How the 'Great Filter' could affect tech advances in space

May 14, 2014 by Elizabeth Howell, Universe Today
Kepler-62f, an exoplanet that is about 40% larger than Earth. It’s located about 1,200 light-years from our solar system in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech

"One of the main things we're focused on is the notion of existential risk, getting a sense of what the probability of human extinction is," said Andrew Snyder-Beattie, who recently wrote a piece on the "Great Filter" for Ars Technica.

As Snyder-Beattie explained in the article, the "Great Filter" is a response to the question of why we can't see any alien . The "Great Filter" deals with similar issues as the Drake Equation, which talks about the probability of communicating civilizations outside of Earth, and the Fermi Paradox, which asks where the civilizations are.

Simply speaking, the idea is that if a civilization continues to expand (especially at the technological pace we humans have experienced), it wouldn't take all that long in the lifespan of the universe for artificial processes to be visible with our own telescopes. Yes, this is even taking into account a presumed speed limit of no more than the speed of light. So something could be preventing these civilizations from showing up. That's an important part of the Great Filter, but more details about it are below.

Here are a few possibilities for why the filter exists, both from Snyder-Beattie and from the person who first named the Great Filter, Robin Hanson, in 1996.

'Rare Earth' hypothesis

Maybe Earth is alone in the universe. While some might assume life must be relatively common since it arose here, Snyder-Beattie points to observation selection effects as complicating this analysis. With a sample size of one (only ourselves as the observers), it is hard to determine the probability of life arising – we could very well be alone. By one token, that's a "comforting" thought, he added, because it could mean there is no single catastrophic event that befalls all civilizations.

Advanced civilizations are hard to get

Hanson doesn't believe that one. One step would be going from modestly intelligent mammals to human-like abilities, and another would be the step from human-like abilities to advanced civilizations. It only took a few million years to go from modestly intelligent animals to humans. "If you killed all humans on Earth, but you left life on Earth—and the animals have big brains—it wouldn't necessarily be that long before it came back again." Some of the filter steps leading up to that would have taken longer, though, including the emergence of multicellular animals and the emergence of brains, roughly on the timespan of a billion years each per stage.

How the ‘Great Filter’ could affect tech advances in space
Artists impression of an asteroid flying by Earth. Credit: NASA

'The Berserker Scenario'

In this scenario, powerful aliens sit hiding in wait to destroy any visible intelligence that appears. Hanson doesn't believe that would work because if there were multiple berserker species, there would be opposing parties. "As an equilibrium, you'd have these competing teams of these berserkers all trying to smash each other."

Maybe natural activities are masking the extraterrestrials

Maybe the big natural activities of those beyond Earth just happens to look exactly as if they are not there. Hanson said it seems rather unlikely, as it would be a "remarkable coincidence" if advanced artificial processes were actually responsible for all the astronomical phenomena we do explain from natural occurrences, from pulsars to dark matter.

A natural disaster

There certainly is an inherent risk to just being an Earthling. One asteroid strike, a stream of radiation from a nearby supernova, or a large enough volcano could end civilization as we know it—and possibly much of life itself. "But the consensus is we have a track record of surviving these things. But it's unlikely that all life would be destroyed forever. "If those humans who were left, it took them 10,000 years to come back to civilization, that's hardly a blink of an eye, that doesn't do it," Hanson said. The next is that statistically speaking, although these events happen, they don't happen often. "It is unlikely one of these very rare events would happen in the next century or 300 years," Snyder-Beattie said.

Artist’s conception of a gamma-ray pulsar. Gamma rays are shown in purple, and radio radiation in green. Credit: NASA/Fermi/Cruz de Wilde

A 'fundamental technology' that ends civilization

This is open to complete speculation. For example, climate change could be the catalyst, although it would seem extraordinary for all civilizations to encounter such similar political failures, Snyder-Beattie said. More generalized possibilities could be the rise of machine intelligence or distributed biotechnology, a force that is self-replicated. Hanson, however, points out that even that has its limitations—presumably then it would be the robots that head out through the cosmos and leave traces of civilization themselves.

The solution

For the fate of our own civilization, the key is to focus on what we can control, Hanson says. This means drawing up a list of the things that could kill us—however theoretical—and then work on ways of addressing those.

The question of why other civilizations are not visible still persists, however. What are your thoughts about the Great Filter? Let us know in the comments.

Explore further: From human extinction to super intelligence, two futurists explain

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dramamoose
5 / 5 (1) May 14, 2014
I think this a fantastic question. I think there's one option that isn't talked about here which might be very possible: they're hiding from us. Not saying they're amongst us and hiding, but that almost in a Star Trek like manner, they choose to maks their presence from us until we reach a certain technological level at which point we are apt to find them anyway.

