August 4, 2007

The Fermi Paradox: Back with a vengeance

This article is partly adapted from my TransVision 2007 presentation, “Whither ET? What the failing search for extraterrestrial intelligence tells us about humanity's future.”

The Fermi Paradox is alive and well.

As our sciences mature, and as the search for extraterrestrial intelligence continues to fail, the Great Silence becomes louder than ever. The seemingly empty cosmos is screaming out to us that something is askew.

Our isolation in the Universe has in no small way shaped and defined the human condition. It is such an indelible part of our reality that it is often taken for granted or rationalized to extremes.

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]:

Improved quantification and conceptualization of our cosmological environment
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]

The Milky Way itself, which is considered a giant as far as galaxies go, contains as many as 400 billion stars and has a diameter of 100,000 light years.[5]

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. Moore’s Law. Kurzweil’s Law of Accelerating Returns. Steady advances in information technologies. Artificial intelligence. Neuroscience. Cybernetics, and so on.

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?

Part II: The Fermi Paradox: Advanced Civilization Do Not...

Part III: The Fermi Paradox: Possible Solutions and Next Steps

[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:

[4] Hanson, R. 1999, “Great Filter,” (preprint at

[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:

[8] "All Wet? Astronomers Claim Discovery of Earth-like Planet," Scientific American, April 24, 2007:

[9] See Stephen J. 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:

[11] The Wikipedia entry on the Fine Tuning argument has some good links and references:

[12] Dvorsky, George: 2006, “When Did Intelligent Life First Emerge in the Universe?”;

[13] Ward, P. D. and Brownlee, D. 2000, Rare Earth: Why Complex Life Is Uncommon in the Universe (Springer, New York). Lineweaver, Charles H., Fenner , Yeshe, and Gibson, Brad K. 2004; Grinspoon, David, Lonely Planets, Ecco; 1st edition (November 4, 2003).

[14] Ćirković , Milan M., 2003: "On the Importance of SETI for Transhumanism." As it pertains to reframing the Fermi Paradox, Ćirković recommends Lytkin, Finney, and Alepko (1995; for Tsiolkovsky), Jones (1985; for Fermi), Viewing (1975), and Hart (1975), (Tipler 1980), Boyce (1979).


Anonymous said...

Absence of evidence is not evidence of absence.

Anonymous said...

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.

Anonymous said...

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?

Anonymous said...

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.

George said...

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.

Anonymous said...

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.

Unknown said...

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?

Unknown said...

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.

Unknown said...

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.

Anonymous said...

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.

Anonymous said...

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...

Anonymous said...

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?

George said...

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.

Anonymous said...

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...

Anonymous said...

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?"

monomyth said...

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.

GrangerFX said...

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?

Unknown said...

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...

Unknown said...

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.

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.

Talin said...

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.

Anonymous said...

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.

George said...

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.

Alan McIntyre said...

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. ;)

Unknown said...

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...

Sickmind Fraud said...

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?

Anonymous said...

Don't know what's wong with you people, but aliens visit me each year.

Unknown said...

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

Voodoo Logic said...

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.

Unknown said...

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.

Unknown said...

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.

Anonymous said...

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.

Anonymous said...

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?

Unknown said...

The Fermi Paradox reminds me very much of the Kafka's "Before the Law" parable:

What if this universe is made only for us?

Anonymous said...

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.

Avatar28 said...

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.

brianeisley said...

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.)

Unknown said...

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.

Jim Brewer said...

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

foo foo said...

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…

Wayne Christopher said...

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.

monomyth said...

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.

CBB said...

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.

Unknown said...

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.

Anonymous said...

Do you think is relevant?

sevenfactorial said...


There's a small typo--At one point (extremophile paragraph) the text reads "more much larger."

Great article,

Anonymous said...

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.

Anonymous said...

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.

Anonymous said...

"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"]

Anonymous said...

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.

Knut Sindre said...

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.

Anonymous said...

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 ..

Anonymous said...

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?

Anonymous said...

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.

Anonymous said...

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

Anonymous said...

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 ?

John Faithfull said...

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

Unknown said...

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.


Anonymous said...

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.

Unknown said...

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.

asahel said...

First of all, why does no one consider that we could be the only intelligent life in the universe? What is so bad about that? That is what the evidence shows, even though everyone seems to be fighting against it.

Secondly, we have absolutely no idea how life began. Panspermia is just a cop-out to remove the problem to somewhere else in the galaxy. Both DNA and RNA are so complex that they could not have arisen spontaneously in any way. The processes that surround them are so complex also (search for topoisomerase II) that DNA and RNA could not have "evolved" from simpler molecules.

The fine tuning of the universe is important:
Let's look at the universe ... It could have been designed so that you could change the universal gravitational constant or the speed of light by a 25% with no serious effects. It could be set up so that there is a huge range for the values of physical constants and yet it would still produce galaxies, stars, planets, water, and support life. However, the universe is NOT set up that way. It is set up so that there is an unbelievably miniscule range of values that physical constants must have in order for life to exist. Obviously if they weren't exactly in these tiny ranges then we wouldn't be here (anthropic principle). But the fact is that the universe is set up in this very peculiar way.

Now, if you were an alien intelligence setting up a universe so that its inhabitants would be able to tell that it had been artificially created, what would your universe look like? I submit that it would look exactly like the one we have. At least one assumption needs to be made: that the inhabitants learn logic and reason and use this rather than some other method (emotions, psychic powers,...) to explore the universe. This restricts the universe, that you, the alien intelligence is creating, to being put together in a logical way with unchanging physical laws throughout the universe, or if they do change they would have to change in way that can be understood - not chaotic randomness.

So, what about it? How would your universe look if you wanted it to look like an artificial creation to planet bound creatures?

