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> It's never aliens. Why? Shouldn't probes be here by now? There are 200 sextillion stars in the observable universe. We know of one civilization--ours, and i

by ericb 2y ago

> It's never aliens. Why? Shouldn't probes be here by now? There are 200 sextillion stars in the observable universe. We know of one civilization--ours, and it immediately began sending probes once capable. If Von Neumann self-replicating probes are possible, doesn't that solve both distance/speed of light/time scale objection and imply probes should be here by now? The sending civilization may not even still exist, but their probes would.

knowitnone 2y ago
Why not? Yes, we did send out probes...and where are we with them? "If Von Neumann self-replicating probes are possible" That's a big if. Where is proof of these probes that you speak of?
- nadermx 2y ago
  Thats also assuming Von Neumann probes don't replicate wrong like DNA as it clones, etc. Too many variables for it too be feasible
  - alganet 2y ago
    Why do you assume DNA replication is "wrong"? Maybe it's just part of the exploring. It needs to adapt to new environments to explore them after all.
  - ericb 2y ago
    If I could attach a software program to every replicating chunk of DNA, I'm pretty sure I could write a checksum and diagnostic and instructions to shut down if they failed. That's not a variable that does anything to feasibility.
    - krapp 2y ago
      What would this "software program" be made of? Millions of years of evolution have already granted DNA the capacity for diagnostics, error correction and self-repair. Despite that, genetic replication is still error prone, and everything still fails, sometimes catastrophically. DNA is made of molecular bonds, and that "software" is necessarily also made of molecular bonds, there is no distinction between "software" and "hardware" at that level of physical granularity. You're not going to get perfect replication of anything over millions of generations. That violates the laws of thermodynamics. The system has to change, randomly and unexpectedly, and it has to fail over time. Entropy must accumulate. And that's not even taking into account the radioactive hellscape of interstellar space. This is the difference between mathematics and physics. Mathematicians can handwave away or ignore inconvenient or uninteresting complexities, and thus something like the infinite exponential progress of self-replicating probes across the galaxy seems obvious because the math is obvious, but reality doesn't allow that.
      - ericb 2y ago
        > The system has to change, randomly and unexpectedly. Entropy must accumulate. Yes to the first two, but "has to fail over time" is something you are making up--not a law of physics. Local decreases of entropy happen continually. Resilient, error-checking, self-healing systems are possible.
        krapp 2y ago
        Self-replicating probes aren't closed systems. They exist within the universe, consume matter (which is how they replicate) and emit waste heat (as all physical systems must,) and are bound to the laws of physics which, yes, include the second law of thermodynamics. There may be short term local reductions in entropy, but eventually, inevitably, entropy must increase. >Resilient, error-checking, self-healing systems are possible. You cannot have such systems be perfectly efficient. That isn't physics, it's magic.
        ericb 2y ago
        No one suggested perfect efficiency. I'm debating with you, a product of a similar reproductive process (evolution) where a system of throwing away the bad offspring has worked just fine. Magical indeed!
        ben_w 2y ago
        In fairness, that's a bad argument because this same process also gives us cancer. I'd instead point out that while "perfect" isn't possible, we can relatively simply design the system to have an error rate such that there's less than a 1e-12 chance of an error occurring anywhere in the universe even if you did turn the entire mass of the universe into probes. I'd counter that with the point that people are very bad at accounting for all the possible ways that systems can fail, and that while it's easy to create an error correction code that good, the actual failure rate of the system as a whole is likely to be much, much worse.
        2y ago
- NoMoreNicksLeft 2y ago
