Fermi paradox

Discussion in 'Astronomy, Exobiology, & Cosmology' started by madanthonywayne, Jun 5, 2007.

  1. madanthonywayne Morning in America Registered Senior Member

    Most of you have probably heard of this paradox. There are 250 billion stars in the Milky Way and 70 sextillion in the visible universe. So even if intelligent life occurs on only a minuscule percentage of planets, there should still be a crapload of civilizations in the Milky Way galaxy alone! But where the hell are they? Despite the best efforts of SETI, we have zip to show for it.

    In another thread, we were discussing the question of why it took so long for humans to develope advanced technology.

    After reading thru the thread, I began to wonder. Just how likely is an advanced technological society to develope among intellegent species?

    Was the confluence of events that lead to our quantum leap forward inevitable? Or might we have remained a horse and buggy species indefinitely but for a few lucky breaks?

    Perhaps this is the answer to Enrico Fermi's paradox. Maybe the galaxy is teeming with intellegent alien species tooling around their planets on horses and buggies. Only a very few making the jump forward to high tech. And many of them, no doubt, destroying themselves.

    What do you think?
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  3. Roman Banned Banned

    Maybe intelligent life isn't that dense. Err, that is, the universe is a very large place, and us braniacs could all be spaced very far apart. Or maybe they're on a different frequency?
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  5. redarmy11 Registered Senior Member

    "Ah, Zartek, you're back! I assume you have the latest report on Small Blue Dot #3282292022920028?

    Yes, Captain - and I have both good and bad news for you. The good news is: the inhabitants have largely stopped hitting each other with spiked clubs. The bad news is: they've invented gunpowder. Advise maintain cloaking for at least the next 50,000 years."
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  7. nietzschefan Thread Killer Valued Senior Member

    Lots of possibilities.

    We could be a miniscule footnote of the zrgoppzzzzzzzt(loosely translated) protectorate.

    We were claimed some 500 million years ago and no one has since disputed the claim.

    The zrgoppzzzzzzzt have not yet found the time to capitalize on their prospects in this Galaxy.
  8. Balerion Banned Banned

    Well, considering the size of the Universe, it is no surprise that we can't find intelligent species beyond our planet. We are just beginning to find planets orbiting other stars, let alone what might inhabit them. If there are intelligent species on other planets, it would be hard to find them.

    The closest extra-solar planet that we've found--a one-way trip to it would take 50,000 years--was found by observing the wobbling of its parent star...how would we be able to tell what, if anything, was on the planet?

    That's a good question. If there have been intelligent species on other planets, you would have to assume that some of them had been wiped out by asteroids or some other catastrophic event.

    Well, what exactly are you asking? There haven't been any advances in humans physically from the time we were riding horses. So if the question is more to the idea of "how lucky were we to make the discoveries that lead to the technologies we have today," then I'd have to say we would have found them eventually.

    Since we evolved into Homo Sapiens, our brains have been capable of inventing the technologies we do today. If someone dropped a submarine in our back yard in 900 B.C., and gave us the materials to make another one, we'd eventually be able to reverse-engineer it, and build another one.
  9. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member


    I don't think we took a long time to develop advanced technologies---I think we are average

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    We could even be way ahead of the curve, for all anyone knows.

    Consider this---early on in the evolutionary timescale, we started eating meat. We're pretty sure of this because we have a digestive tract that is half-way between carnivore and herbivore, and our closest relatives, chimps, also eat meat. There is a strong correlation between when we started eating meat, and our brain size---the thinking goes, you have to be more intelligent to hunt than to graze (i.e., dogs vs cows).

    One could imagine, perhaps, a species of intelligent beings that aren't carnivores. Perhaps this is atypical, but who's to say? If this is the case, then the evolution of their culture would have happened in an elongated time period. So are carnivores typical in evolution? Is eating meat a natural thing for creatures to do?

    So either way, it only took us 6000 years to go from bronze to nuclear weapons. The progress in the past century has been even more staggering---look at the average age of death in the developed world, and how dramatically it's increased.