I believe that both DNA and the universe as a whole are signs of extra-terrestrial intelligence. Now, how can you contact an intelligence that exists outside of the universe?

Anonymous said...

Just a thought... what if one ET society evolved that was truly xenophobic. Further, what if they decided to seed the universe with self-replicating robots designed to search the universe by expanding in numbers and destroying everything that is not the same as their creators? I'm not seriously proposing this has happened, but it might explain why we don't see anything. Those that haven't already been destroyed, would soon learn to keep a low profile. In which case broadcasting out into the cosmos as we do is a pretty dangerous thing to do. I could imagine an ET society 40 light years away shaking their heads and saying "Sssshhhh, you idiots. They'll hear you!"

Anonymous said...

Until someone can demonstrate that we can travel to another star it is impossible for the Fermi Paradox to be nothing more than speculation. Travel within the Galaxy is not a given. The Fermi Paradox assumes it is, but this is a huge assumption not born out by the facts. The fact is we are stranded within our solar system.

Anonymous said...

If it hadn't been for the highly unlikely impact of a Mars-sized body that caused the formation of the Moon it's likely that the Earth would have had a relatively thick crust like Venus, with possibly no tectonics and therefore no uplifting. It'd have wound up as an ocean world with no landmasses; what chance of intelligent life in such an environment?

Unknown said...

Steve M said...
Until someone can demonstrate that we can travel to another star it is impossible for the Fermi Paradox to be nothing more than speculation. Travel within the Galaxy is not a given. The Fermi Paradox assumes it is, but this is a huge assumption not born out by the facts. The fact is we are stranded within our solar system.

That's not correct;

Space travel isn't necessary for us, (and them), to travel to other parts of the galaxy via radio signals.

asahel said...
Let's look at the universe ... It could have been designed so that you could change the universal gravitational constant or the speed of light by a 25% with no serious effects.

Huh?... no, sorry, that statement is completely false.

Not surprizingly, "anonymous", the Venus, Earth, Mars system represents one of the multitude anthropic balance points that exist between diametrically opposing runaway tendencies that are common to the anthropic coincidences:

Venus suffers from the runaway greenhouse effect, whereas Mars represents the cold stagnate proof of what will happen if extremist environmentalists get things all their way too, so heed the lesson of this anthropic coincidence.

This is also the reason that you can't just start changing the constants around any old way that you want to, in order to make new universes that are conducive to carbon based life. It just won't work, and it has been tried, to no avail. For example:

Anonymous said...


In summary, if 1) consciousness can evolve and run in-silico (essentially naturalistic dualism, which is also necessary for a Singularity to occur) 2) the evolution of advanced intelligent beings is very rare (as this article seems to be pointing out) and 3) if, when these intelligent races evolve, they rarely but sometimes construct "ancestor" simulations using incredibly powerful computers, then the liklihood is high that we and the universe we see are actually a an "ancestor" simulation. Proving this is of course altogether different, since evidence for 1) and 3) seems pretty thin at the moment.

One possible bit of "evidence" is quantum mechanics. Recent work on Bell's therom seems to rule out "hidden" variables and indicate that, in fact, a fixed value for the state of particles really doesn't exist until it is measured. If we are running in a simulation, then the simulators may have needed to construct it in a way that conserved computer resources, so instead of tracking the state of every particle, it only probabilistically exists until we measure it.

Some other possibile consequences are that the simulation constructors might simply not want their "ancestor" experiment, namely us, to interact with another in-silico evolved species, so we are really the only intelligent species running in this simulation. Another is that the simulation may not be able to handle a post-Singularity intelligence, depending on the capacity of the computer, so the simulation constructors may shut down the simulation as we approach a Singularity-type event.

Anonymous said...

Someone said above that nature has patterns that are repeated along very different things (at least different to our eyes).
If we think of life evolution in general by looking to the evolution of a single living being, we may infer that it's something that starts simple as a child and goes on evoluting and getting complex as the time passes.
Maybe humankind is in a level of life evolution that is just no supposed to be in contact with others, maybe it's a child phase of life evolution. And life in this stage does not spawn close to each other because they are not supposed to.
Following this line of thought we may say that there are advanced life species that communicate with each other in a remote location of the universe (or maybe this happens to an infinite number of species and in an infinite number of locations), and that even if they do have the capability to visit us, they do not because they have passed through this phase of evolution and know that things should be like this.
Higher technology is the direct consequence of higher levels of consciousness.

Anonymous said...

"Absence of evidence is not evidence of absence.

Posted by Anonymous | 12:44 PM"

Yes, yes it is. Not proof, mind you, but it is evidence.

A better thing to say would have been "we haven't looked everywhere yet" or "we may not know what to look for"

Anonymous said...

We just don't know enough at this point to say. Some other possibilities:

1. Life is unstable. It may be that once you reach a certain technological point, the ways in which it's possible to wipe out your civilization grow much, much faster than the ways to avoid it.

2. The universe is a minefield. Once you reach a certain technological point, further advances run you into some quirk of physics or unknown reaction that will destroy you.

3. There are long-term events we don't understand. Maybe life in the universe gets wiped clean every four billion years or so by a process we don't yet understand, so there's never time for life to continue long enough to develop a galaxy-spanning civilization.

4. Maybe intelligent life does rapidly take over the universe once it gets to a certain point. If the time span from the start of civilization to a complete domination of the universe is only a few million years, and the rise of civilizations is rare enough that one only comes along every few hundred million years, then the odds of two galaxy-spanning cultures existing at the same time are extremely small. In other words, it could be a 'race to the finish line' with only one winner, with the odds being great that the 'winner' will be alone in the universe as an intelligent civilization.