I remember reading somewhere that it would be very difficult to pick something up via SETI, unless they were broadcasting it directly at us. Furthermore, possible advanced intersteller communications methods, maybe working on some quantum entanglement/tunnelling principle, might not be something we can detect.

If all of that is true, and if there is some sort of intergalactic agreement to not pester undeveloped planets, it could be very possible our lack of detection isn't due to a great filter on advanced civilizations, but rather a great filter they established themselves; one might call it a sort of 'prime directive'.
adave
5 / 5 (1) May 14, 2014
Our behavior has changed to highly inventive only in the last 6 to 10 thousand years. The needs of the individual were met completely before 10,000 years ago. Then we began to invent everything we have now in 2x10-3 of the 2.5 million years of our form. World destiny changing technology in 4x10-5 (.004%) in the past 100 years. That is a filter. War is part of our primate behavior. Destruction of civilization by invented weapons is something that is made important enough to do by our unique mix of emotions. Our only breatheable air is within 3.17 miles (highest city) or less of the surface. Altitude sickness can occur at less than a mile. Our existence is precarious. Modern behavior shows that we prefer fantasy worlds to the real unlimited universe. The real filter could be the dissappearance of Boltzmann's brains or Boltzmann like life into illusion. Then you must wait for another creature to develop hands, stone tools and fire before they walk again among the deep truths of reality.
supamark23
3 / 5 (4) May 14, 2014
It seems the actual reason we haven't heard from other tech advanced species is both distance and time - they'd likely be 100+ light years away (so no detection yet due to distance if we're concurrent) and the timing would also be an issue (perhaps they lived a million years ago, and have since died out and all their EM radiation has already passed us). Or, there's only a few in any given galaxy at any time posing both time and distance issues.
TheGhostofOtto1923
2.3 / 5 (6) May 14, 2014
There are post-organic machine singularities out there and they are talking to each other but they have absolutely nothing to talk to us about. In perhaps 10,000 years we will have been superseded as well.

These singularities also have no reason to expand or to go anywhere unless they are under threat where they are. They are also very thrifty with resource use and energy expenditure, with plans spanning millions of years.

And so we shouldn't expect to see any evidence of them or to hear from them.

Sorry but it is clear that any naturally-evolving intelligence will reach the point where it is able to design intelligence from scratch which is far superior to itself, and which can then self-improve without limit.

And then this natural intelligence will have no choice but to do so. And then it will be replaced.
Realist99
1 / 5 (3) May 14, 2014
If you go through these possibilities, the only one that really makes a lot of sense (at least to me) is the first one - intelligent life is rare. This is a good thing, it means there is a whole galaxy out there just waiting for us to expand into it.
TheGhostofOtto1923
2.8 / 5 (8) May 14, 2014
If you go through these possibilities, the only one that really makes a lot of sense (at least to me) is the first one - intelligent life is rare. This is a good thing, it means there is a whole galaxy out there just waiting for us to expand into it.
No, the only one that makes sense is that organic sentience is a very brief transition state. The machine singularities which follow have absolutely nothing to gain from trying to communicate with organics.

And since these machines expect to live forever, they would be patient enough to wait until ours emerged now wouldn't they?
marraco
2.3 / 5 (3) May 14, 2014
Is very reasonable to suppose that we are nothing special. The necessary conclusion is that our galaxy should be full of civilizations millions of years older –and more advanced- than us.

We on earth are 7 billion individuals. Each one with different motivations, and many with wildly crazy motivations. Intelligent beings don't need rational justifications to behave in crazy ways. To suicide, to kill everybody on a mall, to make art, to believe in religion, to hear music.
Advanced civilizations necessarily have orders of magnitude larger number of groups and subgroups with any crazy motivation to do anything. Even crazier than what we can imagine.

It makes nonsense to assume that aliens will do or not do anything for reasons that we choose. Billions of individuals and groups of them, belonging to billions of species and groups, will do anything possible even if it makes or doesn't make sense.

¿Is possible that one individual or group will do something with galactic effects?
We already have enough technology to spread machines all around the galaxy. It would take all of our economy, and will make no sense, from an economic viewpoint.

But what if each human had the resources of our entire civilization? Someone will send the machines.
We are 7 billion humans. How long it would take to grow our economy until each human has the resources or our entire present civilization?
At 1% grow each year, it would take 2083 years. So, in 2000 years, any human would be able to colonize the galaxy at will. No need for a rational justification. Just because is cool, or to see what it does.

