrates, which seem well suited for their environment. Maybe the evolution of homo sapiens in the last few million years in Africa was an extremely unlikely event? How can we know?
The other question is how long our civilization will last. I tend to be an optimist and hope that it will survive its current rough patch, but who knows?
Also, maybe interstellar travel is *really* hard and not worth the trouble for any sufficiently advanced civilization. Hard to imagine if you've grown up watching Star Trek but maybe by the time we could possibly send out generation ships or whatever the best way is, it won't be worth the trouble.
I want to address several things:
1. we cannot deny existence of paradox. Because if we do any discussion of it is simply ludicrous and a waist of time.
2. as far as we know (from empirical evidence) universe is uniform, and because of this we have no basis to say that any other planet like (or rather environment like) Earth would be any different from ours. So if there are Earth-like planet with about the same age, then it should have species with the same level of technology (plus/minus due to catastrophes. geography, etc). And all this with complete disregard for non-carbon life, possibility of some life on non-earth like planets, etc., etc..
3. Extrapolating from our own evolution we can say that we need to expand in order for our species to survive, and we need to expand beyond a single solar system in several billion years time-period.
4. Having the right technology our population grows very rapidly, so there is no reason why our exploration should stop after we colonize next available star system.
We built a spacecraft capable of leaving our solar system many years ago. And it's only a technological question of building a bigger one. We can produce a self-sufficient ecosystem, it's not a complicated task. More than that, with all the stem cell research we can probably just grow food by multiplying existent cells.
So we can start space colonization very soon. There are no problems, that we can think of us unsolvable. And that's only us. Now if we imagine that millions of years ago there were some planets with much better societies with greater respect for science (which is not hard to imagine), then they should be around. And they are not.
Saying that They were destroyed from within or never existed, never reached space travel etc. does not solve paradox in any way. It's just a denial. Because you can as well argue that they could survive, could reach, could be here by now. Do paradox lives on.
Fermi Paradox is nothing more than extrapolation of our own evolution. And it can be that the reason why we can't find anybody out there, is because maybe our own evolution takes another turn in a near future. It does not stop, we don't die, we don't kill planet, we might not even stop technological development. But something happens that we don't consider at this moment. Not because it is incomprehensible, but because we just didn't look at the nature this way yet.
I really don't buy the basis of the paradox - there is only a paradox in the first place provided that you accept some utterly naive extrapolations of current logarithmic growth into an indefinite future - the "singularity" for one ridiculous example, or galaxies with all their suns surrounded by matrioshka shells, or similar nonsense.
These are not necessary or inevitable conclusions to technological development - they in fact fly in the face of real experience and practical intuition. I will allow that under the kinds of models which conclude with whole galaxies settled in a million years or so, we certainly should already be settled. That we're not seems much more likely to me to represent a failure of the naive assumptions in the models than it is any kind of informative result about the universe.
Personally I think terms in the Markov Chain represented by Earth's history of major evolutionary innovations are a better model for the distribution of life - to wit billions of bacteria worlds, a much smaller number of plant-and-barely-macroscopic-squirmy-thing worlds, a very tiny number of planets where great herds of wildebeest-things sweep across the plains, and an utterly tiny proportion of sentient worlds.
I think the answer to the paradox is simple enough: lack of data and rash unjustified assumption. While we know the ages of the stars and rocks around us--all the things we can measure from a far,--we ruin it all by making a brash unjustified assumption in a critical area. We have only one single data point for the time it takes for the evolution of intelligent life on a planet that can support it. Just one and one only. And any scientist or otherwise intelligent, learned person will tell you it is awfully dangerous to take one random point and assume its position in a field of unknown data. What if life here evolved with far above average speed and with few diversions--thanks to meteor intervention? Fro example, it is if someone went to Boise Idaho a few weeks ago, measured the air temperature at 102 degrees F and assumed that to be the annual mean mid-day temperature. They could no be more wrong. And that is for a range that lies within one order of magnitude. Evolution takes millions, even billions, of years. And order of magnitude of error there is of substantial significance on a human life span scale. So i think there is no paradox at all. Just a confirmation that we are an anomaly waiting for the rest of the galaxy to catch up.