5. It's just math. The Drake equation still has some big unknowns in it. We have a pretty good idea that microbial life should be widespread. And maybe it is. But we really don't know how likely it is at all to get from microbial life to intelligence. Maybe we were a one-in-one hundred billion shot. Maybe the real mystery isn't where everyone else is, but how we managed to beat the fantastic odds the universe put up against us.

Anonymous said...

Sample of 1.

We have a sample of 1 intelligent species capable of communication outside of their planet. We have a sample of 1 planet that we have verified holds life. We have a sample of 0 intelligences that have actually visited another solar system. What conclusions can be safely drawn from such a small sample?

That there is at least 1 intelligent species capable of communication outside of their planet (us).

More specific points:

You refer to the "Great Silence". The main problem is that even if other intelligences are presently trying to communicate with us (say, via radio waves), there's no guarantee that we would have heard them yet. We've searched a tiny percentage of stars and a moderate percentage of the electromagnetic spectrum from those stars for what we think might be communications - personally, I wouldn't expect results from SETI within centuries (quite possibly millennia), barring a sudden and dramatic increase in resources.

"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." - Assuming that there is no easy way to communicate faster than light (and note that if there is, we wouldn't be detecting such communication at the moment, anyway), 'far away' can equal 'not enough time'. In other words, if intelligences capable of communicating between galaxies are rare enough, they could presently be attempting to communicate with us, but the signals just haven't reached us yet. A similar argument can easily be made for travel/probes - sure Species Zeta may have colonized their galaxy 2 billion years ago, but it could easily be billions of years before they reach our galaxy (never mind our planet).

So put me down as a skeptic. I am glad that we're finally able to obtain reasonable estimates for N and F[p] (in Drake's equation), and perhaps a bit of a handle on n[e]. We've still got a very long way to go before getting a reasonable answer to that equation, and until we do, there's at least a possibility that Fermi's paradox doesn't apply (because interstellar-traveling life is rare enough that such civilizations haven't yet had the time to expand to or communicate with us).

Finally, there are a number of other possible flaws in Fermi's "paradox" (and its variants); the real problem being that until we encounter another such intelligence, these postulates are impossible to verify:
1) Intelligent species will tend to expand into other star systems.
2) Intelligent species will tend to expand or explore exponentially.
3) Intelligent species will tend to use probes and/or leave traces of exploration in a significant percentage of star systems.
4) Intelligent species will tend to attempt to communicate with other potential intelligent species they have never met.

In short, I view Fermi's paradox, at best as a limit to the solution for Drake's equation, and at worst as not useful.

Stephen said...

What if it's easier to fix your world than to find and go to another one?

So, as the Sun gets hotter, you put a sun shade over the Earth, at L1.

So, the Sun expands to a Red Giant, but by slinging a modest size minor planet around Jupiter and Earth, you can move Earth out of the way. When the Sun cools, move it back.

Then, Earth is a good spot to live for tens of billions of years to come.

There's no need to colonize Epsilon Eridani, so we don't.

Thirty billion years later, the Sun has cooled too much, so we move on. We find a younger star coming by, terraform some planet around it, and move there.

The Fermi Paradox is solved by laziness.

Anonymous said...

One key assumption in the Fermi paradox is "we haven't seen them". But maybe we are dismissing what we actually saw.

There are numerous UFO sightings, and even if a large number of them can be eliminated, the most serious reports generally conclude that there are a few cases that are, to put it mildly, difficult to explain. If the simplest explanation we can come up with for a given UFO sighting is: it's a technology, and it's not ours, then... maybe we actually have seen them. Such sightings are not even infrequent.

The problem is that these events are too often dismissed as "non scientific", probably because we cannot reproduce them at will. That would be much like a cow dismissing train sightings as non scientific because it can't read a time table...

Another point is that, given how difficult it is for us to communicate with biological entities that are really close (living on the same planet, sharing the same DNA), like dolphins or chimps, I suspect that communication between species is really tricky. It's probably not Star-Trek simple. We don't devote much energy ourselves to talking to chimps, do we? So why would a space faring species do more than simply study us in their own terms, yet remain unable to even notice that these SETI signals we send are actually attempts to communicate. If it takes us years to undestand how a chimp communicates with another chimp, it may take them years to understand what we are trying to do here.

As for simply landing and walking around with space suits without any possibility of saying "We come in peace"... I think even we wouldn't do something as stupid if/when we get there. So why assume they would? Why risk being shot at, or causing widespread panic, or change our culture, all these bad things? Or maybe the global warming, the shape of trees that grow, or these subtle changes in the Sun's energy patterns are their way of saying "hello, we are here" and we similarly can't notice.

So in my opinion, there are really a large number of reasons why a pattern of "occasional strange sighting, practically no communication" is more or less exactly what one should expect based on our own experience on earth with other earth-bound species.

Anonymous said...

@anonymous (4:54 pm) - "There are numerous UFO sightings, and even if a large number of them can be eliminated, the most serious reports generally conclude that there are a few cases that are, to put it mildly, difficult to explain."

"Difficult to explain" does not mean that the simplest explanation is technology guided by extraterrestrial intelligence. Lots of major UFO sightings have turned out to be military hardware (often experimental), light reflected from lasers, bad software, meteorites or atmospheric phenomenon. Occam's razor suggests to me that those causes are far more likely than something guided by extraterrestrial intelligence.

Star Larvae said...

Don't equate life with protoplasm or protoplasm + silicon.

The supersentient ETs are all around us. Just look at the night sky. They have evolved from puny chemical to mighty nuclear metabolisms. The stars themselves are the missing ETs. And we, dear friends, are part of the stellar life cycle. Excruciating detail provided at

Anonymous said...