If we are nothing special, which is a very reasonable conjecture, the galaxy has billions of species with billions on individuals each one, with resources and motivations to send at least machines all across the galaxy.

Another very reasonable conjecture is that some species, or some subset of them is willing to start wars. If we are nothing special, evolution, which selects for competition, created billions of competitive species. Even peaceful herbivores fight for resources. Fight is very natural, and no matter what arguments are against intelligent hostility, millions of species and groups will start wars.

The other species have 3 choices:
1- Die.
2- Fight.
3- Escape or hide.

Escape or hide must be an excellent strategy. Some species may fail, but some should have success. By avoiding battle, they avoid the grind of war. Avoiding wear and attrition is an excellent strategy. Let the fighters do the work for you.

Necessarily, some species choose to hide, for reasonable, or unreasonable reasons.

Where to hide? Stars are bad choice. They will obviously be checked by warrior-like species. Anything that can be detected is a bad choice. Nebula are bad choice. Black holes are bad choice.
So the best bet is the interstellar/intergalactic space. It is full of resources. An advanced civilization only needs hydrogen. By using fusion, it can be converted to energy, and any matter. Space is full of cold hydrogen. Nobody owns it. It is abundant. There is enough to create entire galaxies.

So, interstellar and intergalactic space must be full of advanced species. They avoid conflict. Just hide and grow.
We already hide from radar for bellicose purposes. How far can be pushed stealth technology, by a civilization with unlimited resources and millions of years of technology?
Maybe they can hide from any means of detection which do not violates fundamental laws of physics.

Maybe gravity is the only thing that they can't hide. Large accumulations of mass are detectable. They cause effects like deviations on stars, lens effects, etc.
So, to hide efficiently, a civilization needs to spread itself, and avoid clumps of mass.

The effect would be that most mass on the universe would be undetectable, evenly spread across space. That looks suspiciously like dark matter.
Caliban
3.7 / 5 (3) May 14, 2014
Hahahahahaha!

And, of course, it is still impossible to rule out that we haven't already been "contacted" by at least one such interstellar/intergalactic civilization.

Homo Sapiens, itself, may be an artifact of that contact. Or not.

But, as I said, the possibility cannot be ruled out.

Additionally, if you make the assumption that there can be no FTL travel or communication, then this automatically constrains so much of what is possible, that the lack of currently recogniseable InterStellar/Galactic SuperFrenz is IN NO WAY surprising.

This whole "Great Filter" concept is just too limited in scope to have more than partial meaning or limited bearing upon the question, and is, finally, just Hanson's failed attempt at a Digital Era "reimagining" (pretentious buzzspeak for) the Drake Equation.

If, on the other hand, they have discovered modes of travel which circumvent or exceed the S.O.L., then they could be literally anywhere and everywhere, here and now, even as we speak.

rwinners
4.2 / 5 (5) May 14, 2014
Well geez... we haven't been looking into the vastness of the visible universe for very long... in space/time. Let's give it a few hundreds of thousands of years... or so.
Silent
3.4 / 5 (5) May 14, 2014
I'd flip the question around: why would there be contact?

We don't know our future limits, but from what we do know there's no reason for any intelligence to contact us, intentional or otherwise. We assume once one understands everything at a fundamental level there's any need for physical exploration; as if immortality towards natural forces requires more than a very small number of locales; as if in our future we'd choose to keep this human condition; as if we presently understand the nature of reality; as if creation is some past event in which we, and by extension all, play no role.

To ask "why do we seem alone?" is a youthful question.
Grallen
3.7 / 5 (3) May 15, 2014
Maybe we were contacted in the past. The perpetrators were severely punished, and now conservationists guard us from the outside zealously. :p
antialias_physorg
5 / 5 (3) May 15, 2014
it wouldn't take all that long in the lifespan of the universe for artificial processes to be visible with our own telescopes.

I don't really get this argument. Artificial processes would only be obvious if they produce waste (radiation). Given that technology moves to ever better efficiency I would assume that once a species has serious spacefaring capabilities their waste would be (near) zero. They could be most everywhere but would be completely undetectable by us.

I always find these thought experiments where someone posits huge advances in X (spacefaring ability) but utter stagnation in Y (efficiency, miniaturisation, etc. ) unsatisfying as arguments.

If you killed all humans on Earth, but you left life on Earth—and the animals have big brains—it wouldn't necessarily be that long before it came back again

In the age of dinosaurs intelligence stagnated for millions of years - and might have indefinitely so if not for a big impact.
Torbjorn_Larsson_OM
5 / 5 (3) May 15, 2014
The Fermi question ("Fermi Paradox") is not sufficiently constrained, because we don't know the likelihood for false negatives.

