Page 25 of 28 FirstFirst ... 152324252627 ... LastLast
Results 721 to 750 of 816

Thread: What do you think is the most likely explanation for the Fermi paradox?

  1. #721
    Join Date
    Mar 2004
    Posts
    18,680
    Quote Originally Posted by Noclevername View Post
    OK, abstracts, but I want the meat.

    What does the overall weight of evidence say? You invoked statistics, so let's do some. What are the numbers? I feel like I'm getting nowhere with this discussion.
    I don’t see where it would be useful. The key advance in relevant knowledge since the debate started is that we now have some rough idea how many terrestrial planets are in the galaxy. We still can’t say anything useful about how many would develop life and how many would develop species that could build technological societies similar to ours. And of those, we can’t say how long the species and technological civilization would last, or if they would ever develop star travel, or ever become fanatic expansionists.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  2. #722
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Van Rijn View Post
    I don’t think “mainstream” is a very useful term in this context, given that it is speculation layered on assumptions. Yes, there are some common lines of speculation, but it appears to be more based on personal preferences and biases that anything else, and it is always easy to say “But ...” Even restricting speculation to known physics may be more game playing than useful here. Who can say if new physics or new observations might lead civilizations to do more interesting things than interstellar expansion?
    I think that belongs in the "transcendent" category of explanations.

    Possibly, at a level of development not much better than ourselves, every intelligent species finds out something game-changing about the nature of life, the universe and everything.

  3. #723
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Noclevername View Post
    OK, abstracts, but I want the meat.

    What does the overall weight of evidence say? You invoked statistics, so let's do some. What are the numbers? I feel like I'm getting nowhere with this discussion.
    You can use Google can't you ?

    Those links I gave are just some random ones that I found quickly. There are some much better papers out there to be found.

    You will see that they are very dismissive of ETs not being able to travel or communicate.

  4. #724
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by kzb View Post
    You can use Google can't you ?

    Those links I gave are just some random ones that I found quickly. There are some much better papers out there to be found.

    You will see that they are very dismissive of ETs not being able to travel or communicate.
    You are the one who keeps insisting that your view is mainstream and supported. My own research has always shown the opposite.

    I have never, once, said that ETIs could not travel or communicate. I have said, repeatedly and in many ways, that doing so is massively difficult and very limited in scope compared to the overall scales of the Universe, both in space and time.

    To accuse me of saying that, suggests to me that you aren't really getting what I've been talking about all along.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  5. #725
    Join Date
    May 2004
    Posts
    1,945
    Quote Originally Posted by kzb View Post
    But how have they estimated how long each stage should take?
    It is an argument that, if each stage took far longer than the age of the universe to "typically" happen, BUT if you "forced" all of them to happen on a planet anyway (Earth), then each would take a equal fraction of the period where they have been possible, with the remaining "lifespan" of the planet equal to one of the previous stages. The stages would all be equal even if one of them (for example) were astronomically longer than the other five.
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  6. #726
    Join Date
    Jan 2002
    Location
    The Valley of the Sun
    Posts
    9,706
    Maybe technological advancement eventually levels off and the billion year old civilizations are very far ahead of us.

  7. #727
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Noclevername View Post
    You are the one who keeps insisting that your view is mainstream and supported. My own research has always shown the opposite.

    I have never, once, said that ETIs could not travel or communicate. I have said, repeatedly and in many ways, that doing so is massively difficult and very limited in scope compared to the overall scales of the Universe, both in space and time.

    To accuse me of saying that, suggests to me that you aren't really getting what I've been talking about all along.
    Yes I do understand the point you are making and I am trying to answer it. It is a fair point that we do not know for a fact that such travel and communication will ever be possible. All I am saying is the assumption that it will be possible for sufficiently advanced ETs is made by a great many persons publishing in this field. And I tend to go with them on this point. See for example what it says in one of my random links from above. And this is just one example out of many:


    https://arxiv.org/abs/1509.02832

    Explanations falling into the second category are often regarding the difficulties of interstellar travel. Given the findings of this and Lineweaver et al. (2004) study that the average habitable planet is predicted to be billions of years older than the Earth, we would expect any ETC older than us (and therefore likely to be engaging in space exploration) to be on average billions of years more advanced than we currently are, it therefore seems extremely unjustified to place restrictions on their level of technological ability.

