Any aliens out there?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by John J. Bannan, Jun 27, 2007.

  1. John J. Bannan Registered Senior Member

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    Seems pretty unlikely that we are going to detect the transmissions of an alien race from Earth. Even if there were an alien race out there, for how long would it be emitting radio waves? 100 years, tops? We probably couldn't even recognize the radiation it was transmitting - presuming they were even transmitting radiation. Better chance the aliens would discover us before we discovered them. Plus, aren't these signals going to be so incredible weak that we wouldn't catch them anyway? Isn't this just a colossal waste of time?
     
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  3. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    John:

    This is more in the line of sci-fi, but I'll weigh in once on the topic.

    If we presume that other solar systems somewhere in the universe [or even somewhere else in our own galaxy] evolved life, the likelihood that such life forms are at our current stage of evolutionary development is miniscule. It is far more likely that such life forms are at an evolutionary development stage that is 100s of millions of years less advanced [i.e. still at a bacterial stage, or even primitive multicellular stage], or 100s of millions of years more advanced; this due to the fact that stars have lifetimes of billions of years, not millions.

    If less advanced, of course we won't hear from them.

    If more advanced [and presuming they survive beyond an early technological stage such as we have here on Earth], their technology would be highly sophisticated.

    With a highly sophisticated technology, millions of years more advanced than ours, one could invision that storage of energy might involve magnetic bottles containing protons and anti-protons, which would be fed into a converter.

    With such an energy delivery system, travel between stars in galaxies, or even between galaxies, becomes feasible. Such energy delivery system, coupled to an excellent thrust system, would allow for near-light-speed travel. The traveller would not age significantly, due to relativistic effects [though it would leave behind everything it had known], but would be capable of reaching planets such as Earth.

    Indeed, one might even envision that such advanced technology might have evolved a very advanced system in which to store its knowledge and memories; i.e. a super super-computer, that would shuttle to various solar systems. Also, the original bio-form of life could be carried along [aliens], to have 'first-hand experience' with investigating such solar systems. Such original bio-form might travel in a unicellular stage, and upon arrival at a decent solar system for investigation, incubate the unicellular stage and "raise an alien child" to adulthood, feeding it memories from the master super super computer. This could be aided by robots, of course.

    To me, this seems far more plausible of a contact method than sending out an electromagnetic signal from an original home planet, and waiting for millions of years to see if there is some kind of response.

    Anyway, as I said, this is more along the lines of sci-fi speculation, but I agree, I doubt that we'll ever detect an electro-magnetic signal from a distant civilization - - to me it seems that it is far more likely that "they" [if they exist] would send "someone" here at near light speed; though that "someone" would not be able to "report back" to its civilization of origin.

    Regards,


    Walter
     
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  5. John J. Bannan Registered Senior Member

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    I agree. Moreover, wouldn't an advanced civilization have the means of detecting us from a distance - instead of actually having to send someone here? Wouldn't they be the ones who initiate contact? The fact that they haven't is a pretty good case for their not being any - at least any who care enough to bother. What we are really looking for is a needle in the haystack. Alien life that just happens to be about as advanced as us. Good luck finding that in this galaxy. If they exist, they are probably way to distant for us to detect.
     
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  7. Orleander OH JOY!!!! Valued Senior Member

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    What if we are the most advanced out here? Someone has to be, why not us?
     
  8. GeoffP Caput gerat lupinum Valued Senior Member

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    There are no aliens out here.

    I mean there.
     
  9. John J. Bannan Registered Senior Member

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    We are really quite ignorant of the probabilities of alien life, let alone the stage of advancement of said life. There are a whole heck of a lot of stars out there not to believe there is alien life somewhere. Could we be the most advanced? Sure. But how do you gauge that possibility?
     
  10. Orleander OH JOY!!!! Valued Senior Member

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    How do you gauge the possibility of life on those other planets?
     
  11. John J. Bannan Registered Senior Member

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    Easy. Whole lot of stars. Whole lot of planets. Very high probability of life somewhere besides here.
     
  12. Orleander OH JOY!!!! Valued Senior Member

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    Yes, but what makes any of that life intelligent?
     
  13. John J. Bannan Registered Senior Member

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    On what percentage of planets that harbor life is that life intelligent? Don't know. Still, there are a heck of a lot of planets.
     
  14. BobtheBuilder Registered Member

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    Yeah. Given the near infinite number of planets, I would assume the probability of there being other intelligent life to be itself nearly infinite. Say the probability is something like 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 to 1. No matter the number I throw out, I think we can safely assume there are way more planets. There is thus probably intelligent life.
    (btw, I don;t know jack about any of this.)
     
  15. fishtail Registered Senior Member

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    No one gives a thought to time, a civilisation could come and go in 50,000yrs
    even less, if we received a signal from an alien race, that race may have been dead for years.
     
  16. Fraggle Rocker Staff Member

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    There's no reason to be pessimistic and presume that there is no other intelligent life. As for the difficulty of disparate societies maintaining substantive contacts with each other, much less federating into a galactic civilization, we assume that is impossible because Einsteinian physics is correct and there's no way to exceed the speed of light.