"Difficult to explain" does not mean that the simplest explanation is technology guided by extraterrestrial intelligence. Lots of major UFO sightings have turned out to be military hardware (often experimental), light reflected from lasers, bad software, meteorites or atmospheric phenomenon. Occam's razor suggests to me that those causes are far more likely than something guided by extraterrestrial intelligence.

Serious UFO studies (as opposed to "I want to believe" kind of studies) typically reject any case that might, even with a bit of a stretch, be explained by any of the above. The CNES/GEIPAN program is a good example of such a study. I find that Occam's razor in the remaining cases simply does not lead to your conclusions at all.

If it looks mechanical, if it behaves intelligently, if it is seen by several people and machines, if multiple similar sighting are made over long periods of time (at least tens of years) and at very different locations, and if it behaves in a way that is incompatible with the state of our science, then it can't be for example military hardware (which would not have been observed in the 1880's or before), or strange meteorological phenomenas (which would probably not seem to move at high speed to ground-based radars).

Something I find particularly relevant to the present blog is that "classes" of UFOs exist. We all know of the saucer shape, but there are also cigars, etc. Usually, the behavior pattern (movement, lights, etc) is correlated with the shape. That would also be consistent with them being technology rather than transient illusions.

Anonymous said...

I agree to the fact that, at the present time, we are too arrogant to think we've not yet achieved the understanding to see the big picture more clearly. we should refer some of these questions to the buddhists, no joke intended, although they might think too little of themselves..

Drew said...

This is sort of a misuse of the paradox. It's meant to be sort of a fun speculation, not a solid claim to have a real equation that's only missing the numbers. We don't and probably cannot know some of the key components of the "true" equation, including the things like the reality of space travel (there may not really be any useful physical possibility of seriously colonizing other worlds in a useful way), or even the actual likehood of life to care about spreading (for all we know, intelligence itself could be a blip in a much larger course to something else that does not require much resources or care much about the physical universe, such as a much richer VR reality or super-intelligent bacteria that exists to think and imagine rather than move. The possibilities are endless, and we have no idea which are likely.

Anonymous said...

@anonymous (8:49 PM - please use other (as your identity), and a handle - it makes it easier to communicate).

"Serious UFO studies (as opposed to "I want to believe" kind of studies) typically reject any case that might, even with a bit of a stretch, be explained by any of the above."

Could you please point me to one that you think is serious? Frankly, the last one I looked at had as its "piece d' resistance" a movie that appeared to be a 2-stage rocket, taken well after 3-stage rockets were in use by multiple countries.

By the way, I missed weather balloons, staged fakes, airplanes, satellites, and kites :-)

...then it can't be for example military hardware (which would not have been observed in the 1880's or before)...
By the way, if you're not a military history buff, you might be very surprised with the state of the art in military technology in the 1880s. Flying objects were in common use by multiple countries at the time - observation balloons were first in military use by the late 1700s, kites (that could carry a person) were apparently in military use by the 6th century C.E.

Anonymous said...

I think you guys are still too quick to dismiss the Rare Earth Hypothesis (REH).

It appears that part of the REH seems incorrect (required steller metallicity for terrestrial planet formation and, thus, the limited galactic habitable zone). However, the most significant aspect of the REH, which is the necessity for plate tectonics and its connection to having a large moon formed by an improbable impact in order for complex life to form, remains standing in my opinion. If this turns out to be correct, then the number of complex life harboring planets in the galaxy is likely to be 10,000 to 1,000,000 time less common than is generally thought. If true, this would certainly account for the Fermi paradox.

The reason why this is relevant is because I believe that REH is correct in that plate tectonics is essential for the formation of complex life. I also think that the giant impact that created our moon is also what broke up the crust so that plate tectonics can occur. This impact also created a thinner crust (both Venus and Mars have thicker crusts than the Earth), which also allows for plate tectonics. Also, the tidal effects of the moon are what maintain plate tectonics on Earth.

This is significant because I think without plate tectonics, an Earth-like world turns into a Venus hellhole. This is because, without the moderate vulcanism that plate tectonics allows for, the internal heat energy builds up for several hundred million years and then is all released at once in a global resurfacing event. It is these global resurfacing events, as well as runaway green house effect, that makes Venus be Venus.

In other words, if this is correct, all of those Earth-like worlds yoy guys think are out there are likely to be Venus-like worlds instead. This would certainly account for the fermi paradox.

The REH could be wrong here as well. However, the instrumentation to test by identifying and characterizing Earth-like worlds in the steller neighborhood will not be available until 2020 or so.

The other useful activity would be to study Venus and figure out how it became what it is. Since it IS in our solar system, this is quite doable either.

Anonymous said...

Perhaps any sufficiently advanced civilization will simply decide to
LEAVE our universe out of desire or necessity. There are many things about our universe that would be unattractive and considerably lifestyle-crimping to any advanced hyper-intelligence with an ounce of common sense. For one thing, there's that snail like 186,000 mps speed limit, which makes it take years just to get to the next star, during which trip any machine mind with it's 10^100 flops per second would likely die of boredom. And speaking of flops per second, that C speed limit even puts a damper on things there, since you can only get a signal from one side of your nanobrain to the other so fast, making the next cranial processing upgrade a pain in the download port. Then there's all that energy that said advanced Type 9civilization and its denizens require, which is sort of hard to come by in this low energy density hyper inflated sack of hard vacuum we call home. And to make mattters worse, there are those pesky Three Laws of Thermodynamics. No friends, not even a thumb-suckingly intelligent civlization just one or two singularities under it's belt is going to hang around this dump for more than a picosecond. It's off the the universe next door where the physics is a bit more optimized, or through the wormhole to that custom built double wide dream cosmos all gussied up just the way they like it. As for us, we'd better just hope they don't decide to use this old universe for a trash recepticle or tear it down to put up the next leg of an inter-reality freeway.

