Centauri Dreams regular Keith Cooper gives us a look at self-replication and the consequences of autonomous probes for intelligent cultures spreading into the universe. Is the Fermi paradox explained by the lack of such civilizations in the galaxy, or is there a far more subtle reason? Keith has been thinking about these matters for some time as editor of both Astronomy Now and Principium, which has just published its fourth issue in its role as the newsletter of the Institute for Interstellar Studies. Intelligent robotic probes, as it turns out, may be achievable sooner than we have thought.
by Keith Cooper
There’s a folk tale that you’ll sometimes hear told around the SETI or physics communities. Back in the 1940s and 50s, at the Los Alamos National Labs, where the first nuclear weapons were built, many physicists of Hungarian extraction worked. These included such luminaries in the field as Leó Szilárd, Eugene Wigner, Edward Teller and John Von Neumann. When in 1951 their colleague, the Italian physicist Enrico Fermi, proposed his famous rhetorical paradox – if intelligent extraterrestrial life exists, why do we not see any evidence for them? – the Hungarian contingent responded by standing up and saying, “We are right here, and we call ourselves Hungarians!”
It turns out that the story is apocryphal, started by Philip Morrison, one of the fathers of modern SETI [1]. But there is a neat twist. You see, one of those Hungarians, John Von Neumann, developed the idea of self-replicating automata, which he presented in 1948. Twelve years later astronomer Ronald Bracewell proposed that advanced civilisations may send sophisticated probes carrying artificial intelligence to the stars in order to seek out life and contact it. Bracewell did not stipulate that these probes had to be self replicating – i.e able to build replicas of themselves from raw materials – but the two concepts were a happy marriage. A probe could fly to a star system, build versions of itself from the raw materials that it finds there, and then each daughter probe could continue on to another star, where more probes are built, and so on until the entire Galaxy has been visited for the cost of just one probe.
The combination of Von Neumann machines and Bracewell’s probes made Fermi’s Paradox all the more puzzling. There has been more than enough time throughout cosmic history for one or more civilisations to send out an army of self-replicating probes that could colonise the Galaxy in anywhere between three million and 300 million years [2] [3]. By all rights, if intelligent life elsewhere in the Universe does exist, then they should have colonised the Solar System long before humans arrived on the scene – the essence of Fermi’s Paradox. The conundrum it is about to be compounded further, because human civilisation will have its own Von Neumann probes within the next two to three decades, tops. And if we can do it, so can the aliens, so where are they?
To Build a Replicator
A self-replicator requires four fundamental components: a ‘factory’, a ‘duplicator’, a ‘controller’ and an instruction program. The latter is easy – digital blueprints that can be stored on computer and which direct the factory in how to manufacturer the replica. The duplicator facilitates the copying of the blueprint, while the controller is linked to both the factory and the duplicator, first initiating the duplicator with the program input, then the factory with the output, before finally copying the program and uploading it to the new daughter probe, so it too can produce offspring in the future.
‘Duplicator’, ‘controller’, ‘factory’; these are just words. What are they in real life? In biology, DNA permits replication by following these very steps. DNA’s factory is found in the form of ribosomes, where proteins are synthesised. The duplicators are RNA enzymes and polymerase, while the controllers are the repressor molecules that can control the conveyance of genetic information from the DNA to the ribosomes by ‘messenger RNA’ created by the RNA polymerase. The program itself is encoded into the RNA and DNA, which dictates the whole process.
That’s fine for biological cells; how on earth can a single space probe take the raw materials of an asteroid and turn it into another identical space probe? The factory itself would be machinery to do the mining and smelting, but beyond this something needs to do the job of constructing the daughter probe down to the finest detail. Previously, we had assumed that nanotechnology would do the duplicating, reassembling the asteroidal material into metal paneling, computer circuits and propulsion drives. However, nanotechnology is far from reaching the level of autonomy and maturity where it is able to do this.
Perhaps there is another way, a technology for which we are only now beginning to see its potential. Additive manufacturing or, as it is more popularly known, 3D printing, is being increasingly utilised in more and more areas of technology and construction. Additive manufacturing takes a digital design (the instruction program) and is able to build it up layer by layer, each 0.1mm thick. The factory, in this sense, is then the 3D printer as a whole. The duplicator is the part that lays down the layers while the controller is the computer. It’s not a pure replica in the Star Trek sense, but it can build practically anything, including moving parts, that can otherwise only be manufactured in a real factory.
Gathering Space Resources
3D printing is not the technology of tomorrow; it’s the technology of today. It’s not a suddenly disruptive technology either (well, not in the sense of how it has gradually evolved), having been around in its most basic form since the 1970s and in its current form since 1995. Rather, it is a transformative technology. The reason it is gaining traction in modern society now is because it is becoming affordable, with small 3D printers now costing under $2,000. Within a decade or so, we’ll all have one; they’ll be as ubiquitous as a VCR, cell phone or a microwave. This will have huge consequences for manufacturing, jobs and the economy, potentially destroying large swathes of the supply chains from manufacturing to the purchaser, but, whereas the factory production lines on Earth may dry up, in space new economic opportunities will open up.
As spaceflight transitions from the domain of national space agencies to a wider field of private corporations, economic opportunities in space are already being sought after, including the mineral riches of the asteroids. One company in particular, Deep Space Industries, has already patented a 3D printer that will work in the microgravity of space [4] and they intend to use additive manufacturing to construct communication and energy platforms, space habitats, rocket fuel stations and probes from material mined from asteroids and brought into Earth orbit. For now, they envisage factory facilities in orbit and the asteroids mined will be those that come close to Earth [5]. Nevertheless, it has already been mooted that astronauts on a mission to Mars will be able to take 3D printers with them and, as we utilise asteroids further afield, we’ll start to bundle in the 3D printers with automated probes, creating an industrial infrastructure in space, first across the inner Solar System and then expanding into the outer realms.