  > That's a big if. That's a tiny "if". Were you to ask me to write a science fiction story where the premise was that they were indeed impossible, I'd struggle to come up with ideas why that might be the case. In principle it must remain true, even if the "self-replicating probe" were gigantic human colony ships, and humans were some kind of component of the scheme. And if humans are sufficient components to make that work, why not something simpler than a big drooling man-monkey? It's not that they're impossible. I don't think we'd need even another 200 years to do it. I just don't think we have the time. We're on a fast course to extinction, and by the time most people realize that this is so, the last chance to avert it will be 30 or 40 years in the rear-view.
- ericb 2y ago
  > That's a big if. Is it? Since humans can send probes, and reproduce ourselves, technology and civilization, it proves that a slower self-replicating bio-mechanical system has this capability and now we're left debating if a faster more compact system is possible, which doesn't seem like a leap?
  - krapp 2y ago
    It is a leap. Human beings are dependent on a specific, very delicate ecosystem and technological civilization to be able to replicate with the stability and scale that we do. We also can't replicate ourselves using arbitrary matter, we require the presence of a diverse breeding population. You can't just take human beings, push them out into space and expect them - somehow - to multiply exponentially and without error using any arbitrary matter they encounter over millions of generations, but that's the baseline expectation of Von Neumann probes. Add to that all of the assumptions required to use Von Neumann probes as an explanation for modern UFO folklore. One might assume that a simplistic organism could survive and thrive more easily in interstellar space (something like a virus or tardigrade, for example.) Complex organisms tend to be more delicate and more prone to replication errors over time, as well as more sensitive to things like the radiation of interstellar space. But that isn't what people are reporting - they're reporting large, complex, technological, apparently even piloted vehicles. And that's not even getting into the interdimensional stuff, links between UFOs and the supernatural, or abductions. Obviously Von Neumann probes haven't consumed the galaxy. Therefore, either no technological civilization has ever existed in the universe other than ourselves, in which case UFOs/UAPs cannot be Von Neumann probes because they obviously haven't consumed the galaxy, and don't behave in the ways that such probes would be expected to, or else technological civilizations can and likely do exist, and Von Neumann probes aren't as simple or inevitable as people seem to think. And it still doesn't explain UFOs/UAPs as reported.
    - ericb 2y ago
      > haven't consumed the galaxy That's absurd. If you can make a self-replicating probe, you can code a heuristic that prevents a grey goo scenario. Cells reproduce, but they haven't consumed the galaxy. > doesn't explain UFOs/UAPs as reported. So, the existence of spurious reports magically invalidates actual probes?
holoduke 2y ago
Assuming they all can travel near light speed and considering time dilation, all interstellar civilizations will meet each other "from our perspective" somewhere a trillion years from now.
- more_corn 2y ago
  This statement is so nonsensical I’m not even going to respond to the content.
  - holoduke 2y ago
    Please do.
TeMPOraL 2y ago
> If Von Neumann self-replicating probes are possible, doesn't that solve both distance/speed of light/time scale objection and imply probes should be here by now? We should've been seeing progressively more of them then, perhaps already been eaten by them.
- pfdietz 2y ago
  Earth should have been eaten by them billions of years ago.
  - ben_w 2y ago
    It was, and we are the goo. Though if you mean "physically disassemble the Earth", conditional on us having not noticed them yet, there's this: https://arxiv.org/pdf/2102.01522 https://arxiv.org/pdf/2102.01522
browningstreet 2y ago
> We know of one civilization--ours Strong argument, no notes.
- more_corn 2y ago
  The argument that we have evidence of our own civilization requires no evidence. You’re typing on an artifact of that civilization. An argument that there exists any other civilization requires evidence. Show me yours.
  - browningstreet 2y ago
    We agree.
alganet 2y ago