Do you think http://muq.org/~cynbe/thoughts/bricks-in-the-wall.html is relevant?
Hey,
There's a small typo--At one point (extremophile paragraph) the text reads "more much larger."
Great article,
H
Firstly, I would suggest that 'Earth-like' planets formed 9 billion years ago would have a significantly smaller concentration of heavy elements in their crust than Earth. This would impact the development of life and technological civilisation.
Secondly, life on Earth started early but stayed mono-cellular for the vast majority of time. Maybe multicellular life is rarer than we think.
Thirdly, without the moon there would have been almost no inter-tidal zone hence a much reduced chance of life colonising land. As it was it took a long time anyway.
If any of these, or other, factors delay the development of intelligent life by a few billion years then it will not happen before the planet becomes uninhabitable.
There is not enough information available to make Fermi's idea a Paradox.
The answer could be that, somewhere along the line, there is a technological development that causes extreme, inescapable destruction. It gives no warning, and when the proverbial flint hits the steel for the first time, it's all over. Maybe this accident is what causes stars to collapse.
Any type of civilization would eventually succumb to this type of destruction, as it is totally unpremeditated.
"blog comments are worthless." however i'd like to thank you for the phrase "cosmological uniformitarianism" as it will help me be less of an idiot ["unknown knowns"]
I need to correct my previous comment:
It turnd out that the argument I made relating the Youngness Paradox of the eternal inflation theory to the absence of other advanced civilisations was made by Alan Guth himself, see e.g. his 2007 paper Eternal Inflation and its Implications.
I think there are two solutions two the paradox: Transcendence, or Destruction.
It's really hard to say which is correct. One one hand, we know that there may yet be thoughts and technologies that render our current view of ourselves with a virally-spreading and matter consuming space-faring future as the ultimate to be irrelevant. Maybe all sentient intelligent species one day find a way of life that is utterly different, and does not result in the byproducts we imagine we would find to prove their existence.
(I doubt this would be philosophical, as there would be so many varieties of this going about that someone surely would slip through)
Equally possible sounds the possibility of Destruction. Maybe all intelligent life will destroy itself when it unlocks the secrets of physics, and is able to extract energy on a level we cannot even imagine today. What if in the black depths of physics lurks the ability to create a detonation so powerful that if would blow a massive hole in a Earth sized planet, an all it required was a glass of water and a few tools.
I rememver the truly excellent book "Revelation Space", where Author Alastain Reynolds suggests that as the young life of the universe took to the stars in it's early life, they encountered each other. In the end, their competition for metal and matter resulted in wars of unimaginable scales. Nobody really won this war, but to end it, someone constructed a self-replicating machinery that spread out through the galaxy with only one purpose: to destory emerging life, and prevent such a conflict from ever occurring again.
Well well...
Judging from past progress though, I bet our current debate will seem very uninformed an derailed in 500 years (: Maybe we're just not thinking the right thoughts.
we dont have to go very far to answer this if only we were to postulate that we are the forefront of the alien expansion in the Universe and that so far we have only just begun to explore beyond out planets ..
What if WE are the galactic colonization?
If intelligent life first began 4.5GY ago and they were smart enough not to blow themselves up, they must have been really careful about how they go about colonizing the universe.
What if they take the easy way? Spew microbial seed rocks to every corner of the universe and then just wait?
They don't contact us because they already know what we are, how we think etc.
They don't contact us because there is no point in doing so.
Putting aside the fact that communication would be near impossible.
Consider the lag...
The amount of knowledge to be gained by a SLOW conversation with a virus (in evolutionary terms. That is, we are as evolutionarily challenged to them as viruses are to us. And still potentially lethal.) is practically zero.
And about the anthropic principle:
I am in favor of the idea that as complexity in the universe increases the chance for the existance of life increases.
