Is active SETI dangerous?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Zephyr, Aug 14, 2007.

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  1. Zephyr

    Zephyr Humans are ONE Registered Senior Member

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    http://lifeboat.com/ex/shouting.at.the.cosmos

    "Active SETI" is the broadcasting of high power messages into space in the hopes of attracting the attention of . . . someone. Does that seem wise to you?

    Personally, I think any sufficiently advanced civilisation which wanted to contact us, for benevolent or malevolent reasons, would have done so already.
     
    Zephyr, Aug 14, 2007
    #1

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  3. cosmictraveler

    cosmictraveler Be kind to yourself always. Valued Senior Member

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    It will take those transmissions over 5 light years to reach any other nearby star that COULD contain life. So that will sometimme in a few thousand years from now so we won't have to worry, those coming along around then will have to be prepaired though.:shrug:
     
    cosmictraveler, Aug 14, 2007
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  5. Fraggle Rocker

    Fraggle Rocker Staff Member

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    This question has been raised in a number of threads, they shouldn't be hard to find.

    Put your mind at ease. With technology we don't even have yet, but we can envision, it will take a spacecraft from earth around 80,000 years to travel to the nearest star. You can imagine any type of improvements you care to, and make that ship faster, but you still run into: 1. the lightspeed limitation; 2. the ability of an organism to endure excessive acceleration; 3. the energy requirements. Perhaps somebody out there has found a way to travel between our sun and Alpha Centauri ten times as fast and can do it in only 8,000 years. It would have to be a generation starship. That means it has to be big enough to hold an entire city, a culture that will sustain a civilization for that long without breaking down into the Stone Age. Can you imagine their people, their leaders, devoting the enormous effort and other resources to such a low-payoff project? BTW that is just about the total length of time our civilization has been in existence--AND--we already know there's nothing interesting orbiting Alpha Centauri so we have to go past it to the next star.

    Nobody is going to send a fleet of such ships in one direction, hoping to find an inhabited planet to exploit. If they can afford to even build a fleet, they'll send the ships in different directions and maximize the probability of finding something. By the time one of them gets here, it will be so out of touch with its homeworld that it will not be a "representative" of anything. Civilization back home has advanced by several millennia. Sure that one ship could be carrying a planet-busting bomb, if they've managed to invent one, and if they're willing to devote so much of the ship's capacity to that one payload, but that's about the only way one shipload of aliens could "conquer" earth and it would be a hollow victory. I'd expect them to be glad to find somebody to talk to after all that time in the lonely void, even if they were the galactic equivalent of the Spanish conquistadores.

    And then there's the issue of signal attenuation. IIRC, on another thread here in Cosmology, a member stated that if there were a planet just like ours orbiting a nearby star, our own SETI apparatus is not powerful enough to pick up its transmissions. Interstellar communication is not quite as handy as it looks on Star Trek.

    It will be very difficult for anyone to know we're here and aim their ships at us. Even so, it will be a quixotic effort to actually send just one ship to our planet. And it will be impossible beyond a reasonable doubt for the people on the ship to threaten our civilization.
     
    Fraggle Rocker, Aug 14, 2007
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  7. Captain Kremmen

    Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    If space people did arrive they would probably see us as pests.
     
    Captain Kremmen, Aug 14, 2007
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  8. draqon

    draqon Banned Banned

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    Zephyr...added to the SETI info...NASA sent human DNA information!!!

    I mean thats like an opportunity for aliens to make genetic weapon. Just send a small meteor to Earth with a virus, it will spread across species, and get to the humans.
     
    draqon, Aug 14, 2007
    #5
  9. cosmictraveler

    cosmictraveler Be kind to yourself always. Valued Senior Member

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    We currently make enough new forms of bacteriologicle viruses to destroy ourselves, so that's not much to worry about. We wiil probably wipe out humanity ourselves before any aliens ever get here.
     
    cosmictraveler, Aug 15, 2007
    #6
  10. draqon

    draqon Banned Banned

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    not on my watch.
     
    draqon, Aug 15, 2007
    #7
  11. cosmictraveler

    cosmictraveler Be kind to yourself always. Valued Senior Member

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    These viruses are being made by at least 10 different countries, can you watch them all? What if terrorists steal some?
     
    cosmictraveler, Aug 15, 2007
    #8
  12. draqon

    draqon Banned Banned

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    my plan is to run away.
     
    draqon, Aug 15, 2007
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  13. Norsefire

    Norsefire Salam Shalom Salom Registered Senior Member

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    You guys are making the assumptions that any alien species has the same level of knowledge or technology as us. You never know, a species that may be millions of years ahead of us, and can utilize the fabric of space for instant travel (like a wormhole)

    So, a civilization advanced enough could get to Earth within seconds, it's not impossible. Maybe they know something we don't.