Image: A ‘fuel harvestor’ concept as developed by Deep Space Industries. Credit: DSI.
Here’s the key; these 3D printers that will sit in orbit and are designed to build habitats or communication platforms, could easily become part of a large probe and be programmed to just build more probes. All of a sudden, we’d have a population of Von Neumann probes on our hands.
Without artificial intelligence, the probes would just be programmed automatons. They’d spend their time flitting from asteroid to asteroid, following the simple programming we have given them, but one day someone is inevitably going to direct them towards the stars. This raises two vital points. One is that if we can build Von Neumann probes, then a technological alien intelligence could surely do the same and their absence is therefore troubling. And two, Von Neumann probes will soon no longer be a theoretical concept and we are going to have to start to decide what we want them to be: explorers, or scavengers.
A Future Beyond Consumption
It seems clear that self-replicating probes will first be used for resource gathering in our own Solar System. Gradually their sphere of influence will begin to edge out into the Kuiper Belt and then the Oort Cloud, halfway to the nearest stars. That may not be for some time, given the distances involved, but when we start sending them to other stars, do we really want them rampaging through another planetary system, consuming everything like a horde of locusts? How would we feel if someone else’s Von Neumann probes entered our Solar System to do the same? Once they are let loose, we need to take responsibility for their behaviour, lest we be considered bad parents for not supervising our creations. That would not be the ‘first contact’ situation we’ve been dreaming of.
On the other hand, Bracewell’s probes were designed for contact, for communication, for the storage and conveyance of information – a far more civilised task. But standards, however low, can be set early. If our Von Neumann probes are only ever used for mining, will we be wise enough to have the vision in the future to appropriate them for other means too? It seems we need to think about how we are going to operate them now, rather than later after the horse has bolted.
And perhaps there lies the answer to Fermi’s Paradox. Maybe intelligent extraterrestrials are more interested in making a good first impression than the incessant consumption of resources. Perhaps that is why the Solar System wasn’t scoured by a wave of Von Neumann probes long ago. The folly of our assumption is that we see all before us as resources to be utilised, but why should intelligent extraterrestrial life share that outlook? Maybe they are more interested in contact than consumption – a criticism that can be levelled at other ideas in SETI, such as Kardashev civilisations and Dyson spheres that have been discussed recently on Centauri Dreams. Perhaps instead there is a Bracewell probe already here, lurking in in a Lagrange point, or in the shadow of an asteroid, watching and waiting to be discovered. If that’s the case, it may be one our own Von Neumann probes that first encounters it – and we want to make sure that we make the right impression with our own probe the day that happens.
References
[1] H Paul Schuch’s edited collection of SETI essays, SETI: Past, Present and Future, published by Springer, 2011.
[2] Birkbeck College’s Ian Crawford has calculated that the time to colonise the Galaxy could be as little as 3.75 million years, as described in an article in the July 2000 issue of Scientific American.
[3] Frank Tipler’s estimate for the time to colonise the Galaxy was 300 million years, as written in his famous 1980 paper “Extraterrestrial Intelligent Beings Do Not Exist,” that appeared in the Royal Astronomical Society’s Quarterly Journal.
[4] Deep Space Industries 22 January 2013 press announcement.
[5] Private correspondence with Deep Space Industries’ CEO, David Gump.
These Von Neumann machines are fine in the abstract.
I agree that all it is plausible to design a Von Neumann machine, but how do
you test one. These machines are going to be traveling for millions of
years. If you give these things sentience, who knows what they will do
with themselves over time. And as I mentioned before they will surely
get tired of the same diet of Lifeless wasteland of planets. How many
times can a sentient program stand being disapointed? What this
machine cannot be dissapointed? Then it is surely not sentient.
And If you don’t give them sentience then
they will most likely fail and the Von Neumann expansion waves will sputter and die, as they guaranteed to run across a problem that they can’t solve.
It is possible a non sentient of space probes effort may weave a net of a couple of hundreds of light years and theese machine may be equivalent of a Marker. But once again since we have not found such a marker in our solar system it implies technological civs do not arise often and are not permanent.
Thanks for an intelligent treatment of the Paradox. I’d like to add this thought…Kepler telescope is fueling a lot of excitement because its method works. Hence the method is likely universal…So we know that the the likelihood is high that we are being observed as we transit our sun. if so then we know where to target our searches: directly opposite our sun especially when that brings us into alignment with the Milky Way. That is where we were visible to an alien Kepler.
Perhaps the fleet will appear somewhere across that particular swath of sky…or at least a carrier signal.
Solutions to this issue have been proposed. If first civilization is conservative and wants to let younger ones develop on their own, then it could bring down such probes by new civilizations(especially if it has technology advanced by millions or billions of years).
Another possible solution would be that economic consequences of 3D printing such rise in unemployment, availability of weapons, eventual ability to produce chemical or biological wmd’s by individuals brings social collapse before space colonization becomes possible.
Just two ideas…
Also there is no need for Von Neumann Probes to seek other life. We know know that telescopes will do fine, and very advanced concepts would be more beneficial than Von Neumann Probe. A civilization with technology to build such machines already will know where to send them, so they need not to replicate themselves across countless unexplored stars-as those stars will be surveyed by telescopes already.