  8. #728
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Tom Mazanec View Post
    It is an argument that, if each stage took far longer than the age of the universe to "typically" happen, BUT if you "forced" all of them to happen on a planet anyway (Earth), then each would take a equal fraction of the period where they have been possible, with the remaining "lifespan" of the planet equal to one of the previous stages. The stages would all be equal even if one of them (for example) were astronomically longer than the other five.
    Now, this one, I don't understand !

  9. #729
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by kzb View Post
    Given the findings of this and Lineweaver et al. (2004) study that the average habitable planet is predicted to be billions of years older than the Earth, we would expect any ETC older than us (and therefore likely to be engaging in space exploration) to be on average billions of years more advanced than we currently are, it therefore seems extremely unjustified to place restrictions on their level of technological ability.[/I]
    Yes, I agree. There may very well be advanced technological societies, as I had already acknowledged above. And so what? It has literally nothing to do with what I argued.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  10. #730
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by kzb View Post
    Given the findings of this and Lineweaver et al. (2004) study that the average habitable planet is predicted to be billions of years older than the Earth, we would expect any ETC older than us (and therefore likely to be engaging in space exploration) to be on average billions of years more advanced than we currently are, it therefore seems extremely unjustified to place restrictions on their level of technological ability.[/I]
    Yes, and so what?

    My argument was never that there are not opinions on the subject. But claiming that an opinion based on no facts is valid jut because there's been speculation about it, is just Argument From Authority. It's no more valid than fantasy football.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  11. #731
    Join Date
    Feb 2010
    Posts
    42
    Quote Originally Posted by kzb View Post
    it therefore seems extremely unjustified to place restrictions on their level of technological ability.[/I]
    Really? It is unjustified to assume that faster than light communication and travel will not be possible no matter how long a civilization lasts? If there are no physical laws that we can assume to hold true over time, I don't see how it is possible to constrain any discussion to something that might be close to reality.

  12. #732
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by ExoZZ View Post
    Really? It is unjustified to assume that faster than light communication and travel will not be possible no matter how long a civilization lasts? If there are no physical laws that we can assume to hold true over time, I don't see how it is possible to constrain any discussion to something that might be close to reality.
    This viewpoint has never depended on breaking our known laws of physics.

  13. #733
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Noclevername View Post
    Yes, and so what?

    My argument was never that there are not opinions on the subject. But claiming that an opinion based on no facts is valid jut because there's been speculation about it, is just Argument From Authority. It's no more valid than fantasy football.
    Well OK you have your belief and I have mine. My belief is shared by the majority of published works on the subject. But granted, science is not a democracy.

  14. #734
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by kzb View Post
    My belief is shared by the majority of published works on the subject.
    [citation needed]
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  15. #735
    Join Date
    Mar 2004
    Posts
    18,680
    Quote Originally Posted by kzb View Post
    Well OK you have your belief and I have mine. My belief is shared by the majority of published works on the subject. But granted, science is not a democracy.
    That’s funny, as I thought that a limited civilization lifetime argument was pretty popular. That is, advanced civilization may not last long for many reasons, and a hundred thousand or million years is incredibly long compared to the decades we’ve had fairly advanced technology. They usually bring up issues we have had or are concerned about: massive war, disease, environmental damage, resource limitations, but there are more subtle ones.

    But really, why should anyone care what unsupportable opinions are popular at the moment?