The odds definitely tell us that by now, we should be seen a vast swarm of Von Neumann self-replicating little machines all around us. I stand by those odds, that idea makes a lot of sense. However, "Von-Neumman probes must exist if possible" is a very different statement from "UAPs are alien probes".
- bitcharmer 2y ago
  [dead]
eddyg 2y ago
> Why? Shouldn't probes be here by now? The Great Filter is one possible explanation: https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter https://www.youtube.com/watch?v=TrGpG0OrNws https://www.youtube.com/watch?v=TrGpG0OrNws
tiahura 2y ago
So advanced civilizations routinely: FTL to earth, fly around San Diego buzzing the navy, then head to the southwest where they have engine trouble and crash? Seems likely.
- NoMoreNicksLeft 2y ago
  This posits an extraordinarily American attitude to the cosmos. The universe eschewed public transportation several billion years ago, and instead of building the space subway system, they all got personal flying saucers. So yes they're out there on the weekends, cruising around and causing mischief. Even drunk-piloting their starships into sheep ranches in New Mexico (do the assholes even have insurance?). Had space politics gone differently, there would be high-speed galaxy trains connecting all the important star systems, and we would've gone unnoticed in our little backwater forever. You need proof? r/fuckpersonalflyingsaucers is marked "invite only".
- ericb 2y ago
  It doesn't seem like you read my full comment?
  - dwaltrip 2y ago
    The probes can’t be both so incompetent that they can’t avoid detection and competent enough to successfully fly thousands of light years over god knows how much time.
    - astronads 2y ago
      You’re making some assumptions here and I suggest you broaden your mindset a bit. First of all, at least according to testimony under oath, they are not avoiding detection and there is a plethora of high resolution imagery and sensor data, they just keep it hidden and highly classified. I get that there isn’t a lot of quality stuff coming from civilians, but we don’t know the UAP intentions or quantity. They could be just trying to observe us without freaking us out or interfering with us en masse, much like we observe animals in nature ourselves. They may only be interested in subtly monitoring our military assets and nothing else. There could be any other unknowable reasons. They may not perceive existence the same way as us, they may not have the same 5 senses or see in the same spectrums, they may not have emotions or a completely different thought process. They also may not be light years away, but rather ultra terrestrial or interdimensional or time travelers or they use wormholes to “teleport”. We just don’t know, but the possibilities are not constrained to just your “incompetent but competent” paradox. Edit: you may find this article thought provoking: https://jdmadden.substack.com/p/naturalizing-without-demythologizing https://jdmadden.substack.com/p/naturalizing-without-demytho...
fsckboy 2y ago
> Why? Shouldn't probes be here by now? it's going to turn out that absence of evidence is evidence of absence
kcplate 2y ago
We know of only one planet with life. Of which there are estimates of forms of life number in the billions to possibly a trillion since the formation of our planet. One and only one form of life has evolved the intelligence to even as the question or conceptualize existence beyond this world and it took literally over a third of the age of the universe for us to get this far and short of sending machines beyond this planet, we (the living things) haven’t ventured much further than our own moon. So…yes, until we see some tentacled slug monster land in Central Park…or their probe, I am going to assume that intelligent life is super rare. Lots and lots of time must pass to become intelligent and advanced enough to venture beyond the place where they live out there. Also, distances are so vast between these intelligent civilizations that there just hasn’t been enough time that has passed for them or their probes to reach us since the creation of the universe.
ben_w 2y ago
If you make reasonable assumptions about grabby aliens (the kind that wants to do VN probes and get here anyway), and condition on us having not yet noticed, then the current modelling suggests about 40-50% of the universe has already been occupied by them — the only reason we wouldn't have noticed is that light from the expansion just hasn't reached us yet. https://arxiv.org/pdf/2102.01522 https://arxiv.org/pdf/2102.01522