    Plus, it MAY be that there really isn't any hope for getting around the speed of light barrier. We're trapped on this planet, in this solar system. Things like high energy cosmic rays may present an insurmountable barrier to prolonged periods in space, and it may be that we become trapped on Earth and die a prolonged death---by an asteroid, or by cancer when the core stops turning, or when the sun eventually dies.
  10. madanthonywayne Morning in America Registered Senior Member

    That makes it sound like a gradual progression. How about this, it took sixty-six years from the first powered flight to to land a man on the moon!

    The thing is, we were at a horse and buggy level for a long time and then progressed in the blink of an eye from a twelve second barely controlled flight to a trip to the moon and back.

    Which again brings up the question. Was the confluence of cultural and technological events that led to our rapid advancement inevitable, or just lucky? If the "white man" had never come to America, would the indians still be living in the stone age?

    And the same question applies to our missing alien friends.
  11. Balerion Banned Banned

    I'm not so sure there's a way to know that. I suppose if we had another species to compare ourselves to, then we'd have an answer...but we don't. So I guess it's up for debate.

    You could make the argument we were lucky societies were created that promoted this level of learning and discovery...but since those societies have been created so many times, who's to say that this kind of culture wasn't inevitable?

    Personally, I think that it was always a matter of time before Man made technological advances. Again, our brains haven't changed since we became Homo Sapiens, so the capability for such development has always been there. Call it luck if you like, but I don't see it that way.
  12. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

    No, some other people would have showed up and conquered them.

    The point is, we have a sample set of 1---who's to say our advancement has been slow, fast or typical?
  13. madanthonywayne Morning in America Registered Senior Member

    So many times? The industrial revolution occured only once and was exported to other societies.

    Consider China, who had a fairly advanced but stagnant society for thousands of years. We got gunpowder from them, then show up a few years later with gunships demanding they do as we say.

    Many societies simply do not foster innovation.
  14. Dinosaur Rational Skeptic Valued Senior Member

    There have been quite a few threads which discussed the existence of intelligent life elsewhere in the universe.

    At these threads, I seem to be the sole skeptic about the frequency of occurrence of intelligent life.

    The Fermi Paradox does not surprise me becuase I expect intelligent life to be a rare phenomenon.

    Most who post on this issue seem to forget (or no know) that a galaxy has a habitable zone.

    If a solar system is too close to the center, there is too much harsh radiationn hostile to living creatures. Closer to the center, stars move faster, else they would be sucked into the core. Planetary orbits cannot remain stable for the billion or so years required for life to develop. Intelligent life seems to require a stable orbit in the habitable zone of a soar system for 4-5 billion years, which is not possible closer to the center.

    A solar system too far from galactic center forms from gas clouds which do not include enough of the heavy elements required by living creatures.

    As I have posted elsewhere, it is possible that we are the first and only intelligent species in our galaxy. At best intelligent life is a rare phenomenon.
  15. MarcAC Curious Registered Senior Member

    Also take a look at the responses to this conjecture.

    Studies have suggested that we are not even in the part of the habitable zone most favourable to our development!

    SETI has only looked out to about 50 ly within the ~7000 ly wide habitable zone, which, going around the galaxy, contains about 10 billion stars.

    Let us not forget that once a civilization evolved to a certain point, solar systems do not constrain them, hence Fermi's Paradox.

    That's why we shouldn't readily dismiss accounts of UFOs as possible extraterrestrial engineering.

    We just can't conclude, based on what we've observed, whether intelligent life is rare or not.

    As posted previously, there are just too many possibilities.
  16. Oniw17 ascetic, sage, diogenes, bum? Valued Senior Member

    I've thought about that a lot; it would really suck if that turned out to be true. I've also thought that sooner or later we will have developed all of the technology possible(somewhat related to the OP). It's only a matter of time until that happens, right?
  17. glenn239 Registered Senior Member

    If it were a moon in orbit around a very large planet, could the magnetic field of such a giant help protect life on the moon?