- In fact, the simplest pathway for colonization moves people out into the system and eventually the Oort belt, where resources are sufficient and cheap. Such civilizations go EM silent as they expand and disperse, as the biospheres and their cultures will diverge in traits as they go. ("Dispersal in real space means dispersal in trait space." =D)

- Analogously "Rare Earth" is an open-ended not sufficiently constrained bayesian model, where you can derive any likelihood you wish, while only having the ability to reject individual constraints. (E.g. all the initial constraints such as "need a large moon" has been rejected by now.)
Torbjorn_Larsson_OM
5 / 5 (3) May 15, 2014
[ctd]

- And so on. The remaining steps are fairly easy vs fairly hard. Multicellularity is easy (seen many times), complex multicellularity hard (once, and late), language capable intelligence is hard (one, and late). Biologists think the latter is as the elephant trunk, evolves once in a blue moon.

So I'll mostly agree with Caliban and antialias here.

Nitpick: With a sample size of one, it can still be very easy to test the statistical process against the one sample (observability), if it is a fast process so we can test for its rapidity. And it was. Meaning > 95 % of geothermal active habitables will have life after ~ 7 billion years at the latest. (Seems to go much faster on the order of 0.1 billion years though.)
Torbjorn_Larsson_OM
5 / 5 (2) May 15, 2014
@dramamoose: As you can understand, my opinion based on its current testability is that it is an awful question. We can (should) still look for positives, of course.

@adave: Obviously our world is incompatible with a great likelihood for Boltzmann Brains.

@TGO: It isn't easy to evolve language capable intelligence, whether on electrochemical or electromechanical template. Whether the latter would "superseede" biospheres with electrospheres is an open question. The latter would be as open in likelihood for false positives on the Fermi question as biospheres.

@marraco. I think your comment, besides TL;DR, becomes too hard to follow (swallow) after the claim that all individuals would have resources on the order of the planetary production. =D
TheGhostofOtto1923
1 / 5 (2) May 15, 2014
would only be obvious if they produce waste (radiation)
And indeed this may be the only thing we could detect.

" Freeman Dyson's original articulation of this principle remains the simplest: search for the energy that a civilisation has used for its own purposes... conservation of energy says that on the whole, an alien civilisation that has a very large energy supply must expel as much energy as it collects or generates, and the second law of thermodynamics says that this expelled energy will have high entropy (very little free energy). We call this high-entropy expelled energy "waste heat", even if the alien civilisations that uses it is very efficient and not at all "wasteful". In fact, the more efficient the civilisation is, the higher the entropy of the expelled energy, and the more it will have the properties of the sort we expect to see from waste heat."
TheGhostofOtto1923
2.8 / 5 (5) May 15, 2014
"you'd have these competing teams of these berserkers all trying to smash each other."

-In saberhagens berserker novels the berserker planet-killers were doomsday machines which destroyed both sides and assumed the task of eliminating all life everywhere. They dominated the galaxy. This was the result of natural selection. Only one species can occupy a particular niche at a given time.

One of my favorites was about a severely damaged berserker brain which took refuge in a deep cave on a war-prone humanoid-inhabited planet.

It became a god to them and instructed them to hold gladiator games once a year amongst its greatest warriors. At the end of each game the single champion who survived was led into the cave to be rewarded by god himself. The berserker would then kill him.

It's logic of course being to weaken this species by systematically weeding out its most capable fighters. Kind of exactly what al quaida was created to do.

Saberhagen understood domestication very well.
Caliban
not rated yet May 15, 2014
would only be obvious if they produce waste (radiation)
And indeed this may be the only thing we could detect.

" Freeman Dyson's original articulation of this principle remains the simplest: search for the energy that a civilisation has used for its own purposes[...] the more efficient the civilisation is, the higher the entropy of the expelled energy, and the more it will have the properties of the sort we expect to see from waste heat."


Ghost,

I don't think that Dyson's thinking was very thorough around this concept.
Low-energy, high entropy heat is abundant and ubiquitous in the universe, and signifies very little, necessarily, about tech activity. What detectable trace has planetary civilization of Earth left in terms of energy signature detectable at distance?

Also, and again, he assumes all tech must be equivalent to current Human tech. Since we don't even know what tech we will have in a 100, 1000, 10000 years, how can this assumption be made into rule?
TheGhostofOtto1923
2.3 / 5 (3) May 15, 2014
Ya gots ta read the whole article.