by ericb 2y ago

knowitnone 2y ago

Why not? Yes, we did send out probes...and where are we with them? "If Von Neumann self-replicating probes are possible" That's a big if. Where is proof of these probes that you speak of?

nadermx 2y ago
Thats also assuming Von Neumann probes don't replicate wrong like DNA as it clones, etc. Too many variables for it too be feasible
- alganet 2y ago
  Why do you assume DNA replication is "wrong"? Maybe it's just part of the exploring. It needs to adapt to new environments to explore them after all.
- ericb 2y ago
  If I could attach a software program to every replicating chunk of DNA, I'm pretty sure I could write a checksum and diagnostic and instructions to shut down if they failed. That's not a variable that does anything to feasibility.
  - krapp 2y ago
    What would this "software program" be made of? Millions of years of evolution have already granted DNA the capacity for diagnostics, error correction and self-repair. Despite that, genetic replication is still error prone, and everything still fails, sometimes catastrophically. DNA is made of molecular bonds, and that "software" is necessarily also made of molecular bonds, there is no distinction between "software" and "hardware" at that level of physical granularity. You're not going to get perfect replication of anything over millions of generations. That violates the laws of thermodynamics. The system has to change, randomly and unexpectedly, and it has to fail over time. Entropy must accumulate. And that's not even taking into account the radioactive hellscape of interstellar space. This is the difference between mathematics and physics. Mathematicians can handwave away or ignore inconvenient or uninteresting complexities, and thus something like the infinite exponential progress of self-replicating probes across the galaxy seems obvious because the math is obvious, but reality doesn't allow that.
    - ericb 2y ago
      > The system has to change, randomly and unexpectedly. Entropy must accumulate. Yes to the first two, but "has to fail over time" is something you are making up--not a law of physics. Local decreases of entropy happen continually. Resilient, error-checking, self-healing systems are possible.
      - krapp 2y ago
        Self-replicating probes aren't closed systems. They exist within the universe, consume matter (which is how they replicate) and emit waste heat (as all physical systems must,) and are bound to the laws of physics which, yes, include the second law of thermodynamics. There may be short term local reductions in entropy, but eventually, inevitably, entropy must increase. >Resilient, error-checking, self-healing systems are possible. You cannot have such systems be perfectly efficient. That isn't physics, it's magic.
        ericb 2y ago
        No one suggested perfect efficiency. I'm debating with you, a product of a similar reproductive process (evolution) where a system of throwing away the bad offspring has worked just fine. Magical indeed!
        ben_w 2y ago
        In fairness, that's a bad argument because this same process also gives us cancer. I'd instead point out that while "perfect" isn't possible, we can relatively simply design the system to have an error rate such that there's less than a 1e-12 chance of an error occurring anywhere in the universe even if you did turn the entire mass of the universe into probes. I'd counter that with the point that people are very bad at accounting for all the possible ways that systems can fail, and that while it's easy to create an error correction code that good, the actual failure rate of the system as a whole is likely to be much, much worse.
        2y ago
NoMoreNicksLeft 2y ago
> That's a big if. That's a tiny "if". Were you to ask me to write a science fiction story where the premise was that they were indeed impossible, I'd struggle to come up with ideas why that might be the case. In principle it must remain true, even if the "self-replicating probe" were gigantic human colony ships, and humans were some kind of component of the scheme. And if humans are sufficient components to make that work, why not something simpler than a big drooling man-monkey? It's not that they're impossible. I don't think we'd need even another 200 years to do it. I just don't think we have the time. We're on a fast course to extinction, and by the time most people realize that this is so, the last chance to avert it will be 30 or 40 years in the rear-view.
ericb 2y ago
> That's a big if. Is it? Since humans can send probes, and reproduce ourselves, technology and civilization, it proves that a slower self-replicating bio-mechanical system has this capability and now we're left debating if a faster more compact system is possible, which doesn't seem like a leap?
- krapp 2y ago
  It is a leap. Human beings are dependent on a specific, very delicate ecosystem and technological civilization to be able to replicate with the stability and scale that we do. We also can't replicate ourselves using arbitrary matter, we require the presence of a diverse breeding population. You can't just take human beings, push them out into space and expect them - somehow - to multiply exponentially and without error using any arbitrary matter they encounter over millions of generations, but that's the baseline expectation of Von Neumann probes. Add to that all of the assumptions required to use Von Neumann probes as an explanation for modern UFO folklore. One might assume that a simplistic organism could survive and thrive more easily in interstellar space (something like a virus or tardigrade, for example.) Complex organisms tend to be more delicate and more prone to replication errors over time, as well as more sensitive to things like the radiation of interstellar space. But that isn't what people are reporting - they're reporting large, complex, technological, apparently even piloted vehicles. And that's not even getting into the interdimensional stuff, links between UFOs and the supernatural, or abductions. Obviously Von Neumann probes haven't consumed the galaxy. Therefore, either no technological civilization has ever existed in the universe other than ourselves, in which case UFOs/UAPs cannot be Von Neumann probes because they obviously haven't consumed the galaxy, and don't behave in the ways that such probes would be expected to, or else technological civilizations can and likely do exist, and Von Neumann probes aren't as simple or inevitable as people seem to think. And it still doesn't explain UFOs/UAPs as reported.
  - ericb 2y ago
    > haven't consumed the galaxy That's absurd. If you can make a self-replicating probe, you can code a heuristic that prevents a grey goo scenario. Cells reproduce, but they haven't consumed the galaxy. > doesn't explain UFOs/UAPs as reported. So, the existence of spurious reports magically invalidates actual probes?

holoduke 2y ago

Assuming they all can travel near light speed and considering time dilation, all interstellar civilizations will meet each other "from our perspective" somewhere a trillion years from now.

more_corn 2y ago
This statement is so nonsensical I’m not even going to respond to the content.
- holoduke 2y ago
  Please do.

