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The Fermi Paradox and SETI Success
In article ,
William Hamblen wrote: On Wed, 13 Aug 2008 19:01:27 -0700, Timberwoof wrote: In article , John Harshman wrote: Who says water is an indicator of life? It's only claimed to be necessary for life. Methane, as far as I know, is never mentioned. Oxygen is the indicator of life, and if you want to suggest an inorganic process that can make a lot of free oxygen in an atmosphere, feel free. Only oxygen? Yeah... it's common and it does some handy chemical reactions. But similar arguments can be made for water. Oxygen is reactive enough that oxygen in the atmosphere would be depleted unless restored from some source. The only likely source is photosynthesis. Where you have atmospheric oxygen you have living plants. Yes, that makes sense. I had it in my head that other chemical bases for live were being discussed, and perhaps some other element or compound could fulfill a similar role. But I agree: If oxygen is present in an atmosphere, that would be a really really probable sign of life. :-) -- Timberwoof me at timberwoof dot com http://www.timberwoof.com People who can't spell get kicked out of Hogwarts. |
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The Fermi Paradox and SETI Success
Timberwoof wrote:
In article , John Harshman wrote: Who says water is an indicator of life? It's only claimed to be necessary for life. Methane, as far as I know, is never mentioned. Oxygen is the indicator of life, and if you want to suggest an inorganic process that can make a lot of free oxygen in an atmosphere, feel free. Only oxygen? Yeah... it's common and it does some handy chemical reactions. But similar arguments can be made for water. No they can't. Unlike water, free oxygen is not common anywhere that I know of except on earth, where it's made by life. Water is all over, a product of inorganic chemistry. |
#13
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The Fermi Paradox and SETI Success
On Aug 13, 8:38 pm, John Harshman
wrote: K_h wrote: Fermi's paradox suggests that there are little or no other intelligent civilizations within the Milky Way galaxy. On the other hand, intelligent life should exist on a substantial fraction of planets with life because natural selection broadly increases intelligence with time. Does it? News to me. What evidence do you have that this is the case? There has been an increase in the intelligence of a broad range of species on earth with time. |
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The Fermi Paradox and SETI Success
On Wed, 13 Aug 2008 21:41:58 -0700 (PDT), Friar Broccoli
wrote: There has been an increase in the intelligence of a broad range of species on earth with time. That is not obvious. We have almost no idea at all about the intelligence of animals over most of the period they have existed. Except for humans, and possibly a handful of other species, it isn't clear that a "broad range of species" is any more intelligent now than several hundred million years ago. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
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The Fermi Paradox and SETI Success
Friar Broccoli wrote:
On Aug 13, 8:38 pm, John Harshman wrote: K_h wrote: Fermi's paradox suggests that there are little or no other intelligent civilizations within the Milky Way galaxy. On the other hand, intelligent life should exist on a substantial fraction of planets with life because natural selection broadly increases intelligence with time. Does it? News to me. What evidence do you have that this is the case? There has been an increase in the intelligence of a broad range of species on earth with time. Has there? What broad range, exactly? And if natural selection broadly increased intelligence with time, we would expect all species to be undergoing this push, wouldn't we? Yet we see that brains exist only in a small subset of species within one restricted clade (Metazoa), and that, depending on how you define the word, complex brains exist only in a small subset of those (which I will choose to interpret here as Cephalopoda and Gnathostomata), and that particular complex ones exist only in a small subset of those (Aves and Mammalia), and that only one species has human-level intelligence, and from observing usenet, that only rarely. It's hard to consider this a general trend. Similar results could be achieved by random diffusion starting at a barrier, with a great deal of variance in the intelligence of the extreme tail. |
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The Fermi Paradox and SETI Success
Eric wrote:
K_h wrote: Fermi's paradox suggests that there are little or no other intelligent civilizations within the Milky Way galaxy. Not to me it doesnt. To me, it simply says either they havent found this area interesting to explore, or (more likely) its too far to travel. Even if ET can travel at faster than light, it will take a very very long time to explore even a small part of the galaxy. Galaxy is 100,000 light years in diameter. Age of universe is 13,730,000,000 years. Aliens who could travel at the speed of light could zip back and forth across the galaxy some 68,650 times in that time. So: the galaxy is pretty small, cosmically speaking - and so the original interpretation of the Fermi paradox is probably not far off: if there are intelligent aliens in our galaxy, odds are they are would be everywhere - so probably there are no aliens in our galaxy - and SETI is mostly barking up the wrong tree. -- __________ |im |yler http://timtyler.org/ Remove lock to reply. |
#17
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The Fermi Paradox and SETI Success
Sod the chemistry! Every assumption we make is only that. We know