3D printers are a neat technology, and they will make some things easier, but I think the focus on them as a necessary part of self-replicating systems is just as far off as thinking nanotechnology is necessary. All of the parts of our current factory machines (mill, lathe, drill press, etc) are made using our current factory machines. All it takes is sufficiently dextrous robotic manipulators to put the raw materials in the tools and then assemble the parts that come out of the tools. A self replicating factory like this might be the size of a city, and maybe you could make it smaller with 3D printing, but I don’t see any showstoppers for a self replicating factory based on old-fashioned pour the molten metal into a mold, take the resulting ingot and cut parts of it away using other metal tools made in the same way.
They won’t get far before the Singularity takes over anyway.
The presupposition of intelligent life being more “connection oriented” than “resource oriented” seems naïve. The point is we don’t know. But if we focus on the project at hand of getting these things out there, and also enhancing intelligent life on Earth, then maybe 10 or 100 of these things can be “out there” by the time the Singularity takes over. It should only take a short amount of time (a few hundred light-years at max) for the Singularity to be able to upgrade them remotely, to be better able to handle resources or any possible alien intelligent encounter. If the intelligent alien civilization was also post-singularity than the transition and merging should be even easier…
We may not be able to separate consumption from “making a good first impression”, because life, even artificial life, must consume to perpetuate, regardless of presentation. For example, teaching college students professionalism isn’t easy, because the standards defining professionalism differ as perceived by traditionalists, boomers, and millennials. However, they will definitely agree that the goal is to progress in life, to make a living wage and live comfortably.
Regarding impression, we could program replicators to “waste not”, in other words treat material extraction with the goal of zero waste. We could also program them to minimize environmental degradation. But extrapolate replicator influence on a solar system scale, and you have a tendency to use every resource available. So much for wilderness and pristine places.
Here’s another thought experiment. Say a replicator landed in Los Angeles and started drilling, dismantling buildings, spewing out tailings, and reaching it arms out to drag ‘resources’ into its input and sort facility. We humans would react to that fairly predictably: by waging violence against it. So, I summarize to say we need to consider programming autonomous replicators with sensitivity for reciprocal relations with the environment. Even if that environment is non-living and non-sentient, conflicts can arise. If we ever want to vacation on Titan several epochs from now, we wouldn’t want to have mined all the hydrocarbons, creating a tar sands open pit mine with our replicators, would we? Would we want to give that ‘impression’ to the civilization that finds our remains in the stars? I think the paradox can be resolved if we consider that impression and consumption cannot be unlinked. The necessary intelligent heavy machinery for populating deep space precludes our ability to exude “professionalism” among the stars.
Concerning the Fermi paradox an alternative view.
http://news.yahoo.com/could-life-older-earth-itself-175255318.html
What about biological replicators capable of spreading their seed throughout the galaxy (borrowing from the panspermia theory of life)? One of Larry Niven’s short stories set in his Known Space universe featured genetically engineered plants called “stage trees” bred by an ancient, long dead alien race called the Tnuctipun. Stage trees could create rocket fuel in their trunks via photosynthesis. When enough fuel had been generated they blasted off from their home world and spread copious quantities of seed pods into interstellar space. Over the eons some of the seed pods have been passively swept into the atmospheres of Earthlike planets, where they have taken root, grown, and repeated the life cycle. After several billion years, stage trees have spread throughout the galaxy as a sort of interstellar weed.
If you wish to dabble with nanotechnology then you will need molecular 3D printers that will be 100 000 x smaller. We can currently or are close to been able to use 3D printers to ‘print’ -with- organic cells, so printing organs etc is possible, maybe even a brain (neuron) structure.
It is always possible that the Von Neumann machines are life itself, and that those species that manage starflight propagate themselves. This might make sense if life was very rare and civilizations hoped to create more intelligence by seeding the cosmos. This seems like a more worthy goal than just rapaciously consuming resources.
Or buried on the moon, waiting to be uncovered…
If there are VN machines, we should expect to have a number of different ones in evidence, as each civilization introduces its own design.
And for a wildly speculative idea, concerning whether we would recognize alien presence in the universe or not: what if the accelerating cosmological expansion is not a natural phenomenon, but rather the pollution/side effect of some hyper velocity star drive? (I’m twisting Clarke’s short story “Superiority” so that instead of the ships changing size, it is the universe).
I don’t believe we will travel to another star until we have definitely found a planet that can be an Eden. That can only happen if we send probes to multiple systems, and the probes need to be self refueling and self repairing, because after a centuries long journey, they will have to travel close enough to each candidate planet to analyze the atmosphere, the land, and the ocean.
If the probe can repair and replace every piece of itself, from fission breeder reactors to computer chips to manufacturing tools, it can essentially replicate itself.
I’d be very careful about giving sentience to a probe. An uncontrollable immortal that can throw rocks back at 10% light speed? That would be bad. Maybe you could build something stable and trustworthy if the sentience was a society of minds, but still — caution! caution!
http://www.reddit.com/r/IAmA/comments/199f0n/im_andras_forgacs_ceo_of_modern_meadow_a_company/
If this works its disruptive in a positive way.
Sagan and Tipler had this same debate on the Fermi Paradox about the consumptive intent of ETI BTW Tipler nowthinks they exists just not in our galaxy
@coacervate That’s a good idea, do SETI localized to the plane of the ecliptic, except that it really only applies to civilizations near our own level of technology. In a relatively short time we’ll have space based interferometers and StarShades, and ultra-high precision rv spectrographs that will relax this requirement. Though some of the first systems they’ll observe will likely be those discovered through transits. A civilization even a few thousand years advanced should be able to find most of the planets similar to their own in terms of mass, temp, and maybe even atmosphere, throughout most of the galaxy.
There are a few different answers to the Von Neumann angle on the Fermi paradox.