TeMPOraL 2y ago

> If Von Neumann self-replicating probes are possible, doesn't that solve both distance/speed of light/time scale objection and imply probes should be here by now? We should've been seeing progressively more of them then, perhaps already been eaten by them.

pfdietz 2y ago
Earth should have been eaten by them billions of years ago.
- ben_w 2y ago
  It was, and we are the goo. Though if you mean "physically disassemble the Earth", conditional on us having not noticed them yet, there's this: https://arxiv.org/pdf/2102.01522 https://arxiv.org/pdf/2102.01522

browningstreet 2y ago

> We know of one civilization--ours Strong argument, no notes.

more_corn 2y ago
The argument that we have evidence of our own civilization requires no evidence. You’re typing on an artifact of that civilization. An argument that there exists any other civilization requires evidence. Show me yours.
- browningstreet 2y ago
  We agree.

alganet 2y ago

The odds definitely tell us that by now, we should be seen a vast swarm of Von Neumann self-replicating little machines all around us. I stand by those odds, that idea makes a lot of sense. However, "Von-Neumman probes must exist if possible" is a very different statement from "UAPs are alien probes".

bitcharmer 2y ago
[dead]

eddyg 2y ago

> Why? Shouldn't probes be here by now? The Great Filter is one possible explanation: https://en.wikipedia.org/wiki/Great_Filter https://en.wikipedia.org/wiki/Great_Filter https://www.youtube.com/watch?v=TrGpG0OrNws https://www.youtube.com/watch?v=TrGpG0OrNws

tiahura 2y ago

So advanced civilizations routinely: FTL to earth, fly around San Diego buzzing the navy, then head to the southwest where they have engine trouble and crash? Seems likely.

NoMoreNicksLeft 2y ago
This posits an extraordinarily American attitude to the cosmos. The universe eschewed public transportation several billion years ago, and instead of building the space subway system, they all got personal flying saucers. So yes they're out there on the weekends, cruising around and causing mischief. Even drunk-piloting their starships into sheep ranches in New Mexico (do the assholes even have insurance?). Had space politics gone differently, there would be high-speed galaxy trains connecting all the important star systems, and we would've gone unnoticed in our little backwater forever. You need proof? r/fuckpersonalflyingsaucers is marked "invite only".
ericb 2y ago
It doesn't seem like you read my full comment?
- dwaltrip 2y ago
  The probes can’t be both so incompetent that they can’t avoid detection and competent enough to successfully fly thousands of light years over god knows how much time.
  - astronads 2y ago
    You’re making some assumptions here and I suggest you broaden your mindset a bit. First of all, at least according to testimony under oath, they are not avoiding detection and there is a plethora of high resolution imagery and sensor data, they just keep it hidden and highly classified. I get that there isn’t a lot of quality stuff coming from civilians, but we don’t know the UAP intentions or quantity. They could be just trying to observe us without freaking us out or interfering with us en masse, much like we observe animals in nature ourselves. They may only be interested in subtly monitoring our military assets and nothing else. There could be any other unknowable reasons. They may not perceive existence the same way as us, they may not have the same 5 senses or see in the same spectrums, they may not have emotions or a completely different thought process. They also may not be light years away, but rather ultra terrestrial or interdimensional or time travelers or they use wormholes to “teleport”. We just don’t know, but the possibilities are not constrained to just your “incompetent but competent” paradox. Edit: you may find this article thought provoking: https://jdmadden.substack.com/p/naturalizing-without-demythologizing https://jdmadden.substack.com/p/naturalizing-without-demytho...

fsckboy 2y ago

> Why? Shouldn't probes be here by now? it's going to turn out that absence of evidence is evidence of absence

kcplate 2y ago

We know of only one planet with life. Of which there are estimates of forms of life number in the billions to possibly a trillion since the formation of our planet. One and only one form of life has evolved the intelligence to even as the question or conceptualize existence beyond this world and it took literally over a third of the age of the universe for us to get this far and short of sending machines beyond this planet, we (the living things) haven’t ventured much further than our own moon. So…yes, until we see some tentacled slug monster land in Central Park…or their probe, I am going to assume that intelligent life is super rare. Lots and lots of time must pass to become intelligent and advanced enough to venture beyond the place where they live out there. Also, distances are so vast between these intelligent civilizations that there just hasn’t been enough time that has passed for them or their probes to reach us since the creation of the universe.

ben_w 2y ago

If you make reasonable assumptions about grabby aliens (the kind that wants to do VN probes and get here anyway), and condition on us having not yet noticed, then the current modelling suggests about 40-50% of the universe has already been occupied by them — the only reason we wouldn't have noticed is that light from the expansion just hasn't reached us yet. https://arxiv.org/pdf/2102.01522 https://arxiv.org/pdf/2102.01522