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  16. #736
    Join Date
    May 2004
    Posts
    1,945
    Quote Originally Posted by Chuck View Post
    Maybe technological advancement eventually levels off and the billion year old civilizations are very far ahead of us.
    You mean NOT very far ahead of us?
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  17. #737
    Join Date
    May 2004
    Posts
    1,945
    Quote Originally Posted by kzb View Post
    Now, this one, I don't understand !
    The book admitted that this is counterintuitive, but said that was what the Bayesian math indicates.
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  18. #738
    Join Date
    Jan 2002
    Location
    The Valley of the Sun
    Posts
    9,706
    Quote Originally Posted by Tom Mazanec View Post
    You mean NOT very far ahead of us?
    I thought I typed "aren't". Maybe I should use my computer keyboard instead of lying in bed posting from my phone.

  19. #739
    Join Date
    Aug 2010
    Posts
    2,237
    Quote Originally Posted by kzb View Post
    Yes I do understand the point you are making and I am trying to answer it. It is a fair point that we do not know for a fact that such travel and communication will ever be possible. All I am saying is the assumption that it will be possible for sufficiently advanced ETs is made by a great many persons publishing in this field. And I tend to go with them on this point. See for example what it says in one of my random links from above. And this is just one example out of many:


    https://arxiv.org/abs/1509.02832

    Explanations falling into the second category are often regarding the difficulties of interstellar travel. Given the findings of this and Lineweaver et al. (2004) study that the average habitable planet is predicted to be billions of years older than the Earth, we would expect any ETC older than us (and therefore likely to be engaging in space exploration) to be on average billions of years more advanced than we currently are, it therefore seems extremely unjustified to place restrictions on their level of technological ability.
    This argument assumes that "older" = "more advanced". That as a civilisation gets older and older, it typically gets smarter and smarter...

    Quote Originally Posted by Chuck View Post
    Maybe technological advancement eventually levels off and the billion year old civilizations are very far ahead of us.
    Quote Originally Posted by Chuck View Post
    I thought I typed "aren't". Maybe I should use my computer keyboard instead of lying in bed posting from my phone.
    Now that you've clarified that, I think the point you're making is an important one. Another way I've seen it expressed, is that technological innovation may have a "ceiling", and we're actually fairly near it right now.

    For instance, it may be that in 200 years time our descendants will be doing all sort of things we can't do now, BUT

    * they still won't be able to embark on interstellar colonisation
    * they'll have reached a stage where there is very little room for further innovations

    And for the next billion years, their descendants will either (at best) remain the same technical level, or else will go through cycles of decline and recovery, or else just decline and not recover...

    These may seem like pessimistic prospects, but they'll be able to console themselves with the thought that they're neither alone in the universe, nor in danger of interstellar invasion; because they'll figure out that evolution on other worlds will have similar outcomes, with other civilisations emerging and coming up against the same ceiling.

    In short, it may be that we have plenty of cosmic company, but we're never going to meet them.

  20. #740
    Join Date
    Sep 2004
    Posts
    4,233
    The only recent paper (a revised older one) that I think offers "hard" evidence as to the existence of intelligent/technological life elsewhere would be this one, though it reports negative results.

    https://arxiv.org/abs/1906.07750

    The Breakthrough Listen Search for Intelligent Life: Observations of 1327 Nearby Stars over 1.10-3.45 GHz
    Danny C. Price, J. Emilio Enriquez, Bryan Brzycki, Steve Croft, Daniel Czech, David DeBoer, Julia DeMarines, Griffin Foster, Vishal Gajjar, Nectaria Gizani, Greg Hellbourg, Howard Isaacson, Brian Lacki, Matt Lebofsky, David H. E. MacMahon, Imke de Pater, Andrew P. V. Siemion, Dan Werthimer, James A. Green, Jane F. Kaczmarek, Ronald J. Maddalena, Stacy Mader, Jamie Drew, S. Pete Worden
    (Submitted on 18 Jun 2019 (v1), last revised 9 Jan 2020 (this version, v2))