First – ETI could be just as aware of the dangers posed by “gray goo” as we are. They might want to avoid creating a wildfire of robots that consume everything within reach.
Second – correct me if I’m wrong, but wouldn’t self-replicating robots degrade over many generations? It would be like inbreeding – minor flaws and malfunctions slowly add up, becoming exacerbated over time until eventually, the last generation of bots is sterile (unable to reproduce). Unless you gave sexual reproduction to robots to maintain their “DNA” of central programming, and then you’re creating an artificial species. Which goes back to the first point, since creating a robot species competing with you for resources would inevitably bring trouble.
Third – As I’ve pointed out before, the universe is huge and not fully mapped. A probe may have visited this solar system in the past and not been noticed. They may have not expanded to this corner of the galaxy yet. They may be on the other side of the galactic core, thus invisible to us. They may have turned inward (virtual reality etc.) instead of exploring the universe. And even if we’re the only intelligent species in this galaxy, there are many other galaxies.
What I’m really getting at in the third section is that the Fermi Paradox doesn’t disprove aliens. It just means that there are no highly advanced expansionist ETI within our vicinity.
@excalibur re: point 2…Most of the flaws and malfunctions would be detrimental. Occasionally there would be benefit and the probe would become better suited to its environment. Who knows where that process could lead? Heh.
@coolstar, i do agree but i offer the technique as a point of difference The pond is too big to cast about blindly. Listening at the right time and in the right direction needs some logical strategy….a means of doing targetted searches where both parties can logically deduce a higher degree of uniqueness among the teeming masses. The Kepler planets will be our historical reference point…a good place to start looking. In practice we would time our message to arrive during a transit…If they do likewise, we could establish matched pairs that “co-transit”.
Since I read the article a while back: “Could life be older than Earth”
It has got me puzzling over what appears to be a very simple solution to the Fermi Paradox. If its true we are among the first (if not very first for any massive distance out). In that case our probes will litter the cosmos and how we choose to implement them will have profound effects downstream in time.
Regarding the design of a probe system I think we’re limiting ourselves by visualizing circuit boards, manipulator hands, etc… I think redundant “DNA” instructions etched into diamonds would contain the commands, while genetically designed virus’s coat their exteriors. When the appropriate conditions occur (say 10AU out from a target star), the virus “wake” up to consume feedstock secreted in the rock ship. Each genetic growth stage triggers a more complex creation, culminating in something like a memresitor based intelligence, also programmed from diamond based instructions. It then goes on to create bio-based factories which create the metal panels, chips, etc.. necessary to probe the system. Its my impression that our rate of bio-control is growing faster than nano-manipulators… so why not synthetic biology?
Bootstraping itself up to cognizance only during exploration activities, launch micro-asteriods back to earth with diamond data centers, build another core daughter probe and launch them. The daughter probes need only the core instructions and the boostraping viral synthetic life.. Just takes a mastery of genetics and long term stable storage…
Quantifying the impact of von Neumann Machines requires knowing something about their likely size and replication times. Robert Freitas designed a self-replicating interstellar probe (REPRO) based on “Daedalus”, which massed 10,700,000 tonnes when fully fuelled and took 1,000 years to self-replicate. If such large probes arrived in our Solar System every 1,000 years then 4.6 million have arrived over the age of the Solar System. If they make daughter probes and launch them off to other stars every 1,000 years, then about ~1.12E+23 kgs of mass in the Solar System has been used – most of it from a suitable gas-giant, being fusion fuels. To give some perspective, that’s just a bit more than the Moon in mass, or a largish asteroid if we keep the hydrogen/helium fuels separate.
Doubling the trip time would dramatically reduce the mass, as the vehicle would then be able to decelerate for a total launch mass of just 110,000 tonnes. Such a REPRO could then self-replicate in just a couple of hundred years, as well as conducting an extensive survey of its target system via a vast array of sub-probes made in-situ.
The total mass utilized in any star-system becomes very small as the abilities of such machines becomes ever more capable in ever smaller masses. Freitas, these days, is a vocal advocate of nano-technology – nano-tech star-probes could explore the Galaxy for trivial amounts of total mass per star-system explored, thus we’d never know if our system had been explored unless we literally turned over every rock in the system. Even then self-dissolving probes would make the search even harder if such Galactic explorer networks wished to remain indetectable.
All such SETA (Search for Extraterrestrial Artefacts) arguments assumed naively that ETIs will be limited to large inert chunks of “dumb” matter. But, as seems likely for us, if the trend is towards “smart matter”, then finding any recognizable remains will become immensely hard. Much of our nano-tech is organic – witness the marvellously expanding engineering tool-kit we’re making of the abilities of DNA and its cousins – so the possibility of finding recognizable technological traces, rather than organic crud processed by UV and high-energy particles, is also becoming somewhat remote. If ETIs use auto-consuming designs, to prevent detection or runaway growth, then the evidence will elude us utterly. Apoptosis and autolysis in our own bodies and cells serves a variety of useful purposes and quickly reduces our bodies to inert food-mass for bacteria within a day or so of dying, without being a design feature.
“Perhaps instead there is a Bracewell probe already here, lurking in in a Lagrange point, or in the shadow of an asteroid, watching and waiting to be discovered.”
This brought to mind the old paper by Scottish British Interplanetary Society member, science writer and sci-fi author Ducan Lunan.
Lunan’s 1973 paper which postulated that the still as yet unexplained phenomenon of Long Delayed Echoes (LDEs) were the work of an alien probe from Epsilon_Boötis parked at L5.
Here was his paper, published in Spaceflight, the journal of the British Interplanetary Society – (‘Space Probe from Epsilon Boötis’, Spaceflight, April 1973; reprinted Pursuit, 1975; illus. Ed Buckley and Gavin Roberts.) and re-published by Analog – (‘Space Probe from Epsilon Boötis?’, Analog, January 1974; illus. Ed Buckley and Gavin Roberts.)
http://adsabs.harvard.edu/abs/1973SpFl…15..122L
The theory was part of the inspiration of Mark Brandis’ 1974 sci-fi novel Raumsonde Epsilon (in English Spaceprobe Epsilon).
See also (‘Long-Delayed Echoes and the Extraterrestrial Hypothesis’, Journal of the Society of Electronic and Radio Technicians, September 1976.)
Another article ‘Epsilon Bootis revisited’ appeared in the March 1998 issue of Analog. (‘Epsilon Boötis Revisited’, Analog, March 1998; illus. Nick Portwin)
Of interest here’s a bibliography of Lunan’s other published work: http://www.jeffhawkeclub.com/cv_pubwork.pdf
I’m not sure why but the link to the abstract of Ducan’s original paper got mangled.
If one goes to http://www.adsabs.harvard.edu and enters the bibliographic code: 1973SpFl…15..122L into the search field it will come up though.
A great thread today. I too doubt that this is a heretofor unexplored star sytem. Many faraway ‘eyes’ and sensors will long ago have known about and forgotten about the 8 planets at this Small Yellow Star XIIXRRM5377, one of billions. And some subset of them will have sent all kinds of probes to look closely and probes to fly past. Some subset of those will be top-of-the-line self replicators. And some subset of those may adapt to survive the unknown. And some subset of probes will be anti-probe probes, seeking to predate upon the others they find. Some frozen solid dead probes are likely adrift around here somewhere. I wouldn’t be surprised if there was one or two still ‘alive’ and passing messages out. Be glad there are none of the Oblivion movie style AI probes here now. Although that type of AI self replicator may have spent time at this star or even this planet in the past epochs, and such a thing might appear here in a future age. We’ve only got 5000 yrs of recorded history so far.
@Adam, I agree with what you say about the probable size and intelligence of any probes already in our system. They are probably very small, very smart and impossible to detect. The solution to the Fermi paradox does lie in the concept “we haven’t seen them because they don’t want to be seen”.
I know, that only begs the question, which is how can we rely on a concept that depends on NONE of them wanting to be seen? Maybe some probes are launched with stealth and discretion as their Prime Directive, but what about those from civilizations who have no interest in such things. The answer to THAT question always gets back to the idea of First Civilization. If the First Civilization a) is far back enough to be immensely superior to all others [even the 2nd civilization) and b) has a Prime Directive that includes absolute non-intervention [meaning virtual invisibility of its probes] and c) has a corollary to that Prime Directive that says “any other probes found will be destroyed so as to protect the Prime Directive”… if all those conditions are met, then the Fermi Paradox is answered.
However, such an answer is essentially untestable and thus quite unscientific.
I’d like to ask a side question, however. How long have heavy elements been around? We all assume that earth is late in coming, that habitable planets must have been around a billion or more years before the formation of our solar system. Is that true?
What is the data on “distribution of heavy elements throughout the Milky Way Galaxy over time”?
Maybe there hasn’t been that much time for Other Evolutions to occur. Maybe we are the First Civilization.
Keith Cooper: Excellent article, and right on the money, in my opinion.
I feel compelled to address a few misconceptions (IMHO) I saw in the comments, please humor me:
Rob Flores:
Not true, I think. There are plenty of non-sentient creatures doing just fine in environments on Earth that are far more challenging to navigate than empty space, stars, and rocks.
Wojciech J:
This assumes the entire population descended from the origin somehow thinks and acts as a single unit, over interstellar distances. That is not plausible, at all.
Wojciech J:
Not so. There are simply not enough quanta of light coming our way. There is millionfold more information to be obtained by orbiting a world and landing on it than any telescope can ever provide, no matter how powerful.
xcalibur:
Unless purposely built to do battle, such machines would be extremely vulnerable and no threat to anyone. Pull the plug, hack the computer, bomb the CPU, your choice. The generation time would be years, if not decades, so it would be a slow wildfire, too. Mighty and overwhelming in the long run, yes, but only if allowed to proceed unchecked.
xcalibur:
No, it is quite easy to ensure a 100% perfect replication of the robot’s “DNA”, with the chance of survivable (or any) errors reduced to once in an arbitrary number of trillions of years.
xcalibur:
We are talking the galaxy, not the universe. While large, it can easily be traversed within a very small fraction of its age. Any spreading wave of VN machines will cover it entirely during this time period. It is not very plausible that some parts of the galaxy would be missed during this process, given enough time. You can bring up many explanations as to why ONE civilization might not spread in this way. What you have not done, and what is extremely difficult, is explain why NONE of them would.
Adam: It is true that VN probes could easily be made stealthy and inhibited from spreading out in every solar system they visit. Instead, they would limit themselves to enough facilities to produce the next generation and likely also a low-level permanent presence in the system. We might not have detected such a presence today, even if it were there. But, by your own calculation, 4.6 million such machines might have come here over the ages. Presumably, of many different makes and origins. Is it really plausible that they ALL kept this low profile, without fail, and without trampling on each other’s toes? Or ours?
If we are going to assume very advanced technology, why assume the probes will remain in orbit? They could be here on earth, taking the form of rocks, plants, animals etc. Neither do we have to assume that replication occurs until resource depletion. They could maintain a low density simply by communication.
The problem I see with any of this speculation, is that the “invisibility” of the probes/aliens can always be postulated on some advanced state of technology just beyond our reach (e.g. nanotech). And like SETI, failure to confirm their presence just leads to ever more approaches to search. It is vaguely like witch hunting, where it was assumed the sign of the devil was somewhere on the witch, resulting in torture, extraction of teeth etc, in an attempt to find “the sign”.