    And, if they can get to Earth, the question is, what would they do?
     
    Norsefire, Aug 15, 2007
    #10
  14. cosmictraveler

    cosmictraveler Be kind to yourself always. Valued Senior Member

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    Again let me assure you if they were that advanced why is it they would come to this backward planet? Radio transmissions travel in a somewhat straight line, like your radio stations today operate with. Those transmissions to outer space will eventually hit a solid object to stop their travel. There are many things that are in the space between us and whoever else might be out there so any transmissions will be stopped before being recieved.


    There's also not enough power to get them very far, just like your favorite radio station as you drive away from the stations transmitter you lose their sidnal. So this too will happen to SETI signal.
     
    cosmictraveler, Aug 15, 2007
    #11
  15. Fraggle Rocker

    Fraggle Rocker Staff Member

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    No, we're making the assumption that they're subject to the same laws of physics as the rest of us. e=mc^2, that kind of stuff.
     
    Fraggle Rocker, Aug 15, 2007
    #12
  16. S.A.M.

    S.A.M. uniquely dreadful Valued Senior Member

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    I think the best evidence for intelligent life in the universe is that no one tries to contact us.

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    S.A.M., Aug 15, 2007
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  17. Captain Kremmen

    Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    All the other inhabited planets might be very civilised and friendly.
    They might have seen us and just decided to ignore us.

    We are "The neighbours from Hell"
     
    Captain Kremmen, Aug 15, 2007
    #14
  18. Fraggle Rocker

    Fraggle Rocker Staff Member

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    I think we've all been reading and watching too much science fiction. We have a pretty good understanding of how the universe works, and the probablity that we missed something that would make it possible to construct a "space warp," "hyperdrive" or "star gate" is pretty small. Interstellar travel at relativistic velocities cannot possibly be a force for significant cultural--much less political or military--contact. We'll be exceedingly lucky if someone finds a way just to exploit interstellar communication.
     
    Fraggle Rocker, Aug 15, 2007
    #15
  19. Captain Kremmen

    Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    Every generation considers itself as being very advanced in science, and laughs at the folly of previous generations who thought the same.
    Particle physics is only 100 years old, and cosmology half that.

    ......."the probability that we have missed something" may become small after a few hundred years, but it would be a presumptuous claim at the moment,
     
    Captain Kremmen, Aug 16, 2007
    #16
  20. Orleander

    Orleander OH JOY!!!! Valued Senior Member

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    somewhere out there in the universe is the most advanced life ever. What if its us?
     
    Orleander, Aug 16, 2007
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  21. Atom

    Atom Registered Senior Member

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    I agree!!!

    Sry..its not often I get the chance on here

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    Atom, Aug 16, 2007
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  22. Atom

    Atom Registered Senior Member

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    They contacted me but told me to keep schtum..

    ..oooooops

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    Atom, Aug 16, 2007
    #19
  23. Billy T

    Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Not a danger. In addition to the facts about distance/ travel time sparce density of advanced civilians etc. others have mentioned, one needs to recognize that much stronger beacons have been continuously broadcasting that Earth has a civilzation with at least rudimentary technical capabilites for 50+ years.

    I refer to TV transmission. The TV broadcasted energy is a well defined disk tangential to the Earth (no point in sending any energy except locally horizontally) This means that twice every 24 hours the high power TV beam makes a complete circular sweep thru the heavens.

    Nothing SETI can afford to do even comes close the ease of detectivity of these repeating beams. If they are recieved, they aliens will soon be laughing at "I love Lucy." from the 1950s etc. They will obviously easily know the Earth rotation takes 24 hours and less obviously it distance from the star well call "the sun" (by the 365 day cycle of the Dopler moducaltion of the beam frequency.) Program content will tell much about the nature of the Earth's inhabinates, but not what they may want to know most (I.e. do they taste good?)
     
    Last edited by a moderator: Aug 16, 2007
    Billy T, Aug 16, 2007
    #20
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