    Breakthrough Listen (BL) is a ten-year initiative to search for signatures of technologically capable life beyond Earth via radio and optical observations of the local Universe. A core part of the BL program is a comprehensive survey of 1702 nearby stars at radio wavelengths (1-10 GHz). Here, we report on observations with the 64-m CSIRO Parkes radio telescope in New South Wales, Australia, and the 100-m Robert C. Byrd Green Bank radio telescope in West Virginia, USA. Over 2016 January to 2019 March, a sample of 1138 stars was observed at Green Bank using the 1.10-1.90 GHz and 1.80-2.80 GHz receivers, and 189 stars were observed with Parkes over 2.60{3.45 GHz. We searched these data for the presence of engineered signals with Doppler-acceleration drift rates between -4 to 4 Hz/s. Here, we detail our data analysis techniques and provide examples of detected events. After excluding events with characteristics consistent with terrestrial radio interference, we are left with zero candidates. Given the sensitivity of our observations, we can put an upper limit on the power of potential radio transmitters at these frequencies at 2x10^12 W, and 9x10^12 W for GBT and Parkes respectively. These observations constitute the most comprehensive search over 1.10-3.45 GHz for technosignatures to date for Kardashev Type I civilizations. All data products, totalling ~219 TB, are available for download as part of the first BL data release (DR1), as described in a companion paper (Lebofsky et. al., 2019)
    Do good work. —Virgil Ivan "Gus" Grissom

  21. #741
    Join Date
    Sep 2004
    Posts
    4,233
    Speaking of the Breakthrough Listen project, maybe part of the problem in SETI is that we aren't thinking like aliens.

    https://www.space.com/seti-extraterr...-research.html

    To find intelligent alien life, humans may need to start thinking like an extraterrestrial
    By Adam Mann 2 hours ago

    Our hunt for aliens has a potentially fatal flaw — we're the ones searching for them.

    That's a problem because we're a unique species, and alien-seeking scientists are an even stranger and more specialized bunch. As a result, their all-too human assumptions may get in the way of their alien-listening endeavors. To get around this, the Breakthrough Listen project, a $100-million initiative scouring the cosmos for signals of otherworldly beings as part of the Search for Extraterrestrial Intelligence (SETI), is asking anthropologists to help unmask some of these biases.

    "It's kind of a joke at Breakthrough Listen," Claire Webb, an anthropology and history of science student at the Massachusetts Institute of Technology, said here on Jan. 8 at the 235th meeting of the American Astronomical Society (AAS) in Honolulu. "They tell me: 'We're studying aliens, and you're studying us.'"

    Since 2017, Webb has worked with Breakthrough Listen to examine how SETI researchers think about aliens, produce knowledge, and perhaps inadvertently place anthropocentric assumptions into their work.

    She sometimes describes her efforts as "making the familiar strange."

    For instance, your life might seem perfectly ordinary — maybe involving being hunched over at a desk and shuttling electrons around between computers — until examined through an anthropological lens, which points out that this is not exactly a universal state of affairs. At the conference, Webb presented a poster looking at how Breakthrough Listen scientists use artificial intelligence (AI) to sift through large data sets and try to uncover potential technosignatures, or indicators of technology or tool use by alien organisms.

    "Researchers who use AI tend to disavow human handicraft in the machines they build," Webb told Live Science. "They attribute a lot of agency to those machines. I find that somewhat problematic and at the worst untrue."

    Any AI is trained by human beings, who present it with the types of signals they think an intelligent alien might produce. In doing so, they predispose their algorithms to certain biases. It can be incredibly difficult to recognize such thinking and overcome its limitations, Webb said.
    Last edited by Roger E. Moore; 2020-Jan-25 at 05:29 PM.
    Do good work. —Virgil Ivan "Gus" Grissom

  22. #742
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Van Rijn View Post
    That’s funny, as I thought that a limited civilization lifetime argument was pretty popular. That is, advanced civilization may not last long for many reasons, and a hundred thousand or million years is incredibly long compared to the decades we’ve had fairly advanced technology. They usually bring up issues we have had or are concerned about: massive war, disease, environmental damage, resource limitations, but there are more subtle ones.