almost nothing about our own planet. Particularly below the surface of the seas which cover much of our own world. We cannot imagine any dominantly intelligent species not having our avarice, aggression and chronic immorality. It is completely beyond our way of thinking except in sci-fantasy terms. Our intelligence is based on learning to take something from somebody else, by force, rather than obtaining it for ourselves. Hierarchy is a corruption built into our genes. A coat of paint to disguise theft by the strongest from the weakest. Strongest always wins. We even equate this with survival of species. Survival of the fittest. Fittest for what exactly? Resource depletion and genocide? We assume that no other "alien" species is as curious or driven to explore because they haven't yet taken advanatge of the White House Lawn's excellent landing facilities. Did any other species need to escape endlessly from the destruction of its habitat due to overcrowding, corruption at the top of the local mafia and yet more resource depletion? Africa has hardly moved on in millions of years. Is Afria on another planet? Are the present inhabitants another race? Or have they merely borrowed our more destructive toys to continue their inter-tribal wars of stick waving? Is modern America any more than a bunch of stick wavers ihabiting the last remaining vestiges of their particular bit of the global jungle? They took it from the last lot and it seems that others will soon outbreed them. To repeat the land theft trick in a more subtle way. Survival of the fittest? Fit for what? Slum dwelling, crime and drugs abuse? Who knows how many intelligent races out there see the scourge of the human race as the most dangerous threat to *their* survival? They may be operating a no-go zone around us out to dozens of light years. Just to keep us safely locked in. If we ever go hyperdrive we may suddenly cease to exist. Survival of the fittest may have not count for us when we finally have the ability to spread the human infection. The bared teeth are only ever a moment away. Pass me my stick. No, I like yours better. I will take yours! |
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The Fermi Paradox and SETI Success
On Aug 13, 8:12 pm, "K_h" wrote:
On the other hand, intelligent life should exist on a substantial fraction of planets with life because natural selection broadly increases intelligence with time. I quite disagree witht his part. Indeed, I think "intelligence", particularly in the form of the "technological intelligence" required for SETI, is an abject evolutionary failure. In our short tenure as a species, and even in our microscopic-timed tenure as a technological species, we've managed to produce the largest mass extinction since the Cretaceous, and have put not only our own survival as a species at risk, but the very existence of nearly the entire biosphere within which we live. It seems pretty logical to me that there should be NO other technological intelligent species in the universe at the current time, because they all kill themselves off (probably taking much of their planet's life with them) before anyone else even knows they are there. "Intelligence" is an evolutionary path to quick suicide. A dead end. Literally. ================================================ Lenny Flank "There are no loose threads in the web of life" Editor, Red and Black Publishers http://www.RedAndBlackPublishers.com |
#19
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The Fermi Paradox and SETI Success
On Aug 13, 9:58*pm, Timberwoof
wrote: In article , *Chris L Peterson wrote: On Wed, 13 Aug 2008 17:12:57 -0700, "K_h" wrote: This contradiction can be resolved if the origin of life is far harder than commonly believed... My thinking is that life is easy, and probably common. It's the part about it becoming (technologically) intelligent that's more likely to be difficult and rare. I see nothing to suggest that there are many species on Earth poised to become technological given a few million years of evolution. Most species have been around and stable for at least that long. Given the vast numbers of species on Earth, living and extinct, and the presence of only one technological one- which happens to be of very recent origin and likely on the edge of extinction itself- that seems like the weak link in the Drake chain, and therefore a reasonable answer to the Fermi Paradox. I suspect that just as when one system of biochemistry establishes the pattern of life, things that use it will eat anything else that shows up, it is likely that when one highly intelligent species shows up, it will limit the opportunities for anything else to evolve into sentience. I am not a scientist, but I get the notion that that applies to niches in general: organisms will usually be more successful if they find a new niche, or an underutilized one, than if they try to horn in on a niche that already has well-adapted occupants. The final events that drove human evolution to intelligence were all climatic changes. For example, when forests of Africa became savannah, the apes that lived there had to adapt, and they ended up going down the road to high intelligence. It's interesting to note that this also happened only in once place, and then humans spread out to everywhere. There are plenty of species running around on the Earth now that are at about the level of intelligence of our ancestors, oh, twenty million years ago. They're not likely to develop to sentience any time soon, and certainly not while we're around unless we help them. (David Brin has written science fiction novels around that concept ... in his universe we're a rare event, independently developed sentience. That causes a lot of political trouble for us in the interstellar culture.) But if we were to off ourselves suddenly, the Earth would heal and something might have a chance to develop sentience. -- Timberwoof me at timberwoof dot comhttp://www.timberwoof.com People who can't spell get kicked out of Hogwarts. Eric Root |
#20
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The Fermi Paradox and SETI Success
On Aug 14, 7:41*am, "'Rev Dr' Lenny Flank" wrote:
On Aug 13, 8:12 pm, "K_h" wrote: *On the other hand, intelligent life should exist on a substantial fraction of planets with life because natural selection broadly increases intelligence with time. I quite disagree witht his part. *Indeed, I think "intelligence", particularly in the form of the "technological intelligence" required for SETI, is an abject evolutionary failure. *In our short tenure as a species, and even in our microscopic-timed tenure as a technological species, we've managed to produce the largest mass extinction since the Cretaceous, and have put not only our own survival as a species at risk, but the very existence of nearly the entire biosphere within which we live. It seems pretty logical to me that there should be NO other technological intelligent species in the universe at the current time, because they all kill themselves off (probably taking much of their planet's life with them) before anyone else even knows they are there. "Intelligence" is an evolutionary path to quick suicide. *A dead end. Literally. ================================================ Lenny Flank "There are no loose threads in the web of life" Editor, Red and Black Publishershttp://www.RedAndBlackPublishers.com Hmm, you are probably right. Eric Root |
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