Anonymous said...

The chances of two events being fairly alike in this universe are almost nil, from sub atomic level to galactic level.More complex the event, such as the existence ofintelligent being just impossible.Let us not get carried away by the vastness of the cosmos. The spacetime,as have described in the Mest TOE, is not something external to the matter.It doesn,t require only unique combination of mass and energy but also the unique spacetime for the creation of a complex intelligent life. The idea of ETI is therefore nothing but figment of imagination.
Babu Gautam

Anonymous said...

Until we quit trying to listen to digital HD-Radio with the high-tech equivalent of a AM crystal set we're really not going to get anywhere. If radio based SETI is going to work, they'll need to devise a method for "digital carrier detection with unknown protocol" and do some research into being able to effectively find and identify digital signals in the first place.

But then again there might be a conflict of interest with current powers-that-be in being able to do what's really necessary to find ETI. If you could effectively detect digital communications, the subseqent ability to analyze (and possibly decrypt) them would be of great military/commercial intelligence value. There isn't a lockout on this area of research is there?

Then of course there's always the other situation that I suspect: Life (bacteria and the like)is probably abundant in the universe, but evolved intelligent life (and that which has developed technology) is probably on the sparse side.

Robert Smith said...

There is another possibility that no one has mentioned. It won't be very popular, though I think it is no more speculative than any other idea posted here. And it does have the advantage(?) of being accepted by a very large percentage of humans throughout history.

There are non-human sentient beings. They are in constant contact with us, in fact different parties among them are in a war over our ultimate destiny. But their "physical" existence is based on modes entirely outside of our current knowledge, hence their existence and attributes are currently entirely outside the realm of science.

They are/were known to most of humanity as angels and demons. Hence we are a "managed" species. And if there are any other "others" we are being kept away from them.

Read C.S. Lewis's space trilogy (Out of the Silent Planet, Perelandra, That Hideous Strength) for a fictional treatment. Try the preface to "God at War" by Greg Boyd for a theological, sociological treatment.

So, what about it? How would your universe look if you wanted it to look like an artificial creation to planet bound creatures?

I believe that both DNA and the universe as a whole are signs of extra-terrestrial intelligence. Now, how can you contact an intelligence that exists outside of the universe?

Posted by asahel

You don't. He/It contacts you.
"In the beginning God created ..."

Anonymous said...

Everyone seems to forget the Moon. Earth has a very large companion world and there is some evidence that points to a large companion world being a requirement for a stable atmosphere. Mars is not that different from Earth, yet any water cycles it may have/had seem on too short a time frame for the development of complex life. Furthermore, we have seen NO worlds anywhere that have such a large satalite. If large scale complex life is dependant on the stability that our large moon provides then lifeforms higher than the single-cell may never have time to develop. Intelligent life maybe vanishingly unlikely.

Anonymous said...

I didn't read all the other comments, so I'm sorry if I'm just repeating someone else's words.

Anyway, at one point in my life I thought the basically life sucks. I contemplated about what humanity would look like after technological singularity. I suppose by then you'd be able to create any kinds of living or at least conscious things that you want. You might also assume that they are given the capability to edit their own emotions (or whatever). So, suppose there is some day a superintelligent AI that doesn't have an instinctive drive to live and reproduce, why would it bother to exist at all?

What if the fate of every advanced civilization is destruction by one of two means: they obliterate themselves with supernukes or such, or they develop themselves into superintelligent beings that realize it's not actually that wonderful to be alive and decide to shut themselves down.

I suppose that could explain why we don't see intelligent life elsewhere in the universe. There may have existed several advanced civilizations, but maybe the got to modifying their emotional reactions (or maybe removing them altogether) and what they got was superrational beings. And these beings - not fearing death - disabled themselves.

It's also possible that these superintelligent beings thought curiosity about your surroundings isn't that great... That they decided to just stick to their home planet.

So... supposing that most civilizations reach technological singularity before discovering interstellar travel, what would these superintelligent creatures want? What would be their motives? Would they bother to explore the universe and would they even bother to exist?

Anonymous said...

I read that Fermi came up with his paradox equation over lunch, casually. If that's so, then he did it in less time than it's taken me to read through all these fascinating posts.

In other words, even though its been elaborated later, the so-called paradox itself has an inbuilt flaw - not half enough time was given to thinking through the variables and mitigating factors. We may be chasing our tails here (highly stimulating though that is!) trying to solve a paradox that is essentially only a semantic riddle or lunchbreak musing.

I suspect we're all still thinking within the box here - even though there are some thoughtful attempts to climb out. We are maybe - per Einstein's observation - trying to solve a problem at the level at which it is experienced, with the same tools that created it.

Maybe we are not wired to be able to think outside these bounds - who can truly imagine 10 dimensions of string theory? What if intelligent life is indeed absolutely teeming all around us in those dimensions? I could, I suppose, build an argument for that along the lines of 'nature never wastes anything': why would 'nature' waste all those vast tracts of space and all those billions of stars etc...? Perhaps all those stars are there for completely other reasons than we are able to imagine...? I don't know...maybe they generate the right quality of quantum fluctuations to sustain the right vibrations for all those strings...maybe they produce the right flavour of neutrinos to shoot off all over the universe and give just the right background hum for strings...?

Maybe it only looks to us that the universe is perfectly tuned for our evolution because we can't imagine that it's actually infinitely better tuned for intelligences that exist in higher dimensions?

Maybe humans or any intelligent life in 4 dimensions are simply a total aberration, a rare by-product - like 6 digits instead of 5 - when, in fact, the real party's in full swing amongst the strings....?

Anonymous said...

