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Synthetic, exotic particles as a sign of extraterrestrial life

  1. Jul 10, 2007 #1
    Would obviously synthetic particles traveling through space be a choice to broadcast the presence of life? Likewise, say we detected an unnaturally large cross section of an otherwise rare particle impinging upon Earth; might that vestige be a purposeful indication of extraterrestrial civilization?
  2. jcsd
  3. Jul 10, 2007 #2
    Sure : if we detected tv broadcast from another galaxy, an astrophysicist could call that "synthetic particles" or "unnaturally large rates". :-)

    I think I miss you points for some reason on "synthetic" particles. :confused:
  4. Jul 10, 2007 #3


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    A torn three armed nylon shirt adrift in space would be an obvious sign of aliens.
  5. Jul 10, 2007 #4


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    How would someone know they're synthetic and not naturally occurring elsewhere? What would make them "obviously" synthetic?
  6. Jul 10, 2007 #5
    Particles would much more readily be accelerated to speeds near that of light than macroscopic objects. Their uniqueness would be analogous to the often considered patterns of photons, like a signal of prime numbers or an organized alien transmission.

    By "synthetic" I mean unnatural, that which would only arise as the product of intelligent beings. Consider Technetium (element 43), not occurring except rarely outside of the laboratory and justified as such by atomic physics.
    Last edited: Jul 10, 2007
  7. Jul 11, 2007 #6
    In fact, I still understand that what you propose here is the way a particle physicist would describe any sign from an alien planet.

    For definiteness, say the "synthetic" particle they use is the "alienon". We know that in the range 10 MeV to 100 MeV, there is in average 0.5 alienon every other millenium per square kilometer coming from a certain angle (direction). Now suddenly we detect in this range of energy zillions of alienons per second per square meter coming from a definite galaxy ! Sure enough something is going one there. It would of course take a while before astrophysicists would appeal to the alien hypothesis.

    But, in a particle physics language, there is no difference (in principle) between this scenario and the detection of alien television broadcast. The detection of an alien television broadcast would correspond to an excess of photon (radio waves) in a certain energy range (wavelength) coming from the alien planet. Before we would really conclude this is an alien signal, we would need to be sure that some information has actually been encrypted in it.
    Last edited: Jul 11, 2007
  8. Jul 11, 2007 #7
    Agreed. As a possible sign of life in outer space, there would be little difference with the "alienon" and particular electromagnetic broadcasts. However, I have never heard of a human attempt to detect a typical spectrum of other than photons as an indication of life elsewhere. I guess such a search for exotic particles would be less practical (or searching for three-armed shirts much less practical) than searching for E-M waves, so our money is best spent on the last.
  9. Jul 11, 2007 #8


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    :rofl: :rofl: :rofl:
  10. Jul 11, 2007 #9
    I would have thought that the only reason a particle can be synthetic is because it is inherently unstable and radioactive, otherwise it's bound to exist somewhere in nature. With that in mind wouldn't any weird particles beamed to us decay before they got to us? I guess you could accellerate them very close to the speed of light but if you have the energies to do that why not just beam a radio message saying "oi! you're all fat" or something similarly non-natural?

    Also what are our chances of actually realising these particles are synthetic? I'm assuming they'd have to travel fast for communication to be remotely meaningful so wouldn't they just go ping as soon as they hit our atmo?
  11. Jul 12, 2007 #10

    jim mcnamara

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    This whole idea, is, um, well.... It is funny though.

    Let's go, pretend we are aliens:

    Assume 200 billion stars in the Milky Way. Assume 30% are near the sun's
    sequence - F, G, K stars

    Leaves 60 billion star systems with possible life on them. Exclude multiple
    star systems and maybe we get 10 billion possible star systems kinda like

    A three armed T-shirt made of alien_nylon has mass: 100g
    (aliens wear size xtra-xtra small)

    So we want to place just one T-shirt (where T stands for triarm I guess) in
    each star system so another alien can find it floating somewhere in all of
    vastness of the quadrillions of cubic kilometers in the star system.

    So, we need 100g x 10^10 of alien_nylon. Or 10^9 Kg of alien_nylon.
    DuPont makes 5.5 million tons of "earth nylon" per year. So we need
    something like years+ of production of alien_nylon by the
    AlienPlastics, Inc. company.

    All of this just to leave one T-shirt in reasonable star systems -- where
    they would be statistically almost impossible to find.

    "I love this plan - let's do it." - would be the response of our alien
    friends. Until they found out about distribution costs....
    Last edited: Jul 12, 2007
  12. Jul 12, 2007 #11


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    I was thinking something much simpler. Bob & Madge Alien are driving their RV star cruiser on a vacation to visit the kids. Bob is looking anxiously through the clothes hamper, under the bed, the closet floor, etc... for his favorite Intergalactic bowling team shirt.

    Bob: Madge! have you seen my Intergalactic bowling team shirt?!?

    Madge: That ratty old torn thing? I threw that out in the last galaxy we went through.

    Bob: Madge!!! That was my LUCKY shirt!!!!
    Last edited: Jul 12, 2007
  13. Jul 12, 2007 #12
    Argon4 - "Thanks for the shirt, fellow Galaxian, but I can't get my head through the neck hole!"

    Xenon3 - "What the heck's a neck hole - or a head, for that matter?"
  14. Jul 12, 2007 #13


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    :rofl: Loren, you have a great sense of humor. :approve:

    WHO MOVED THE SMILIES!!!!!????:devil:
  15. Jul 12, 2007 #14


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    Most unstable particles could not survive the journey through millions of light-years before decaying, even when accelerated to a significant fraction of the speed of light. The decays would push the particles far enough off-course (due to the conservation of momentum) that they'd never arrive at their intended destination anyway.

    Futhermore, charged particles would be a very bad idea. The universe is full of enormous electromagnetic fields, and the distances are vast. Shooting charged particles through millions of light-years of space would be like shooting an arrow through a hurricane.

    Also, the detection of a stream of particles would be much more difficult than the detection of electromagnetic radiation. I don't know why any intelligent civilization would attempt such communication, when massless, uncharged, non-decaying particles which necessarily travel the speed of light are so readily available.

    - Warren
    Last edited: Jul 12, 2007
  16. Jul 12, 2007 #15
    You just gave me a great idea for my next prank. Now all I need is a seamstress and a stealth spaceship.
  17. Jul 12, 2007 #16
    What do you all think about the possibility of gravitational radiation, deviating from quadrupolarity, being an artificial indicator of advanced extraterrestrials?
  18. Jul 12, 2007 #17
    Perhaps I should rather have asked about the possibility of using gravitational waves in the manner of electromagnetic waves (frequency, polarization, magnitude, etc.) as an artificial indicator of advanced extraterrestrials.
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