It may well turn out that intelligent, technological, star faring life is incredibly rare in the universe. Hopefully life is more common, and that this hypothesis will be testable within a decade or two. OTOH, maybe they are out there in plain sight, but we are too blind to see the obvious, while we look for the ant equivalent of foreign pheromone tracks, scouts and super anthills.
I think we need at some point to face up to the growing evidence that we’ve lucked out, WE are the ‘elder race’, with an empty galaxy available to colonize.
Which also suggests that it’s a dangerous galaxy, and we’d better get cracking on colonization before the universe up and provides some other, yet to evolve, race, with an empty galaxy to colonize.
By the time we have interstellar propulsion technology, we should have mature nanotechnology and will not need 3D printing.
Hi Alex Tolley
Fair point, but one is then assuming no knowledge of the other probes by the earliest arrivals and no interaction. If they do interact, then over the billennia I suspect a common “ethic” or “Code of Conduct” will develop – which someone will enforce.
“Centauri Dreams” has discussed Claudio Maccone’s work on gravitational lensing – the incredible amplification of signals it allows, enabling cross-galactic communications for trivial amounts of signal power. Thus even small probes will be connected to a Galactic network, allowing some kind of homogenisation. Remember such probes will be immensely long-lived and immensely patient, due to the time-scales they operate on. Ideas and dogmas will propagate slowly and remain stable.
We always seem to imagine *some* fraction of the probe population deviating from the norm, but no one imagines the countering “enforcement” that might also exist. Forcible take-over of a probe’s OS or personality might well be the preferred “punishment” if the dominant ethic is to observe unobtrusively.
Then again maybe we are the Elder Race, in which case these sorts of discussions may help us design self-replicators we can live with.
We are not the “first civilization” . We (mostly of the West) make that ethno-centric and temporal-centric mistake again and again and again. Rome is not eternal. HSapiens is not the be-all and end-all of anything. The sun doesn not revolve round the Earth. The stars do not revolve around ‘our’ sun. Our sun is not unique at all. And the Milky way is not the universe. And likely, this is not “the” universe, but “a” universe.
It will hurt our ego when we find that the ‘Sun’ is called many many older names. Just a number on many old old forgotten map of others before us. Been lots of water under the bridge before we were born.
David April 27, 2013 at 11:05
“However, such an answer is essentially untestable and thus quite unscientific.”
Well, so far we haven’t heard from ET or seen them, so it is one of the most plausible ones.
Eniac:
“This assumes the entire population descended from the origin somehow thinks and acts as a single unit, over interstellar distances. That is not plausible, at all.”
Why not? Both you and I know nothing about any such civilization. It might be a hive mind or a single individual. As to acting as single unit-we already did this as civilization on treaties regarding Antarctica, nuclear weapons in space and so on. Making joint decisions is not far-fetched.
“There are simply not enough quanta of light coming our way. There is millionfold more information to be obtained by orbiting a world and landing on it than any telescope can ever provide, no matter how powerful.”
You didn’t get the point. There is no need for Von Neumann probes, because you can direct probes to precise points in space that you can detect with telescopes. There is no need for mass replication across the galaxy to search for life-bearing worlds and other civilizations.
“You can bring up many explanations as to why ONE civilization might not spread in this way. What you have not done, and what is extremely difficult, is explain why NONE of them would.”
That assumes there were many. Which might not have been the case, and if there was one that wanted to prohibit this-and billions of years advanced-it would easily stop them.
coacervate-good idea!
Also I might mention that the problem with Von Neumann probes is the same as SETI-it assumes civilizations will build them. It also assumes that civilizations will be be beaming radio signals for billions of years with immense power across space. Well, how many times we had done, despite our technological ability to do so?
David:
“I’d like to ask a side question, however. How long have heavy elements been around? ”
Heavy elements (from Born on up) are formed in largish stars (somewhat less than Sun size on up). They’re about 10-15% of the stars we see, and they tend to have short lifetimes — the bigger, the shorter. Also, the bigger stars create heavier elements. The sun, in its old age, 5 billion years from now will be creating some carbon in its core. A supergiant, 20 times the sun’s mass, will create iron in its last few years of existence. Heavier elements than iron are created (and spread across the galaxy) only when those supergiants explode as supernovas. So, no supergiants, no supernovas, no nice silicates for building rocky Earth-like worlds. So your question becomes, “How long have supergiant stars been around, and how many and how long do they last?”
Some of this is answerable. We know here aren’t a whole lot of supergiants at any given moment; on the other hand, their lifespan is measured in millions or maybe tens of millions of years. We catch sight of one exploding in our galaxy maybe once or twice a century. Maybe there have been 10E8 (a hundred million) in the Milky Way since its formation roughly 10 billion years ago? (Out of maybe a trillion stars of class M thru A.)
But how long have supergiants been around? Thinking was, supergiants formed in galaxies or galaxy-sized gas clouds, which would have put the oldest of them at say 10 to 11 billion years ago. But this last year or so, we’ve observed at least one supernova with a red-shift indicating an age of say 12.5 billion years or more — within a billion years of the Big Bang.
So, with some handwaving, it’s conceivable that life — even intelligent life — might have evolved in the universe before the appearance of our galaxy and thst some sort of galactic civilization may have been around for over ten billlion years — twice the life so far of our own solar system.
Having been a technician and troubleshooter for most of my life it is my opinion that manufacturing and keeping things working is a far more complex activity than academia and engineers suppose. While the news has been putting out stories like this for half a century-
http://www.independent.co.uk/news/science/one-giant-leap-for-mankind-13bn-iter-project-makes-breakthrough-in-the-quest-for-nuclear-fusion-a-solution-to-climate-change-and-an-age-of-clean-cheap-energy-8590480.html
-there has been no “breakthrough” and may never be. Why? Because while a star or a bomb can produce fusion energy as advertised, making a star burn in a little box is not like lighting off a bomb at all.
Making “robot replicators” may be just as elusive. It may sound easy but what we do as evolved tool using creatures may be impossible to replicate with machines.
Thanks for an exceptionally interesting article and discussion. In many ways I rather hope we are the first advanced civilisation, although the odds seem to be heavily against it. The point several people make around the presumed invisibility of any probe raises serious questions as it does, if totally correct, make the whole thing untestable. If such probes are present it is probably reasonable to assume they are very far ahead of us technologically and one wonders if there is any standard set of features that any and all such probes would have to display that could be diagnostic and not lead to the observer being declared to be a ‘nut’?
No ready answer to that one. Best I can think of it that they would have to expend energy and would display behaviours suggestive of control whilst not conforming to any current technological device in terms of performance characteristics. Conscious that can hardly be definitive. Any advances on that?
In a way, I suppose one could even classify a world ship as a type of Von Neumann probe. It’s a completely self-contained system (ship) that, upon arrival at a new star system, is capable of producing a replica of itself from raw materials (albeit, not an exact one – since its biological components likely wouldn’t be clones of the original set) that can then go on to a new destination to repeat the process.
@mike shupp, how could you give that lecture to David without mentioning those mysterious population III stars.
@Wojciech J in his reply to ENIAC. A hive mind just exasperates the problem, since the colonies are isolated by the speed of light, but their cognitive genes are selected for by the local environment, and also subject to genetic drift. Since it is impossible for each colony to wait to integrate the thought of minds from their home planet before they make local decisions, these will not play any part in them. Thus they would likely be more independent of each other than even human colonies.
Also, if there are as many emergences of new intelligent life as many SETI enthusiasts like to believe, it is unlikely that the first expansionist ETI had sufficient lag time to complete colonisation before the second arose.
It is for similar reasons that I propose that IF there is any equivalent of a “prime directive” in our galaxy, it could ONLY by the by-product of a universal law that ended a period of protracted early conflict in the Milky Way.
quote:= “”We are not the “first civilization” . We (mostly of the West) make that ethno-centric and temporal-centric mistake again and again and again. Rome is not eternal””
We are not arguing that we might be the first from an ego-centric desire to be first. If the article we are referencing is correct then its taken this long for the universe to make complex life. This is from an attempt to mathematically calculate evolutionary pacing. This would also align with no examples of “green” dyson enveloped stars or other mega-engineering, the lack of anomalous fusion flames, or seti detections of either optical or radio wavelengths, etc…
The problem with the Copernican principle is that someone has to be first (at least in our light cone). Given how long it took before intelligence developed on earth and the timing of our appearance in its liveable history we could be the last, assuming we’re a little under mid-way through the earths liveable phase (Solar output changes).
Wojciech J:
Mainly because of the communication lag. Even for us slow-thinking bilogical units decades is a very long time to wait for advice. There is no way that anyone will wait to obtain the opinion of those on another world before they make a decision. Future possible AI descendents of us will likely think and make decisions even much faster, with correspondingly less of an inclination to wait for decades to coordinate.
Thus, any substantial degree of interstellar coordination is not plausible, at all.
Oh, so you are saying we don’t need self-replication because we know exactly where we are going? Well, first of all, I think we would still like to go everywhere, anyway, no matter how well we can see ahead. Or are you saying with sufficiently powerful telescopes we will find most stars too uninteresting to explore further?
In principle, you are right: Self-replication is not really needed. We could just build 200 billion probes right here on Earth and send them all out across the galaxy. However, self-replication would be awfully nice to have. You could achieve the same thing with building just one. You’d be done in a century, and all you needed to do after that is sit back and listen for an exponentially rising flood of information to come in.
If there were only very few civilizations, we’d be back to the question of why so few. We might as well be alone. And with the “easily stop them” we’re back to the time lag cunundrum discussed above, which will not allow such tight coordination across interstellar distances, or much of any coordination at all.
Also: Consider that even if there are only a few species (collection of beings with the same origin), each species will inevitably be split up into many civilizations (beings joined in some sort of coordinated collective). At least one per star system, as per the above-mentioned communication lag conundrum. Probably a lot more. You will then have at least as many civilizations as settled stars. Quite a herd of cats, especially if it takes decades to send orders and verify compliance.
There clearly is no such thing as interstellar enforcement of anything.
Though I am sure it has been mentioned or at least hinted at by other comments, I want to state is another plausible solution that I have been thinking about for a while:
A swarm of Van Neumann Probes, regardless of whether they are truly intelligent or just programmed automatons, which merely consumes and expands endlessly (even if it also sends useful data to its creators) might very well be considered a plague, a sort of technological cancer on the universe itself, by some alien beings. Maybe some of them are actively hunting down and destroying Van Neumann Probes and that is why the Milky Way is not brimming with them.
mike shupp April 28, 2013 at 6:47
Thank you for that excellent answer to my question. What you say makes me think that the concept of humanity being the First Civilization is highly unlikely. Not impossible, but highly unlikely. It means we have to consider other answers to the Fermi Paradox, many of them listed here in this discussion, in other excellent posts.
I hate to keep repeating myself with the word “excellent” but there is no other word to describe this website, this blog, and these comment sections at the end of each blog entry.