I think that any possible earlier technological ET civilizations would become more efficient at using energy as they gained more knowledge of physics.
I also think that their efficiency with energy would make them subtle by nature, and not easily detected.
They could already be here in your bloodstream or in your brain, their mega society might have colonized all of humanity and all the biosphere but we might be too technologically primitive to detect them.
Either that or the prime real estate for profligate energy wasters is nearer the galactic core!

Anonymous said...

Hi, just a passer-by here. Though I've not read much about the simulation theory, as I currently understand it I have to object to it on moral grounds. How could a race seek to recreate all the suffering in its history?

giordano bruno said...

I doubt that fleshy water diffusion intelligence would travel. Even with the atmosphere-equivalent of 10 metres of ice shielding, the time-to-decay of secondaries would fry them.
ie you need that 10km of atmosphere to allow secondaries time to decay.
So that leaves solid-state, ie built, not grown intelligences.
Problem here is robot-drug-addiction. Lets say the robot has a "Travel is Good" register which keeps it on it's merry way. Because it has its own schematic, it knows the location of the "Travel-Dispersion = pleasure" register,, so it simply sets it to "Full = happy" and ceases to travel. Humans dont have schematics (yet) so crude Morphine loading isn't fully satisfying (ie. its boring, we need to find the "bored" register/accumulater and set it to "empty"? As Burroughs said, junkies are not interesting/interested, they sit around staring at their toes all day), and the rulers tend to throw you in prison if you use morphine every day.
How to keep that robot traveller travelling? Wetlife loves dispersion second only to reproduction, but its just an urge/itch, which solidlife will always (?) override?

Anonymous said...

Isn't colonization (of the galaxy) a 19th century concept? Society is struggling to find its way towards living in balance with its environment, in a sustainable way. If we achieve this, what need is there for constant expansion? Isn't it being rather immature to always want more? So maybe ET societies just settle into comfortable middle age - of course, all it takes is one exception to the rule...

I agree that we simply don't have enough information to make even an educated guess at this time. It is interesting to note however, that in choosing a random point in the history of life on earth one is unlikely to see technological intelligence, so I suspect that intelligent life is exceedingly rare, and given our current problems, probably short lived.

I think it is hubris to state that the universe is "designed" to make the emergence of life inevitable. It is in fact extremely toxic to life - try living outside our thin strip of atmosphere! Even if certain cosmological values seem "fine-tuned", is this any different to an ant claiming that because the cracks in the pavement provide it with a benevolent environment, then the whole city must have been built to this end!

Anonymous said...

My little idea is somewhat similar to Talin's post (inward expansion of technological civilisations prevails over outward expansion).

It is that the total 'space' (of whatever type, virtual or physical) that is easily accessible for colonisation vastly exceeds the known universe. The probability of any two civilisations meeting in this larger space - which includes the known universe - is therefore *extremely* low.

A key factor in my reasoning is that such space is energetically and practically very easy to reach by beings only slightly more advanced than Homo Sapiens.

Anonymous said...

Maybe the civilizations that beamed radio signals out into space attracted attention and were wiped out...

Anonymous said...

Great topic and some really interesting posts here. I would like to add one, which is based on assumptions.

The Fermi paradox is based on many assumptons. One of them is that Evolution will breed intelligence, and intelligence is a higher order of life. And we offcourse are intelligent.

We are mortals. We have memories incapable of remembering a simple ten digit number without considerable effort. We think of ourselves as within our minds beeing like gods. According to Freud we are sex crazed paranoid schizofrenic and above all very influancable cyclebased nutcases. Sleep and death are all that keep us sane. (Sane as in our definition of it) Real intelligence surely would not bother to stay alive?

Anonymous said...

I've solved it. Any alien species that cannot travel through space isn't intelligent enough to do so. Any alien species that can is intelligent enough to not make contact with humans.

Anonymous said...

I have yet to see any "learned" reference to the fact that planets and systems rotate at different speeds in varying planes and angles, sometimetimes with complex motion. This, and obscuring bodies/intersellar crap all conspire to make point to point communication extremely tricky even if two distant civilisations knew where to aim. Add another factor (Alignment) of < 0.0001 to Drakes equation

Andy R

Anonymous said...

Seems like Fermi Estimations can only be as relevant and accurate as the assumptions they are based on. One could surmise the underlying assumptions we have about intelligent life and/or the universe are not complete enough to form the basis for performing this sort of analysis.

Anonymous said...

The resolution of Fermi's Paradox is easy. Random evolution of sentient life is so rare that most galaxies never have any sentient life, and very few galaxies ever have 2. Humans are the only sentient life in the Milky Way and that will probably be true for billions of years.

Mosts atheists would say that lack of evidence is more than enough proof that God doesn't exist. Using the same criteria there are no other intelligent species in our galaxy.

Anonymous said...

don't you know that the fuel for these "random" reactions are in most if not all newly formed solar systems try

Anonymous said...

juhazone you wrote:

"So... supposing that most civilizations reach technological singularity before discovering interstellar travel, what would these superintelligent creatures want? What would be their motives? Would they bother to explore the universe and would they even bother to exist?"

I think this is an important point. If we assume there have been many civilizations in our galaxy to reach at least our level of technology, some universal killer must have stopped them from colonizing the galaxy.

It's reasonable to assume that artificial intelligence is necessary for interstellar travel. So that could be it.

What I find very frightening with the Great Silence is this: If we humans had the technology today to travel and colonize the galaxy, would we do it ? I'm very sure we would. It's human nature to explore the unknown, take risks.

But no Aliens have done it, so they must be very different from humans. Furthermore, our chances of surviving as humans and colonizing the galaxy are slim, since no creatures with the same urge to explore have done it in the history of the galaxy.

Will the human way of living and thinking be killed off by AI ?