    But really, why should anyone care what unsupportable opinions are popular at the moment?
    Yes of course the limited civilisation lifetime explanation is very well known. It was probably THE explanation back in the 1960's and 1970's when it was assumed there would be a nuclear war in the near future.

    But that is not what I was discussing. The concept I was discussing was there being loads of ETs out there, but we do not detect any sign of their presence. That is a different idea, because it is saying civilisations can last for millions or billions of years without making any detectable sign of their presence. it's a different point.

  23. #743
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Colin Robinson View Post
    This argument assumes that "older" = "more advanced". That as a civilisation gets older and older, it typically gets smarter and smarter...





    Now that you've clarified that, I think the point you're making is an important one. Another way I've seen it expressed, is that technological innovation may have a "ceiling", and we're actually fairly near it right now.

    For instance, it may be that in 200 years time our descendants will be doing all sort of things we can't do now, BUT

    * they still won't be able to embark on interstellar colonisation
    * they'll have reached a stage where there is very little room for further innovations

    And for the next billion years, their descendants will either (at best) remain the same technical level, or else will go through cycles of decline and recovery, or else just decline and not recover...

    These may seem like pessimistic prospects, but they'll be able to console themselves with the thought that they're neither alone in the universe, nor in danger of interstellar invasion; because they'll figure out that evolution on other worlds will have similar outcomes, with other civilisations emerging and coming up against the same ceiling.

    In short, it may be that we have plenty of cosmic company, but we're never going to meet them.
    Yes this is a possibility, but that is all. I would argue you can make this point, but the available evidence actually supports the opposite view.

    How many times in history have people written about the end of knowledge, physics is complete it's now just tidying up a bit. Only the other year I saw an article on chemistry being virtually complete.

    Every single time these have turned out to be badly mistaken. So yes it is a possibility, but history teaches the opposite will be true.

  24. #744
    Join Date
    May 2004
    Posts
    1,945
    kzb:
    I think we will run out of things to discover eventually. But I don't think we are anywhere near that.
    Another possibility is that humanity is not intelligent enough to discover the real truth, that it is something we could never understand or develop.
    SHARKS (crossed out) MONGEESE (sic) WITH FRICKIN' LASER BEAMS ATTACHED TO THEIR HEADS

  25. #745
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by Tom Mazanec View Post
    kzb:
    I think we will run out of things to discover eventually. But I don't think we are anywhere near that.
    Another possibility is that humanity is not intelligent enough to discover the real truth, that it is something we could never understand or develop.
    What do you mean by, "the real truth"?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  26. #746
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Noclevername View Post
    What do you mean by, "the real truth"?
    We won't know until we find it, that is the whole point. It is called the Transcendental category of explanations.

    The idea that we could be a computer simulation being run by an advanced race has come to the fore in recent years.

    A few decades ago we could have had no concept of this. I am not saying this is the answer, just that until quite recently no-one could have even thought it up. What next?

  27. #747
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Tom Mazanec View Post
    kzb:
    I think we will run out of things to discover eventually. But I don't think we are anywhere near that.
    Another possibility is that humanity is not intelligent enough to discover the real truth, that it is something we could never understand or develop.
    Some people have been thinking up ways we could discover if we are a computer simulation. I think they've been debunked but perhaps sooner or later this could be established. Then what ?

  28. #748
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by kzb View Post
    We won't know until we find it, that is the whole point. It is called the Transcendental category of explanations.
    Explanation for what?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  29. #749
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,462
    Quote Originally Posted by Noclevername View Post
    Explanation for what?
    If you mean, for the Fermi "paradox", how would it explain that?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  30. #750
    Join Date
    Apr 2005
    Posts
    2,606
    Quote Originally Posted by Noclevername View Post
    Explanation for what?
    The Fermi paradox.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •