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Fermi paradox, your own belief?
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#12
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Fermi paradox, your own belief?
In sci.astro.amateur,rec.arts.sf.science, Michael Ash
wrote: On Fri, 18 Jun 2004, gswork wrote: ON the off chance you don't know, Fermi's paradox is basically - if even conservative estimates suggest that adanced life in the galaxy is abundant then even more conservative estimates show that the entire galaxy should be explored already, so why aren't the aliens here? I don't like the namee "paradox" for this, I think it's too strong a word for the evidence or lack of. I'd rather think of it as Fermi's Question [ISTR Carl Sagan polularized it by asking it in his "Cosmos" TV series], which is simply "Where are they?" The implication that galaxies should be rainbows/melting pots of different sentient species which developed in different solar systems and developed interstellar travel is based on a BOTE calculation using a lot of "assumed" [and you know what that word means] numbers for the conditions believed needed for intelligent life to evolve. various reasons are given as to why they're not : advaned life is rarer than we thought, space travel is more difficult than we think, they are here(!), they've put us in quarantine until we grow up, civilisation destroy themselves at some crucial point etc etc. Or we may simply be the first. Somebody had to be first, why not us? The "paradox" holds about as much water as that theory that we must be near the end of the world because exponential population growth means there's a 95% chance that any given person will be born within a lifetime of the end, or however it goes. warning, topic drift Now, here's an interesting thought, I think I read it at foresight.org or some other transhumanist writing. Mankind (or any species) cannot even theoretically continue to grow indefinitely at its current exponential rate. The exponential will eventually overtake the cubic volume expansion at the speed of light, so even assuming there's enough food and other resources, exponential growth will eventually cause population density to increase even with mankind expanding at lightspeed in all directions. But now that I think about this, it fails to take into account the slowing of time as one approaches lightspeed. (In another blatant abuse of the word [I'm sure someone, perhaps even Einstein, called it this, and the name stuck], this is often called the "Twin Paradox" even though it's not a paradox at all - I always wondered what was paradoxical about it). Time slows (relative to those stuck on planets and in freefall) and thus lowers the rate of reproduction, so perhaps near-lightspeed travel is the only answer for mankind maintaining "apparent-exponential" growth. ----- http://mindspring.com/~benbradley |
#13
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Fermi paradox, your own belief?
In sci.astro.amateur,rec.arts.sf.science, Michael Ash
wrote: On Fri, 18 Jun 2004, gswork wrote: ON the off chance you don't know, Fermi's paradox is basically - if even conservative estimates suggest that adanced life in the galaxy is abundant then even more conservative estimates show that the entire galaxy should be explored already, so why aren't the aliens here? I don't like the namee "paradox" for this, I think it's too strong a word for the evidence or lack of. I'd rather think of it as Fermi's Question [ISTR Carl Sagan polularized it by asking it in his "Cosmos" TV series], which is simply "Where are they?" The implication that galaxies should be rainbows/melting pots of different sentient species which developed in different solar systems and developed interstellar travel is based on a BOTE calculation using a lot of "assumed" [and you know what that word means] numbers for the conditions believed needed for intelligent life to evolve. various reasons are given as to why they're not : advaned life is rarer than we thought, space travel is more difficult than we think, they are here(!), they've put us in quarantine until we grow up, civilisation destroy themselves at some crucial point etc etc. Or we may simply be the first. Somebody had to be first, why not us? The "paradox" holds about as much water as that theory that we must be near the end of the world because exponential population growth means there's a 95% chance that any given person will be born within a lifetime of the end, or however it goes. warning, topic drift Now, here's an interesting thought, I think I read it at foresight.org or some other transhumanist writing. Mankind (or any species) cannot even theoretically continue to grow indefinitely at its current exponential rate. The exponential will eventually overtake the cubic volume expansion at the speed of light, so even assuming there's enough food and other resources, exponential growth will eventually cause population density to increase even with mankind expanding at lightspeed in all directions. But now that I think about this, it fails to take into account the slowing of time as one approaches lightspeed. (In another blatant abuse of the word [I'm sure someone, perhaps even Einstein, called it this, and the name stuck], this is often called the "Twin Paradox" even though it's not a paradox at all - I always wondered what was paradoxical about it). Time slows (relative to those stuck on planets and in freefall) and thus lowers the rate of reproduction, so perhaps near-lightspeed travel is the only answer for mankind maintaining "apparent-exponential" growth. ----- http://mindspring.com/~benbradley |
#14
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Fermi paradox, your own belief?
Matthew Ota wrote:
:This is why I do not run the SETI at Home screen saver. I consider it a :waste of time. Go with PrimeNet! : :Matthew Ota -- They say there's air in your lungs that's been there for years. George W. Harris For actual email address, replace each 'u' with an 'i'. |
#15
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Fermi paradox, your own belief?
Matthew Ota wrote:
:This is why I do not run the SETI at Home screen saver. I consider it a :waste of time. Go with PrimeNet! : :Matthew Ota -- They say there's air in your lungs that's been there for years. George W. Harris For actual email address, replace each 'u' with an 'i'. |
#16
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Fermi paradox, your own belief?