I have been looking for people with the same interests as me, so we could exchange ideas etc. The subjects would be The Fermi paradox and the technological singularity. Maybe we could create a forum for discussions ?
Please contact me at

Martin Andersen

Martin Andersen said...

I have created a forum where we can discuss the Fermi paradox and related topics. I hope to see you at:

Anonymous said...

Please, do not see this as a naive comment.

What if the advanced civilizations would find a better return on investment on creating virtual realities in which to download and live? As you can see in our world, it doesn't happen at all that decisions are taken thousands years in advance, and the temporal horizon for decisions is sometimes barely the length of an administration. I.e. we all tend to decide for *now*, because that's what makes "economic" sense (in the broader sense).

So, would you spend your life traveling between stars constrained by speed or light, or would you prefer to spend your life inside a virtual world designed to satisfy your needs?

Maybe the civilization expansion is not toward outside, buy toward inside.....

Falkor said...

the secret is they are hiding in the fifth dimension.

Ooops! sorry..

Anonymous said...

What if we are being watched, but the observers don't want us to know yet? They could be watching, waiting to see if making contact with us is desirable. Would you want to interact with us if you were an alien? We still fight among ourselves over skin color, gender, and cultural differences; how would we treat visitors from another planet?

Anonymous said...

"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.".....

Could well be the truth :O( !

Anonymous said...

The Drake equation has many factors missing that would reduce the numbers dramatically that communication might be established between aliens.
For one, is the problem of the relative angular planes of rotation of systems/planets. This means the chance of observing communication from the surface of a planet is dramatically low.
Also the probablity of the existence of compatible communication technology existing simulatneously in a given time frame.

Xtraeme said...

In response to Zimbel & Mr. Anonymous,

When discussing Fermi's paradox I'm often reminded of the quote, "Water, Water Everywhere But Not a Drop To Drink" or more appropriately in this case "... Not a Drop To Prove it."

The concept of UFO is broad, incorporating misidentifications, psychological components, possibly new atmospheric phenomena, and who knows what else. The argument that all UFOs represent misidentifications is a fallacy dispelled by USAF Blue Book Special Report 14.

It's fair to say that in some instances UFOs may in fact be non-human technological devices. Probably the best empirical evidence of this to date comes in the form of the 1957 RB-47 case analyzed by Brad Sparks. It's by no means a short read, but it does demonstrate something of a fairly extraordinary nature. I find it difficult to imagine a natural explanation for a radar-emitting ball of light that has the ability to pace a RB-47 and follow it across several states especially during course corrections.

This case stands out because it's tightly corroborated by verification from several passive radar sets, active radar detection on the ground, and mid-air /w visual observations. It's hard to imagine such a thing being an atmospheric or astronomical phenomenon.

It's amusing to think we're very likely ignoring evidence that might explain Fermi's paradox ("Where are they?" the answer being "Here") simply due to dogma and our inability to accept anecdotal / transient evidence.

pauljs75 said...

Here's are the ways I look at it, but these are already known variations of the Fermi Paradox.

1. Life is pervasive, but evolutionary fitness does not ensure the development of intelligence. For example, most living things on this planet are either microbes or insects. Or even going into higher species such as vertebrates, look at the good run the dinosaurs had. But what did they make of it?

So we're not alone in the universe, nor the galaxy. But we're not going to communicating anytime soon to critters not much smarter than the average house-cat.

2. Intelligence actually does develop, but conditions for technology to develop are much much rarer. In other words, we're the only kid in the neighborhood to have toys. On this planet, there are a few other animals besides the dominant hominid and the apes that would qualify as being higher-up on the earth-critter IQ chart. Look at the whales/dolphins/porpoises or even parrots for instance. However, they lack the physiology to manipulate their environment in any significant manner. Or take a look back at our own history. How long ago was the bronze age or the iron one? In terms of life on the planet, that's actually a pretty short while back. Also, where would we be if there wasn't much in the way of friable mineral resources? We'd probably still be rubbing two sticks together to make fire and talking about the upcoming hunt rather than reading this internet post exploring mundane ideas.

3. There are actually many other beings zipping around with all the sci-fi like technology and beyond, but we're intentionally kept out of the loop. This one's known as the Zoo-Hypothesis. And we're the monkeys in the zoo. In a way, this scenario would give some credibility to the UFO, alien sightings, and abduction phonemena. If they're here, they're only only doing observations and otherwise staying out of the way. Until we can get out of "the cage" in any meaningful manner, we're not really a problem nor worth communicating with. Of course a few animals in the zoo (including us) will experience the occasional veterinary services related to park management. The abductions are merely part of the health and fitness surveys, and the implants are equal to tag-and-release programs. (Not necessarily pleasant on the recieving end, but well intentioned otherwise.) Afterall, if our solar system is a "zoo", somebody has got to do the part of the park ranger or wildlife researcher.

I'd say 1 and 2 are likely enough because of the general chemistry that exists out there. Life should pop up somewhere else. It would be fun to know how many smart things are running around out there, but it's not like we can go to them anytime soon.

Number 3 seems unlikely, but is fun to consider. Yet if it's true, we won't be hearing anything until we figure out how to poke around and get outside our own solar system. When the caretakers are spotted or communicated with before then, it's not by protocol and something that they try to avoid. Pretty much they're not wanting to rattle the cage and having all the monkeys go ape****, if you know what I mean.

I'd rule out the hostile or other theories, simply because we're in existance and there isn't much to say anything has visited or communicated with us in a significant way.

Anonymous said...

i have heard of extra dimensional as well as extra dimensional intelligences visiting many people before. also read that comment about multiple radars tracking a ufo. what about the abduction stories, i mean there must be some truth to it. i doubt it is the result of a disinfo campaign. greys, nordics, mantis, reptilians, etc. are types of aliens that have been reported.

what is going on is a multi level cover up. part of the cover up is coming from human governmental activity and the rest of the cover up is from the extra dimensional entities. perhaps we are not recieving any radio transmissions and not seeing any activity in space because its all being censored by some type of quantum technology. the Fermi Paradox is very short sighted and to hold dear to it is foolish. this is one of those scenarios where you have to go with your gut. you do not always need direct proof. indirect proof can be enough.

so that is what is wrong with our thinking. we have to balance out the purely scientific mind and approach to life with more right brain flow. if we do not then we will never understand what is really going on.

Patrick D said...

hello friend excellent post about The Fermi Paradox: Back with a vengeance, 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 and I would like to know if you have any post about buy generic cialis
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.

kins80 said...

I tend to think the breakdown in Drake's equation is that there is no distinction between complex life and intelligent life. I believe that life, and even complex life, is common throughout the galaxy and universe. However, for life to evolve to the point of self-awareness, scietific endevor, etc may be .001% or less for all we know. Why was it evolutionarily neccasary for humans to be scientifcally curious? I don't have a good answer for that. If anything, my guess is that it would have slowed them down in the hunter-gather sense. If we chalk up the human race to an evolutionary "blip" that is outside of the norm for the rest of the galaxy, combined with all the other reasons stated (distance, time, etc) I don't think there is much of a paradox.

Anonymous said...

are humans continuing to evolve? with all the technology we have more and more diseases, disasters, etc are survivable, slowing down natural selection, maybe due to such advances humans have ceased further evolution, more people that would likely not survive life in primitive times are alive and instead of evolving to a further level our species stagnates and doesn't get any further than early man. there are few differences between modern humans and humans from lets say 2000 b.c. we are taller in stature and our brain has increased in size. our intelligence may actually be all that is changing

God Of Google said...

Interesting... the whole idea of energy and other galaxies is fascinating to me... thanks.

pfh said...

I agree with the comments above that a question is raised by what we see humans doing with "intelligence".

Humans have been using their powers to increase their powers to the point of collapsing their environments. That's been happening at large and small scales very repeatedly without our "intelligence" being able to grasp the question posed by it.

The inverse is also common, though, making the question much more interesting to investigate. That line of thinking comes from new directions being taken in the study of self-organization, considering change in physical systems as a construction process.

As regards Fermi's Paradox, change as construction also seems consistent with Elsasser's view that "persistent heterogeneity" in nature is inconsistent with the universe being a stochastic process, and far more improbable than universe could produce. He thought it would mean life and every other persistent form we find needed to be the product of something else.

micheal said...

I believe the reason we have not made contact is simple...First we must learn to get along with each other on this planet! And when we do then we will be ready to meet our neighbors. Peace Out!

Anonymous said...

Lets look at the reason we have yet to meet ET. We function in a less than whole universe defined by our maths. Lets call that Universe 'A', so over there in 'NOT A' separated from us by a 'string' is an alternate mathematical rule set that we are separated from. Now at Superposition A and NOT A are the same thing and if we were at Superposition we might perceive the 'alien' or perhaps we wouldn't because at superposition we would be both A and NOT A because we would be both us and them.
So right there we have a problem.

There could well be Life - but in the end we are incapable of perceiving it in either state because they are in their own pocket reality and we could only be at superposition so the 'Alien' nature of our relationship vanishes instantly. At superposition they are us and we are them.

If Life is a Superpositional Organism then the Theory of Evolution falls down. Basically Charles Darwin becomes a prat who made others look stupid because they believed him - scorned religion - and ran off and married his sexy cousin; and My Superpositional theory of Life can be scrawled inside the front cover of any textbook along with a smiley face and the words 'denied the Nobel prize by stupid people who are busy having sex with themselves - because that's what it looks like from Superposition'.

david said...

Analyzing the possible evolutionary patterns of species completely unknown to us is trivial and assuming too much. Life in other parts of the universe would most likely not evolve similarly to us. Their method of species of evolution would most likely be completely alien and probably would not be reliant on a system of chromosomes and genes as life on earth is. Life on another world could easily have evolved under completely alien circumstances where concepts such as Darwin's theory of evolution would not be applicable. These other intelligent lifeforms could have some system of reproduction and evolution completely alien and unimaginable to us. As such we, limited to our terrestrial perspective on evolution, can not begin to even guess as to how another species might have evolved.

Unknown said...

Fascinating article and thread.
There are a few comments that raise this argument, sorry if I'm repeating:
Life evolved through natural selection, we should have all read "The Selfish Gene" by Dawkins. Life, by definition, has narrow "self-interest" and evolution has no foresight. This fact explains why we can't seem to solve our immediate, pressing environmental and resource problems. Everyone is working for their own short-term interests and that of their clan, kin or nation. Our technology has had a massive 200 year "sugar high" from fossil energy and the party is nearly over. Now competition for resources will get ugly.
What if this was an evolutionary constant? Like a bacteria population colonizing the entire surface of an agar plate and then suffering collapse, each individual bacteria acts in it's own self interest and consumes as much as it can. Until there is nothing left but toxic waste.
Technology only hastens this process, allowing us to exploit the limited resources at an exponential rate. What if this is true of all life, anywhere? Life has to be programmed to seek its own short term interests and beat the competition, if it is not it is extinguished by the competition.
Life may be common, we may find it close by. But once it gets too good at exploiting its environment the algorithm at the centre of it's programming leads to it's demise?
I know that sounds fatalistic and I want to believe there is a way through this barrier. What I do know is that the best chance we have of solving a problem is to fully understand it. So I'd prefer to confront it for what it is.
Comments and refutations very welcome..!