    We've been wrong before. However, the scenario we're dealing with assumes that there are other people wrestling with the same problem, and statistically some of them are probably far more advanced than us. So why haven't we heard from them, why haven't they sent explorers to trade cultural motifs, occupy us, eat us, or whatever? They've got nothing to fear from our primitive technology.

    Sci fi offers several reasons.
    • They haven't completely defeated Einsteinian physics. They have interstallar travel but it has its limits and they still haven't gotten out here to our solar system. We are out in the galactic boondocks after all. If they're a thousand light years away it will be 900 years before our first radio waves reach them. They don't know we're here, a la Farscape.
    • They believe in the Prime Directive. They don't want to interfere with our development of our own civilization by contaminating it with theirs, a la Star Trek.
    • They haven't found that contact with more primitive civilizations is worth the effort. We have nothing to offer them.
    • They had a galactic war and killed themselves off a million years ago. When we get out into space we'll find their artifacts everywhere and learn to use them without understanding how they work, a la Babylon 5 and Stargate SG-1.
    Science offers a couple of other hypotheses, which have not been disproven.
    • Einsteinian phyiscs is correct, there is no FTL travel. We're all limited to generation starships and communications with generation time lag.
    • Intelligent life exists but is exceedingly rare. The nearest civilization may be four galaxies away. There are still uncountable numbers of us, but there's no way we'll ever find each other.
    • Both of the above hypotheses are correct. There could be many advanced civilizations right here in our galaxay and it will take us a loooooong time to find each other.
     
  17. iceaura Valued Senior Member

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    Negative results from a scan for radio-producing beings in the fairly near galactic neighborhood would not be a "waste of time". They would tell us some of what isn't so, and reject whole categories of otherwise teneble conjectures.

    Might be there are better uses of money and time, in somebody's judgment, but the worth of the project does not depend completely on obtaining positive results. And subsidiary, accidental discoveries in unrelated matters are always possible, jsut from the looking.
     
  18. orcot Valued Senior Member

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    true it never harms to show interest in the neigbours
     
  19. glenn239 Registered Senior Member

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    This implies that they’d be motivated to talk to us….what’s in it for them other than our sterling conversational skills and charm?

    The proper evolutionary conditions.

    There is no way to exceed light speed, but nothing about our understanding of the laws of the universe rules out the possibility that we can’t approach it. Because of time dilation that means it might take an advanced civilization only a few weeks or a month to reach us, from their perspective.

    If they’ve been around for millions or billions of years, they’ve had plenty of time to snoop out the entire galaxy even at sub-light speed. If they are here, they ain’t talking, and that means that at best they are tolerating us.
     
  20. Fraggle Rocker Staff Member

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    But only from the perspective of the people on the spacecraft. From the perspective of the people they left back on their homeworld, that ship will have been gone for thousands of years, or tens of thousands, before it reports back. If that was our planet, the ship and its crew would be a myth by that time if they were remembered at all; their link with civilization would be gone. There is no "contact" between civilizations when there is a lightspeed lag measured in millennia. Sure, we'd be able to trade literature and other cultural artifacts--with people who died when we were hunter-gatherers. This is not the makin's of an interstellar civilization!
    Has anyone done the math? Again, suppose it was us. Those ships that can make the trip in a few weeks or months will be hideously resource intensive. The ones that travel at more affordable speeds will need to be monstrous generation starships, which are also hideously resource intensive. How many starships of either type could earth build and launch per century? How long will it take that slow trickle of ships to explore the whole galaxy?

    Bussard ramjets are theoretically capable of high speeds without needing to carry a lot of fuel because they burn up the interstellar hydrogen. But something tells me that this technology will simply prove that even the entire galaxy is a finite resource and we'll start running low on interstellar hydrogen. Besides, how long must a ship accelerate on conventional rockets and how much conventional fuel must it burn before it begins to scoop up enough hydrogen to take over the propulsion system?
     
  21. glenn239 Registered Senior Member

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    The ship’s ability to transmit/receive during transit would be curtailed according to time dilation, but would not be completely eliminated. It would depend on how close to the speed of light the ship was travelling and how much more data the aliens could transmit per second than we can.

    From our perspective the time lag between the ship and its homeworld is not a factor because we are not dealing with the world, only the ship. When it gets here they’ve only been journeying for a short period of time to those aboard. How long it appears to take to the homeworlders depends on whether they stay on their planet, or also make voyages themselves. In any case, if the originating civilization is millions or billions of years old, 5,000 years is not that big of a deal.

    Depends on our ability to produce energy and the size of the ship in question. If we assume .99 c to be obtainable, then a scout could reach the other end of the galaxy in about 100,000 years.
     
  22. the Radio Star Banned Banned

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    John,

    You may be interested in the Rare Earth hypothesis. We may be alone.
     
  23. Star_Kindler Registered Member

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    the Radio Star,

    You may be interested in recent news, in which the National Research Council concluded that extraterrestrials may not be recognizable to us initially, because they could exist in totally alien forms in totally alien environments.

    Also, even if Earth-like worlds are RARE, it's impossible that there aren't billions of Earth-like worlds in our universe, when you consider size. Therefore, it seems likely that more than one in a billion would produce intelligent life.
     

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