I've read a number of books and papers on this topic, and I am struck by the large number of quite valid reasons to expect the current state of affairs, even if there are quite a few intelligent races in this galaxy besides our own. My personal favorite explanation is that expansion of races to planets other than the one they originate from is much harder than expected, thus limiting the likelihood of gradual colonization and easier communication. When left with only the possibility of probes reaching other populations, myriad problems remain for this being successful for any given such population. In any case, keep in mind that all that is needed on one simple event (among numerous possibilities) for this "paradox" to evaporate into thin air permanently. Alan "gswork" wrote in message om... ON the off chance you don't know, Fermi's paradox is basically - if even conservative estimates suggest that adanced life in the galaxy is abundant then even more conservative estimates show that the entire galaxy should be explored already, so why aren't the aliens here? various reasons are given as to why they're not : advaned life is rarer than we thought, space travel is more difficult than we think, they are here(!), they've put us in quarantine until we grow up, civilisation destroy themselves at some crucial point etc etc. This is old hat for many, but it may interest or stimulate you. I'm really just looking for opinions, your opinions on why we don't encounter aliens regularly. The one i tend to believe is that whilst life may not be so overwhelmingly rare, advanced technological space faring life is - very very rare indeed. So rare it may even be that we are alone in this galaxy, or maybe sharing with a handful of others dotted around the milky way, with one each in the magallenic clouds! I think this because, based on what i've read, Earth has been around for nearly 5 billion years, microscopic life for perhaps 3 billion, and more complex life for only 700 million or so. Not only that but left to it's own devices the Earth would have only another few hundred million years before the Sun's ever increasing heat output starts to tip the delicate balance of the eco system and potentially make it too hostile to complex life, driving life back into the seas, back into more primitive forms. A couple of billion years hence, maybe more, the earth tips over into runaway greenhouse and becomes a milder, but equally deadly version of Venus, utterly devoid of life. Later still the sun exits the main sequence, becomes a red giant, and that's pretty much it for the inner 3 planets. So Earth can support complex life for something like 1.5 billion years start to finish. It took half that to to get to Humans, and were not 100% sure that we are really a space faring race (in interstellar terms) or will last long enough to become one. If the dinosaur killer event didn't happen then there'd be no reason for humans to exist. Indeed it would only take a series of subtle variations and humans would not have evolved at all. The evolution of technological advanced intelligent animals seems really very precarious. Life itself may be rarer than we think, and space faring life may be so exceptional that it's more likely we *won't* encounter aliens. An interesting book on this is Isaac Asimov's 'Extraterrestrial Civilisations'. It's a 1979 book (IIRC) so the science is occasionally missing a later discovery or theory, but mostly it makes sense today and is well written and interesting. (perhaps you have book recommendations in this area too?) |
#17
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Fermi paradox, your own belief?
I've read a number of books and papers on this topic, and I am struck by the large number of quite valid reasons to expect the current state of affairs, even if there are quite a few intelligent races in this galaxy besides our own. My personal favorite explanation is that expansion of races to planets other than the one they originate from is much harder than expected, thus limiting the likelihood of gradual colonization and easier communication. When left with only the possibility of probes reaching other populations, myriad problems remain for this being successful for any given such population. In any case, keep in mind that all that is needed on one simple event (among numerous possibilities) for this "paradox" to evaporate into thin air permanently. Alan "gswork" wrote in message om... ON the off chance you don't know, Fermi's paradox is basically - if even conservative estimates suggest that adanced life in the galaxy is abundant then even more conservative estimates show that the entire galaxy should be explored already, so why aren't the aliens here? various reasons are given as to why they're not : advaned life is rarer than we thought, space travel is more difficult than we think, they are here(!), they've put us in quarantine until we grow up, civilisation destroy themselves at some crucial point etc etc. This is old hat for many, but it may interest or stimulate you. I'm really just looking for opinions, your opinions on why we don't encounter aliens regularly. The one i tend to believe is that whilst life may not be so overwhelmingly rare, advanced technological space faring life is - very very rare indeed. So rare it may even be that we are alone in this galaxy, or maybe sharing with a handful of others dotted around the milky way, with one each in the magallenic clouds! I think this because, based on what i've read, Earth has been around for nearly 5 billion years, microscopic life for perhaps 3 billion, and more complex life for only 700 million or so. Not only that but left to it's own devices the Earth would have only another few hundred million years before the Sun's ever increasing heat output starts to tip the delicate balance of the eco system and potentially make it too hostile to complex life, driving life back into the seas, back into more primitive forms. A couple of billion years hence, maybe more, the earth tips over into runaway greenhouse and becomes a milder, but equally deadly version of Venus, utterly devoid of life. Later still the sun exits the main sequence, becomes a red giant, and that's pretty much it for the inner 3 planets. So Earth can support complex life for something like 1.5 billion years start to finish. It took half that to to get to Humans, and were not 100% sure that we are really a space faring race (in interstellar terms) or will last long enough to become one. If the dinosaur killer event didn't happen then there'd be no reason for humans to exist. Indeed it would only take a series of subtle variations and humans would not have evolved at all. The evolution of technological advanced intelligent animals seems really very precarious. Life itself may be rarer than we think, and space faring life may be so exceptional that it's more likely we *won't* encounter aliens. An interesting book on this is Isaac Asimov's 'Extraterrestrial Civilisations'. It's a 1979 book (IIRC) so the science is occasionally missing a later discovery or theory, but mostly it makes sense today and is well written and interesting. (perhaps you have book recommendations in this area too?) |
#18
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Fermi paradox, your own belief?
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#19
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Fermi paradox, your own belief?
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#20
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Fermi paradox, your own belief?
"gswork" wrote in message om... ON the off chance you don't know, Fermi's paradox is basically - if even conservative estimates suggest that adanced life in the galaxy is abundant then even more conservative estimates show that the entire galaxy should be explored already, so why aren't the aliens here? My belief is that Someone much more powerful than even the universe itself controls it. Therefore, barriers, such as the enormous distance between stars, were already put in place before the universe was created. There are certain thresholds that no one will ever cross. Jon |
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