I think that the second law of thermodynamics can be applied to any system on any level. So if entropy (complexity) is increasing on all levels. Isn't life just another manifestation of said entropy and a means of further increasing it?
I wonder if we would recognize intelligent life if we saw it? It may be unreasonable to expect that it would be existing in either a similar time scale, or a similar size scale to ourselves.
What if other civilizations are existing at the sub-atomic level? Or what if we are at the sub-atomic level to them, and all of the planets, stars, and galaxies are but the quarks and leptons of a single atom of a much larger being?
What if other civilizations perceive time much more slowly than we have, and our existence has not even registered with them yet? Or else, what if they perceive it much more quickly, and they rise and fall over and over again in less than the time it takes to blink our eyes?
What if other beings and civilizations exist in the electromagnetic spectrum as radio waves? Or as light? Or as gravitational forces? Would they even be aware of us? Perhaps our electronics are killing them off every second?
Let us always consider that alien life may, indeed, be ALIEN.
Great Article.
Each galaxy should be considered a test tube for intelligent life. The math does not exist to calculate the probability for other planets with moons or stars with habitable zones for planets that could produce life.
Researcher At VisionAndPsychosis.Net
There must also be lots of reasons why we dont see much life.
Earth has been a playground for bioligy a long time, why in most of its time didnt something like human inteligence arrived.
Most of the time grass eaters and meat eaters existed..
Other reason, yes there are lots of stars but how many star system are in a friendly environment. if there was a sudden super nova nearby live would cleared at earth.
Keeping this in mind lots of stars around centers of galaxies would be poor places for life support.
We think of radio transmissions as a method of communications, perhaps better methods exist. for example entangled light communicatoin.
how about climates turn ugly chance ?
Maybe "intelligent" life is never sustainable?
It's an old mistake to think of "intelligence" as a good thing in evolutionary terms. In fact it's just another thing.
It makes for very effective generalised exploiters of resources in the short term. However, such skills may well alwys result in unsustainable over-consumption, or in mistaking our perceived interests with actual evolutionary survival.
I think there's a good chance that "intelligence" is normally an evolutionary dead end. Such abilities may evolve frequently, but species may only be technologically sophisticated for a century or two before using up resources, or becoming too dependent on technology to adapt to new and unforseen evolutionary pressures.
Even if such flowerings of intelligence have been widespread in space, in order for us to meet up, we need to overlap in time as well. If we each get only a few decades of technological sophistication, it's not surprising we seem to be alone. Just now we probably are, at least in this bit of the Universe.
Happy days!
John Faithfull
Hunterian Museum
University of Glasgow
Okay George, now for SAP.
My theoretically supported speculation is that life is quite common within the habitable zones because intelligent life is a physically necessary feature of the thermodynamic dynamics of the universe.
The goldilocks enigma says that we all arise at the same time in the history of the unvierse though, and theory says that it's all for the same reason... which is our technological cabability to directly affect the gravity and symmetry of the universe. The cosmological model that I use says that "anonymous" might not be too far off from the truth, since pair production from vacuum energy significantly increases tension between ordinary matter and the vacuum, and eventually... something will give if a "needle-balloon" effect doesn't get us there first.
12:01 PM Anonymous said...
The simplest answer is a rather nasty one, which is that the Big Bang was caused by some 7-armed nuclear physicists with a really big particle collider and plenty of hubris looking for the God particle. Well, they found it.
boom
Another depressing reason for the non-detection of extra terrestrial civilization might be that the environment around our system is extremely hostile. Given sophisticated enough weapons systems, any detection at all might result in destruction.
Of course, in a scenario like this our abundance of radio emissions in the last century might very well have been intercepted, although the combatants have yet to respond to this new civilization.
It is imperative that we realize that any civilization capable of distant space travel is far beyond our technological capabilities. Having said that, it is logical to conclude that they would be capable of eluding any of our most advanced detection systems, considering their overwhelming technological superiority.
We will never find evidence of their presence unless they allow us to do so.
First of all, why does no