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  • #76
    Originally posted by Starchild


    My current favourite is that the event(s) that lead to oxygen respiring, eurkaroytic life are rare. While life may be common, we're going to spend a lot of time talking to slime and algae. But I'm a biochemist, of course I'd prefer the biological explanation.

    Regardless, we seem to be the most advanced civilisation locally.
    That's odd. I would have thought for carbon based lifeforms in an aqueous environment the poisoning of the environment with large amounts of oxygen would be almost inevitable unless the whole system is purely chemotrophic with no external energy source in which case it would be likely to end with an whimper anyway.

    Do you agree that once oxygen waste reaches a certain level that oxygen respiration will become very likely?

    What step leading to oxygen respiration do you see as unlikely?

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    • #77
      Originally posted by DanS
      I don't know. The private sector isn't something that you command to do what you wish it to do. But certainly, it would be on a healthier footing. And we would not have wasted so many careers.
      The private sector is good at wasting careers too. I'm not seeing a lot of return on societies investments in marketing and sales careers for example.
      Last edited by Geronimo; January 9, 2008, 16:39.

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      • #78
        Originally posted by Starchild

        Regardless, we seem to be the most advanced civilisation locally.
        Nope, we are the third most advanced race on Earth. The first being mice and the second dolphins.
        Modern man calls walking more quickly in the same direction down the same road “change.”
        The world, in the last three hundred years, has not changed except in that sense.
        The simple suggestion of a true change scandalizes and terrifies modern man. -Nicolás Gómez Dávila

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        • #79
          Originally posted by Arrian


          I'm going with "vast gaps in space/time" personally. Perhaps there is an advanced civilization in the galaxy, but they're all the way 'round the other side. Perhaps there isn't now, but there was one 2 million years ago. Perhaps there is one now, but we haven't detected their signals yet because said signals won't get here for another 2 million years... and so on and so forth.

          -Arrian
          That one sounds very plausible to me. Our few thousands of years of development would be unlikely to overlap enough with a species close enough that any real contact would be made.
          You don't get to 300 losses without being a pretty exceptional goaltender.-- Ben Kenobi speaking of Roberto Luongo

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          • #80
            Originally posted by Geronimo


            That's odd. I would have thought for carbon based lifeforms in an aqueous environment the poisoning of the environment with large amounts of oxygen would be almost inevitable unless the whole system is purely chemotrophic with no external energy source in which case it would be likely to end with an whimper anyway.

            Do you agree that once oxygen waste reaches a certain level that oxygen respiration will become very likely?

            What step leading to oxygen respiration do you see as unlikely?
            The book which expounded on this idea is several hundred miles away, so lets see if I can remember the arguments off the top of my head:

            There's no problem with oxygen respiring life itself. There's evidence that Luca had defensive mechanisms against oxidative stress long before oxygen became a major component of the environment, purely to deal with reactive species created by UV radiation splitting water. Oxygen metabolism itself is highly useful if you can get the biochemical hang of it since you get the most bang for your buck out of your fuel.

            Its oxygen breathing eukaroytic life that's a problem. That requires the endosymbiotic event joining the ancestral mitocondria with an ancestral eukaryotic cell. That allowed a division of labour between the energy producing centres, with their own minimal genomes able to respond rapidly to finetune the machinery, and the nucleus, which was big enough and shielded from energy production byproducts, to gain the informational complexity required for higher orders of life like being multicellular.

            Now off the top of my head, I can't recall why the endosymbiotic event itself is so unlikely.
            Exult in your existence, because that very process has blundered unwittingly on its own negation. Only a small, local negation, to be sure: only one species, and only a minority of that species; but there lies hope. [...] Stand tall, Bipedal Ape. The shark may outswim you, the cheetah outrun you, the swift outfly you, the capuchin outclimb you, the elephant outpower you, the redwood outlast you. But you have the biggest gifts of all: the gift of understanding the ruthlessly cruel process that gave us all existence [and the] gift of revulsion against its implications.
            -Richard Dawkins

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            • #81
              Originally posted by Flubber


              That one sounds very plausible to me. Our few thousands of years of development would be unlikely to overlap enough with a species close enough that any real contact would be made.
              Right and civs don't even have to be limited to a few thousand years for this to work. As Blake mentioned there are plenty of ways for a previously visible civ to drop off of our radar so to speak and become undetectable.

              Still this does leave unsolved the question as to why a willfully expansive civ hasn't developed (if one had it would have had plenty of time to expand into our solar system). It's not hard to imagine an intelligent species with an overwhelming instinct to expand. Furthermore if they are to be checked by an anti-space pollution civ of some sort the anti-pollution civ will be at a disadvantage unless it enjoys substantial technological superiority over all other almost since the dawn of it's existence.
              Last edited by Geronimo; January 9, 2008, 17:12.

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              • #82
                Originally posted by Starchild
                Now off the top of my head, I can't recall why the endosymbiotic event itself is so unlikely.
                Unless we regard some sort of phagocytosis as unlikely it's hard for me to understand how endosymbiotic events would be unlikely.


                I wonder if the late onset of the cambrian 'explosion' might indicate rather that the jump to multicellular life is the real bottleneck. Both oxygen respiration and eukaryotic life appear to have far more ancient origins.

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                • #83
                  Originally posted by Arrian
                  Radical Islam taking over as top dog in science and space exploration is truely hilarious.

                  -Arrian
                  It's like no one here played SMAC.

                  Comment


                  • #84
                    Originally posted by OneFootInTheGrave
                    and "rare earth" position is just one of the optional answers. My bet is on "do not want to be detected"/"are too advanced for communication to be meaningfull" position
                    The Fermi paradox still applies to the lack of observed radio signals.

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                    • #85
                      Originally posted by Arrian
                      I'm going with "vast gaps in space/time" personally. Perhaps there is an advanced civilization in the galaxy, but they're all the way 'round the other side. Perhaps there isn't now, but there was one 2 million years ago. Perhaps there is one now, but we haven't detected their signals yet because said signals won't get here for another 2 million years... and so on and so forth.

                      -Arrian
                      You don't get the timescales involved. Any civilization could colonize the galaxy in ~3 million years - almost no time. So, if there was other life in our galaxy, it should have done so long, long ago (our galaxy is billions of years old).

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                      • #86
                        That's silly. That's like saying that if you invented a time machine you would already know.
                        Monkey!!!

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                        • #87
                          Originally posted by Geronimo
                          The private sector is good at wasting careers too. I'm not seeing a lot of return on societies investments in marketing and sales careers for example.
                          We give those jobs to people who don't have the skill to do anything productive anyway.

                          Comment


                          • #88
                            Originally posted by Japher
                            That's silly. That's like saying that if you invented a time machine you would already know.
                            That's actually a fantastic argument against the possibility of time travel.

                            Comment


                            • #89
                              Originally posted by Kuciwalker


                              The Fermi paradox still applies to the lack of observed radio signals.
                              not really. onefootinthegrave had said

                              My bet is on "do not want to be detected"/"are too advanced for communication to be meaningfull" position
                              If practically all civs take a short time to progress from discovery of use of radio to digitally compressing almost all of their signals we wouldn't be able to distinguish their radio signals from the noise as they would all have spent far too brief a period of their existence transmitting recognizably artificial radio signals.

                              So in the situation onefoot described the Fermi paradox would no longer apply to the lack of observed radio signals.

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                              • #90
                                Unless all highly-advanced civilizations "go dark", we should be able to pick up signals from [sufficiently advanced] civilizations even in other galaxies.

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