Nowhere else on the web have I been able to find discussions regarding subjects such as these where the level of the discussion remains serious and sincere. Elsewhere things breakdown into a hodgepodge of alien abduction stories, creationist rants and just plain scientific illiteracy. Centauri-dreams.org is without a doubt the best science discussion site on the web, at least in my experience.
Obviously the credit goes to the moderators. They probably weed out a lot of junk posts.
Keep up the good work.
Eniac:
The replication process itself may approach 100% accuracy, but the data and the equipment doing the replication is likely to have been damaged already on the 1000+ years it’s been travelling. The issue of storing data over long time-frames is difficult even on Earth’s surface.
TARMEN Wrote:
“We are not the “first civilization” . We (mostly of the West) make that ethno-centric and temporal-centric mistake again and again and again. Rome is not eternal.”
I grant that we are not the 1st, but I submitt there have not been very many, and they have not been permanent.
If I am wrong and there is a plethra of civs out there, and there is a 1st Civ
older than the solar system, then once we venture a few hundred light years
we shall surely find the oldest. They will probably announce their prescence
with “THIS PARSEC IS A REFUGE DO NOT ATTEMPT TO ENTER, THIS
IS YOU ONLY WARNING!
Since we will be able to beam data to reprogram any interstellar craft, one does not have to figure out how to create a self-replicating probe at the time of launch. The probe just has to have enough capability to sense, extract, process, and manipulate material.
Also, a sufficiently intelligent civilization should be able to reprogram its probes to not only replicate itself but to make the tools to reproduce themselves (i.e. the senders) in biological form. Most all exoplanets would then be brimming with life…but they aren’t…???
If a Bracewell probe is sitting in our solar system, waiting, then it’s senders would be intelligent enough to know that we will be developing in a manner which brings us much suffering (disease, death, war, natural disasters, psychologic trauma, etc). The senders would also be smart enough to fix all of our problems. So what would motivate them to let us suffer? They wouldn’t want that for themselves, would they? What’s going on here?
JohnHunt:
A camera team shooting a wildlife documentary do not usually step in to help the animals they’re filming.
Also, if we assume that light speed is the limit on information transmission, then there probably hasn’t been enough time for the signal describing our emergence as an intelligent species to have reached their homeworld.
JohnHunt, I can’t understand why you could even think that an ETI had high interest in human stress levels. Note that the current technological species on a planet might not even be the most intelligent species there. It makes sense that humans project their own empathy on other humans to the exclusion of all other species, but why would, but why would some arthropod-like ET.
So, if they are keen to contact us with advise, that advice is going to be over how we can make our own living while maintaining ecological balance and species diversity in our biosphere (a planet that we posit they are studying) isn’t it?
Indeed. I was meaning to get back to this.
Eniac, are you sure they could stay so pristine? Consider a cosmic ray hitting a replicator and flipping a few 1s and 0s in its “dna”. Those flaws and mutations would be passed down to the next generation, most likely becoming more aberrant over time until you get sterile robots. They can be armored, but only to a point – they’re not invincible, and space is a chaotic environment.
And if they had artificial sexual reproduction, mixing artificial dna, you’re opening a pandoras box of evolving robots.
That is a difficult question. Our current observations favor either no ETI or rare ETI in the Milky Way Galaxy. If there’s only been several intelligent races in this galaxy, it is not improbable that none of them flooded the galaxy with probes or other obvious signs of their existence. Then of course, there is time as well as space – as I like to point out, our first alien encounter may be with ruins and artifacts. It’s possible that we haven’t noticed ancient defunct probes floating through space. They could be mistaken for a small asteroid.
And using Earth as our only working example, biology here supports the hypothesis that intelligent life is rare. There has been a huge abundance of life on earth for most of its history, but we don’t know of any other intelligent races aside from the homo genus.
Not really. We can very easily come up with data carriers that will last millenia. Multiple replicates and mathematical tricks like forward error correction (http://en.wikipedia.org/wiki/Forward_error_correction) even more easily ensure replication accuracy at any level you may chose. Less than 1 bit in 1 trillion years, for example. Or, if that is not enough, just double the carriers and you have 1 bit in a trillion trillion years. Constant recopying onto new carriers that occurs naturally during replication will make the information eternal for all practical purposes, even if the physical carriers last only a few millenia. The physical manifestations are constantly discarded and rebuilt from blueprints, so their form will be maintained eternally, too.
Now, we may, of course, decide that we want the machines to evolve, to a certain degree. To experiment, and to incorporate improvements into their coding, intentionally. That is possible, but should be thought through very, very, carefully. It is certainly not required.
Vershner:
Maybe not some camera teams, at least no until after the shoot. However, researchers, game wardens, and veterinarians will definitely help animals in need. So will tourists and kids in their backyards. Are you ready to include any of those in your analogy?
Rob Henry:
And yet, cetaceans, for example, receive an inordinate amount of empathy from us humans these days. Despite not being smart enough to even carry a conversation. So, why should not we get similar treatment from our arthropod superiors?
What should such a probe do, say, about war? Let’s say it were able to remotely disable all missiles, nukes, tanks, fighter jets and so on, permanently; maybe even all guns. People would still fight, even if it involded clubs or knives. So the probe would have to take those from us. Ad finitum. We would end in a state like the movie I, Robot, where the AI decides to imprison everyone and take away all freedom in order to protect mankind itself, not a good prospect either.
But in the end I don’t think any probe would be able to do that. The most it might be able to do is create some kind of message telling is to stop killing each other, see how well such warnings coming from thousands, maybe millions of people, have worked so far. Most of our problems are not caused by lack of knowledge or technology anyway, but by lack of will to change our behaviour even in the face of overwhelming evidence.