"Now that we have sensitive mid-infrared surveys, distinguishing mid-infrared emission from dust and alien civilizations is the primary obstacle to detecting alien waste heat."
http://www.gizmod...ologies/

-And they are actually looking:

"The G-HAT search, then, will have two implications for SETI: we will put an upper limit on the size of energy supplies being emitted as waste heat in nearby stars and Galaxies, and our best candidates will inform a target list for communication SETI efforts. In this way, the Dysonian and communication SETI approaches are strongly complementary."
Since we don't even know what tech we will have in a 100, 1000, 10000 years, how can this assumption be made into rule?
Scientists choose to start somewhere. They assume that unusable waste IR would be generated, and they choose to look for it.
yyz
5 / 5 (3) May 15, 2014
"And they are actually looking"

Physicist Richard Carrigan Jr has carried out an all-sky survey for Dyson Spheres using IR data from the IRAS satellite. His study was published in the Astrophysical Journal in 2009: http://arxiv.org/abs/0811.2376

A search using more sensitive and discriminating data from Spitzer and WISE, like G-HAT, is a logical next step.
Caliban
not rated yet May 16, 2014
Ya gots ta reacommunication SETI approaches are strongly complementary."
Since we don't even know what d the whole article.

"Now that we have sensitive mid-infrared surveys, distinguishing mid-infrared emission from dust and alien civilizations is the primary obstacle to detecting alien waste heat."
http://www.gizmod...ologies/

-And they are actually looking:

"The G-HAT search, then, will have two implications for SETI: we will put an upper limit on the size of energy supplies
in a 100, 1000, 10000 years, how can this assumption be made into rule?
Scientists choose to start somewhere. They assume that unusable waste IR would be generated, and they choose to look for it.


Understood, but, I still gotta wonder where they hope to find deposits of this waste IR of sufficient magnitude to be detectable. It would require huge, very localized, waste output.

Good luck to 'em, just the same.
TheGhostofOtto1923
3 / 5 (2) May 17, 2014
Understood, but, I still gotta wonder where they hope to find deposits of this waste IR of sufficient magnitude to be detectable. It would require huge, very localized, waste output
Well according to the theory a Dyson sphere would capture the total output of a star. ALL of this energy would need to be re-radiated as waste heat, with a certain distinctive signature.

Unless they were somehow converting it into matter or dumping it in some other universe. Perhaps they could direct it toward some uninhabited part of the galaxy.

"Kardashev scale... A Type I civilization uses all available resources impinging on its home planet, Type II harnesses all the energy of its star, and Type III of its galaxy."

-But a machine singularity would no doubt want to use only what it needed to ensure its survival for the longest period of time.
jackjump
3.7 / 5 (3) May 17, 2014
Maybe intelligent civilizations (redundant?) pass through kindergarten rather quickly and move on to become part of the mature intergalactic community, communicating, conversing and otherwise hobnobbing with their fellow intelligent beings through means that would appear to us to be magic. Meanwhile we're trying to detect civilizations using primitive means of communication like undirected modulated radiation visible to everyone and everything. They're not looking for us and probably wouldn't care if they did notice us. We don't see what we're looking for because civilizations remain in kindergarten only a few hundred years at most, not enough time to fill space with weak signals. We have the problem deep forest Amazon tribes have in trying to contact the civilization they believe exists beyond their part of the world by beating drums and sending smoke signals. We already know they're there and we're not paying attention to their drums and smoke.
TheGhostofOtto1923
1 / 5 (1) May 18, 2014
We have the problem deep forest Amazon tribes have in trying to contact the civilization they believe exists beyond their part of the world by beating drums and sending smoke signals. We already know they're there and we're not paying attention to their drums and smoke
Sorry but unless you can provide a reference to support this, we can conclude that you made it up IOW utter bullshit.
Valentiinro
5 / 5 (1) May 18, 2014
We have the problem deep forest Amazon tribes have in trying to contact the civilization they believe exists beyond their part of the world by beating drums and sending smoke signals. We already know they're there and we're not paying attention to their drums and smoke
Sorry but unless you can provide a reference to support this, we can conclude that you made it up IOW utter bullshit.


Maybe indicates a guess. Of course he can't provide references that there's a mature intergalactic community communicating in undetectable ways that would appear to us to be magic.
TheGhostofOtto1923
1 / 5 (1) May 19, 2014
Maybe indicates a guess. Of course he can't provide references that there's a mature intergalactic community communicating in undetectable ways that would appear to us to be magic
No tard he needs to back up his bullshit claim that amazon tribes are trying to contact the developed world in vain.

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