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Thread: The Fermi Paradox, Self-Replicating Probes, & Interstellar Transportation Bandwidth

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    The Fermi Paradox, Self-Replicating Probes, & Interstellar Transportation Bandwidth

    Here's an interesting paper from arxiv suggesting SRPs in our solar system might well be awaiting our discovery, and that lack of serious consideration for such self replicating probes has left a gap in our SETI investigations. I'd have to concur.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    A Very interesting paper. Not sure I agree with searching for ET in other Galaxies though. Like the idea of searching for SRP's in the solar system which seems somewhat plausible.

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    If an alien space ship capable of travelling here, reproducing itself, and then refuelling the copy and travelling on, by any conceivable mechanical method surely we'd notice the environmental impact. The construction infrastructure made by the replicating probe would remain, or the mined out moon we would have noticed. Otherwise the machine would have to be unnecessarily efficient. If such a device arrived now, and starting to trying to replicate itself it would represent an obvious industrial project on a scale beyond that which we are capable.

    such a self-replicating probe strategy may be effectively similar a berserker strategy... does the probe ask permission to start exploiting the resources of an alien solar system?

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    Quote Originally Posted by A.DIM View Post
    ...that lack of serious consideration for such self replicating probes has left a gap in our SETI investigations.
    ...only if you assume that these probes actually exist. If not, no "gap".
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by transreality View Post
    If an alien space ship capable of travelling here, reproducing itself, and then refuelling the copy and travelling on, by any conceivable mechanical method surely we'd notice the environmental impact.
    Naw....these "probes" are all "sneaky" and stuff.
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by transreality View Post
    If an alien space ship capable of travelling here, reproducing itself, and then refuelling the copy and travelling on, by any conceivable mechanical method surely we'd notice the environmental impact. The construction infrastructure made by the replicating probe would remain, or the mined out moon we would have noticed. Otherwise the machine would have to be unnecessarily efficient. If such a device arrived now, and starting to trying to replicate itself it would represent an obvious industrial project on a scale beyond that which we are capable.

    such a self-replicating probe strategy may be effectively similar a berserker strategy... does the probe ask permission to start exploiting the resources of an alien solar system?
    I think you are assuming said SRP would do things on a large scale and make zillions of copies, however I don't think this is a foregone conclusion. I think its plausible that the probe could make say a hundred copies of itself from asteroid material and we would never ever notice, then send off 90 of its copies to the next star systems. The remaining 10 could then just recon the system for things that would be interesting to the makers, say life habitats or something. I dont think we would notice them unless they were programmed to become noticed.

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    Presumably a SRP would not only collect information, but also send that information back to its originating system, wherever that may be. Perhaps the most obvious signature of a SR in our system would be the transmitter it would build to send this data back, and possibly the receiver it would build to recieve new orders. On the other hand if the home system is transmitting new orders, then we might have a chance of intercepting the inwards transmission ourselves.

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    Quote Originally Posted by iquestor View Post
    A Very interesting paper. Not sure I agree with searching for ET in other Galaxies though. Like the idea of searching for SRP's in the solar system which seems somewhat plausible.
    Heh, I agree.
    SETI conducts its searches at galactic distances; Perhaps it should be listening closer to home.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    Quote Originally Posted by transreality View Post
    If an alien space ship capable of travelling here, reproducing itself, and then refuelling the copy and travelling on, by any conceivable mechanical method surely we'd notice the environmental impact. The construction infrastructure made by the replicating probe would remain, or the mined out moon we would have noticed. Otherwise the machine would have to be unnecessarily efficient. If such a device arrived now, and starting to trying to replicate itself it would represent an obvious industrial project on a scale beyond that which we are capable.
    I suspect any ETi capable of sending out SRPs is thousands and more years beyond what we’re capable of, let alone what we might conceive.
    I can agree though, it seems we might’ve discovered something about them, if not the probes themselves (or eburacum’s transmitters/receivers), even while I don’t think we’ve come close to thoroughly exploring our own system.
    But as Wiley points out: ”When we populate the equation with the lower and upper estimates, it yields Nr = 10^2–10^11 SRPs in our solar system at this very moment. The absurdity of this result underlies the tremendous burden of the Fermi Paradox and demonstrates why many ETI-hopefuls have shied away from even the remotest consideration of SRPs.”
    That’s a lot of probes we’ve yet to discover!

    such a self-replicating probe strategy may be effectively similar a berserker strategy... does the probe ask permission to start exploiting the resources of an alien solar system?
    Yes, Wiley discusses the “voluntary refrainment” argument and berserkers potential, but counters it with the “worldwide undetected-uncorrected-RAM-bit-error rate (being) negligible,” which shows our machines by and large do what we program them to do. Is there something what precludes some advanced ETi from achieving such engineering and data integrity? I wouldn’t think so.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    Thanks for the link to this paper. I need to write a similar paper to model the effects of competing war machines--all originating from the same place in the galaxy, on the assumption that they're primarily designed by competing factions of the same species.