    Saw an article in Air International on new aviation designs last month. Those hillbillies must have been geniuses, because the future looks suspiciously like what was being reported from the late 1940’s onwards.
  18. orcot Valued Senior Member

    Ganymedes has it's own (weak) magnetic field with only 3% of earths mass
  19. MarcAC Curious Registered Senior Member

    Moons around giants are interesting candidates for lifeboats indeed.

    From what I recall, though, the radiation environment which is a product of those same magnetic fields can sterilize any exposed life forms.

    That's why they would look for remains of lifeforms on Europa's surface, and living creatures, below the surface, protected by the ice.
  20. Ophiolite Valued Senior Member

    No. I also fit this category. At least I do not share the view held by many that in a large Universe, or even a large galaxy, intelligent life is inevitable.

    Aside from the reservations you have as to galactic habitable zones I also doubt how readily intelligence develops. Creatures of sufficient complexity, appropriate anatomy and adequate metabolism existed for two hundred million years before intelligence emerged. That has the smell of chance about it.

    That said, I should also not be surprised to find that life, intelligence, and what comes after, are all inevitable emergent properties of this Universe. I just need some better data before I see that as probable.
  21. KennyJC Registered Senior Member

    It's a frustrating subject for me. Our best telescopes still only show nearby stars as dots of light and we really can't explore anything, and that's only in our galaxy. We struggle to even get on neighbouring planets!

    Jimi Hendrix's song 'Up From the Skies' sums it up for me...

    So where do I purchase my ticket,
    I would just like to have a ringside seat,
    I want to know about the new Mother Earth,
    I want to hear and see everything,
    I want to hear and see everything,
    I want to hear and see everything.
    Aw, shucks,
    If my daddy could see me now.

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  22. orcot Valued Senior Member

    1616 galileo's jupiter and it's moons

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    simplefied image of todays look at jupiters moon IO 1995

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    verry first exoplanet 1995

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    ... call me a optimist but the next image won't take 400 years
  23. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

    Well, I guess it depends on what ``fundamental'' means. That is, if we really do live in four dimensions, and c really is a fundamental constant, then there's no real way around it. EVERYTHING real moves at a speed less than or equal to c. Period. The only caveat is that virtual particles CAN travel faster than the speed of light, which is predicted by QFT. But these are virtual particles and are not observable.

    If we live in some higher dimensional universe, then it may be possible to transmit information (and in principle, people) through the higher dimensions, but I can't even begin to imagine that being realistic---one would have to understand gravity very well, so that you could transmit information encoded in gravity waves (probably in a similar manner as the way we transmit messages through electromagnetic waves). Gravity is typically the only force that isn't confined to four dimensions in these proposals, so moving in a higher dimension would essentially allow one to hope around our four dimensional universe instantaneously, and at will.

    The other possibility that I am aware of is wormholes. Wormholes are basically a loophole in GR, but it's not clear if an observer can survive the journey through a wormhole (I just remember this result, and can't cite a specific paper---sorry!).

    Besides, there are other barriers to ultra fast interstellar travel. Suppose you are traveling between two stars and want to do so very quickly. In space, it takes you just as long to speed up as it does to slow down, so you could only accelerate for half of the journey.

    Also, suppose you ARE travelling at very close to the speed of light and hit a speck of dust. The resulting collision would probably destroy your space craft. Besides, how are you to know if an asteroid happens to pass your path? You can't, because any signal you send would be at the speed of light, and by the time you got the signal it would be too late (you can check this quickly on a scrap of paper).

    Finally, one of the reasons that astronauts can only spend a limited amount of time in space is cosmic radiation. Typically, it is the Earth's magnetic field that keeps us safe from cosmic rays---you can see this in action when you look at the Northern Lights. In a space craft outside the protection of the Earth's magnetic field, astronauts are exposed to deadly levels of cosmic radiation, and may mean that even if you got to the nearest star, you'd have some pretty nasty cancer by the time you got back.

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