    The discussion of potential predator-prey relationships is fun speculation, but I find it more plausible for machines to be specifically designed to destroy others rather than to spontaneously mutate into predators.

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    Quote Originally Posted by A.DIM View Post
    SETI conducts its searches at galactic distances...
    Please cite the SETI page where it talks of searches in other galaxies.

    Perhaps it should be listening closer to home.
    Please present your reasoning to believe that SETI is not listening closer than galactic distances.
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by eburacum45 View Post
    Presumably a SRP would not only collect information, but also send that information back to its originating system, wherever that may be. Perhaps the most obvious signature of a SR in our system would be the transmitter it would build to send this data back, and possibly the receiver it would build to recieve new orders. On the other hand if the home system is transmitting new orders, then we might have a chance of intercepting the inwards transmission ourselves.
    Thats a good point, if even a hundred were being built per visited star then every star would have multiple transmitters sending data home; surely something would show up on SETI searches.

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    Quote Originally Posted by transreality View Post
    ... surely something would show up ...
    I'd go with "maybe something would show up". If the probes are nanotech, and the signals are highly directional (i.e. laser) packets sent once in a while from a KBO or Neptune trojan, how would we see it?
    Forming opinions as we speak

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    Maybe the probes are invisible, and that's why we don't see them.
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by R.A.F. View Post
    Please cite the SETI page where it talks of searches in other galaxies.

    Please present your reasoning to believe that SETI is not listening closer than galactic distances.
    Although I think anyone who read the paper understood what I was saying, apologies it wasn’t clear to you. Divided into ranges of distance -solar system, Milky Way, Universe- SETI searches are listening primarily at galactic distances, limited to the MW. By and large they’re not listening for things within our solar system, nor are they listening for extragalactic sources (though a few have).
    The “Search Archive” at the SETI institute gives every search conducted since 1960, providing resolution, frequency and objects searched. By this, I think there’s good reason to think SETI searches within our solar system (closer to home) are near nonexistent.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    Quote Originally Posted by transreality View Post
    If an alien space ship capable of travelling here, reproducing itself, and then refuelling the copy and travelling on, by any conceivable mechanical method surely we'd notice the environmental impact. The construction infrastructure made by the replicating probe would remain, or the mined out moon we would have noticed. Otherwise the machine would have to be unnecessarily efficient. If such a device arrived now, and starting to trying to replicate itself it would represent an obvious industrial project on a scale beyond that which we are capable.
    I am not at all sure we would recognize a "mined out moon" for what it is. There are many moons in the Solar System with features we simply cannot explain, but natural assumption in the minds of planetary scientists is to come up with "natural" theories.

    Does this look mined out to you?

    http://www.nasa.gov/images/content/1...e_749_ys_4.jpg

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    Quote Originally Posted by Ilya View Post
    I am not at all sure we would recognize a "mined out moon" for what it is. There are many moons in the Solar System with features we simply cannot explain, but natural assumption in the minds of planetary scientists is to come up with "natural" theories.

    Does this look mined out to you?

    http://www.nasa.gov/images/content/1...e_749_ys_4.jpg
    It most certainly does.
    Good point.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    Quote Originally Posted by A.DIM View Post
    Although I think anyone who read the paper understood what I was saying, apologies it wasn’t clear to you.
    Why that is about the most "polite" insult I have ever received.

    I think there’s good reason to think SETI searches within our solar system (closer to home) are near nonexistent.
    Why would SETI (which is primarily a radio search) search within our Solar System?...what would they search "for"?...and if they are not searching for radio transmissions, then by what method would this search within the SS be conducted?
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by Ilya View Post
    Does this look mined out to you?
    No, it looks like it has been bombarded over billions of years.


    It is a shame we don't "do" science by how something looks, but by evidence...
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by transreality View Post
    If an alien space ship capable of travelling here, reproducing itself, and then refuelling the copy and travelling on, by any conceivable mechanical method surely we'd notice the environmental impact. The construction infrastructure made by the replicating probe would remain, or the mined out moon we would have noticed. Otherwise the machine would have to be unnecessarily efficient.
    Along with Ilya's note, it's also not clear that a machine leaving no traces would be unnecessarily efficient. Two potential uses for arbitrary "waste" matter are reaction mass and impact/radiation shielding. Because the exact content of the matter used is not important, what would otherwise be waste matter is actually useful.

    As a result, the most natural thing could be to consume an entire comet/moon/asteroid, leaving nothing behind. It's not unnecessarily efficient to use "waste" matter for reaction mass. Putting it into the exhaust stream increases drive performance and efficiency compared to dumping it overboard or leaving it behind.

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    Quote Originally Posted by R.A.F. View Post
    Why that is about the most "polite" insult I have ever received.
    Why should you be insulted? You didn't read the paper, did you?

    Why would SETI (which is primarily a radio search) search within our Solar System?...what would they search "for"?...and if they are not searching for radio transmissions, then by what method would this search within the SS be conducted?
    SETI is the search for extraterrestrial intelligence. It should not be limited to radio from faraway places. I expect by now, you know the almost nil odds for detecting ETi by radio transmission. And as the paper in question discusses, there's good reason to consider SRPs as plausible alternative. SETI should consider other possibilities and methods for research.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    Quote Originally Posted by IsaacKuo View Post
    Along with Ilya's note, it's also not clear that a machine leaving no traces would be unnecessarily efficient. Two potential uses for arbitrary "waste" matter are reaction mass and impact/radiation shielding. Because the exact content of the matter used is not important, what would otherwise be waste matter is actually useful.

    As a result, the most natural thing could be to consume an entire comet/moon/asteroid, leaving nothing behind. It's not unnecessarily efficient to use "waste" matter for reaction mass. Putting it into the exhaust stream increases drive performance and efficiency compared to dumping it overboard or leaving it behind.
    Most natural is to efficiently extract the precious elements and leave the rest in an expanding debris cloud, some of which may land on various potentially or actually inhabited worlds of the system. Why would they hoover up all the left over dust and carry the junk around the galaxy with them, it all requires fuel to move. Carrying inert matter and dumping in the exhaust stream; i'm not sure that works not even considering the cost of collecting it, and a self-replicating probe could repair itself faster that the incoming cosmic ray damage so carrying a massive shield of arbitary size made of indigestible dust doesn't seem useful.

    the only reason to be 100% efficient is be conveniently invisible to the locals forever.

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    Quote Originally Posted by transreality View Post
    Most natural is to efficiently extract the precious elements and leave the rest in an expanding debris cloud, some of which may land on various potentially or actually inhabited worlds of the system. Why would they hoover up all the left over dust and carry the junk around the galaxy with them, it all requires fuel to move.
    Because they hoover up all the left over dust and don't carry it all with them. Instead, they use it mostly for reaction mass.

    Anyway, a debris cloud would not last very long. Sunlight pressure would eliminate it on short timescales.

    And so what if there are random pieces of larger waste debris, which are big enough to survive Earth's atmosphere? How would it look any different from any other meteorite? It's just waste matter.
    Carrying inert matter and dumping in the exhaust stream; i'm not sure that works not even considering the cost of collecting it,
    It works great. The marginal cost of collecting waste material is almost nothing, since you needed to sift through it to get at the "good stuff" anyway. The energy and power requirements for propulsion go down proportionately with the reaction mass used, so the more mass the better.
    and a self-replicating probe could repair itself faster that the incoming cosmic ray damage so carrying a massive shield of arbitary size made of indigestible dust doesn't seem useful.
    A self replicating probe may not necessarily have any self repair capability. It may be simpler and safer to simply self-terminate on errors to eliminate the possibility of mutation. After all, the good copies can recycle self-terminated probes into fresh copies.

    Either way, self repair or replacement only work when power is available. When trekking across interstellar space, there's no solar power. A reasonable solution could be to shut down all systems during the journey, and to only revive when sunlight at the destination system thaws the probes out of hibernation mode.

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    Quote Originally Posted by A.DIM View Post
    Why should you be insulted?
    Just because someone doesn't agree with you doesn't mean they don't understand...the implication that it must be "my fault" is rather insulting...

    SETI is the search for extraterrestrial intelligence. It should not be limited to radio from faraway places.
    I'm sorry, but that's not your "call" to make.

    I expect by now, you know the almost nil odds for detecting ETi by radio transmission.
    I don't play odds.

    ...as the paper in question discusses, there's good reason to consider SRPs as plausible alternative.
    There's no reason to think that...wishful thinking does not qualify as evidence.

    SETI should consider other possibilities and methods for research.
    Like what?? Investigating flying saucer stories?...crop circles?...imaginary probes?


    What SETI does is a proper scientific investigation...what you propose is not...
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Quote Originally Posted by R.A.F. View Post
    Just because someone doesn't agree with you doesn't mean they don't understand...the implication that it must be "my fault" is rather insulting...
    It's not a matter of you not agreeing with me, rather it's that you didn't read the paper (you obviously didn't answer that question for a reason) and thus didn't understand what I was saying. Who's fault should it be?
    Frankly, I'm insulted every time you post in one of my threads when clearly you don't read the material I present.

    Otherwise, we might get more insightful posts from you than ....

    I'm sorry, but that's not your "call" to make.

    I don't play odds.

    There's no reason to think that...wishful thinking does not qualify as evidence.

    Like what?? Investigating flying saucer stories?...crop circles?...imaginary probes?

    What SETI does is a proper scientific investigation...what you propose is not...
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

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    Well, I have read the paper, and perhaps the most interesting concept in it is that of the Interstellar Transportation Bandwidth. They suggest that individual colonies will be insulated from each other by the high cost of interstellar transportation, so that a colony which experiences high population pressure or resource depletion would not be able to export its problems to the next system, and so cannot cause a population explosion throughout the galaxy. This is an optimistic view, and allows a galaxy to have a number of moderately successful and sustainable colonies, even if some of those colonies individually experience high population growth and resource depletion.

    I'm not entirely sure that the interstellar transportation bandswidth is quite as low as they calculate, however; a solar system which dedicated all available mass and energy to sending colonists to neighboring systems could flood those systems with arriving spacecraft. Wiley suggests that incoming colonists would probably be welcomed, for humanitarian reasons at the very least, after their long and arduous voyage. I suspect that there would be considerable amounts of data traffic too, sentient programs beaming themselves from star to star looking to increase the amount of available processing power.

    Perhaps the inhabitants of a small, comfortable, sustainable colony might find themselves bombarded by colonists arriving in beam-propelled ships, and by artificial mind programs looking for substrates to run on. These small, easily sustainable colonies might not remain cosy backwaters for very long if their neighbors are densely populated and highly expansive.

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    Quote Originally Posted by eburacum45 View Post
    I suspect that there would be considerable amounts of data traffic too, sentient programs beaming themselves from star to star looking to increase the amount of available processing power.
    Interesting concept. I'm just thinking that there will have to be some kind of universal computer/ information processing protocol, but what would that be?

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    Why the assumption that if probes are in our system, they'll be easy to identify and find? First and foremost, if you're worried about more primitive societies finding your probe and getting all freaked out about it, then you're going to want your probes to be very hard to detect. Given that we're now discovering that Star Trek like cloaking technology might be possible, any society which is 100+ more years advanced than we are, is going to be much better at hiding their stuff than we are at finding it. This desire to hide the probes is even greater if, like Hawking, you assume that there's a good chance you'll run into a hostile species. The last thing you want to do is give them a hint as to what your technology is like.

    Then there's our ability to identify advanced technology were we to see it. What will a radio transmitter look like 100 years from now? It would be interesting to ask Edison, Marconi, and Tesla in 1911 what they thought radios would look like in 2011. I doubt if any of them could imagine a radio unit as small as that which fits in a typical smartphone, nor do I think that they could even guess at the capabilities of what a smartphone could do. If Kurtzweil's estimates of what technology will be like in 100 years are right, then our ability to predict, and thus identify, alien technology is going to be pretty limited.

    Finally, there's a design aesthetic which goes into everything at a basic level, so deeply entwined with who we are as a species that it could make recognizing elements of alien technology difficult for us. We tend to prefer certain shapes at certain ratios for our designs, aliens may not necessarily prefer those same shapes or ratios.

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    Quote Originally Posted by A.DIM View Post
    ...rather it's that you didn't read the paper (you obviously didn't answer that question for a reason) and thus didn't understand what I was saying. Who's fault should it be?
    Of course I read the paper...man you are becoming so predictable...

    ...I'm insulted every time you post in one of my threads when clearly you don't read the material I present.
    "Clearly?"...because my opinion is to disagree with what a paper says, I MUST NOT HAVE READ IT?

    ...we might get more insightful posts from you than ....

    Everyone take notice...this is the "thanks" I get for agreeing with A.DIM...I shouldn't have gone against my nature, and simply have disagreed...



    ...and if it wasn't obvious, I am so out of this thread...
    Last edited by R.A.F.; 2011-Dec-03 at 05:37 PM. Reason: added "?", and "the"
    The facts, gentlemen, and nothing but the facts, for careful eyes are narrowly watching. Isaac Asimov

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    Seems to me there are far better ways to look for intelligent life than looking for probes that could be any size at any place in any number that may or not be trying to purposefully disguise themselves. Using a very limited range of measure to look at a whole has never stopped SETI though. I would imagine their results would mirror those results from current extremely limited searches.

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