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Communicating with an alien race

  1. Jul 29, 2008 #1
    Not sure if this has been asked here (searched but couldnt find anything), but I thought this was an awesome question (heard in a feynman lecture)

    If you were communicating with an alien race, with no visual lines of communication (only audio) how would you explain left and right, so that it correlated with our own definition of it?
     
  2. jcsd
  3. Jul 29, 2008 #2

    mgb_phys

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    Re: left/right

    It's worth thinking about - especially if you allow the alien to be made of anti-matter, so particles can have the opposite charge.

    (hint: there is a physical effect which isn't symetric - but it took a long time to find it!)

    ps. for the answer see here http://www.lbl.gov/abc/wallchart/chapters/05/2.html but not until you've thought about it.
     
  4. Jul 29, 2008 #3
    Re: left/right

    you sound as if you already know/knew the answer? :)

    I dont know if these forums have a way of hiding info (spoiler tags or something)

    but in case this has not been posted here, and people have no seen it, Itd be cool to let this sit for a bit for people to think about. I know I had a blast thinking about it.

    *edit*
    ah, a link works :)
     
  5. Jul 31, 2008 #4
    Re: left/right

    Some organic molecular compounds have significant difference in their chemical/physical properties depending on whether the molecule (otherwise with exactly the same atoms and chemical bonds) is shaped clockwise or counterclockwise.

    Perhaps this can be used, if the two races have some shared knowledge about such compounds.

    Check this out:

    http://en.wikipedia.org/wiki/Amino_acid_dating

    "Life requires a certain composition AND shape of amino acid molecules in order to complete their function. Living organisms on earth keep their amino acids in the L position, with a notable exception found in certain bacterial cell walls, and their sugars in the D position. When the organism dies, control ceases, and the ratio of D/L moves slowly toward equilibrium (racemic). Thus, measuring the ratio of D/L of a sample can allow calculations of how long ago the specimen died."
     
  6. Jul 31, 2008 #5

    mgb_phys

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    Re: left/right

    The experiment assumes you are only in 'telegraph' (would be email today) contact, you can't send them a sugar cude and say - this is left handed.

    Why biological reactions use the let handed form isn't totally understood but it's thought to be pure chance. Which ever self-catalysing chemical reaction product eventually became the grandparent of all life happened to be left handed. If life started again or somewhere else it might just as easily be right handed.

    One of the interesting results if we find bugs on titan (or wherever) is will they be left-handed?
     
  7. Jul 31, 2008 #6
    Re: left/right

    I thought the same thing, and ended up buying a couple papers on what makes life left handed. Pretty cool papers. I figured if we always have a spleen on the left side, SOMETHING is causing that, if you trace it back far enough, you will have it!

    but as mgb_phys said, it was a choice made early in our development (as life) that was due to something. (random does not actually exist :tongue:) whether or not that thing was very small or somewhat bigger is another issue.
     
  8. Jul 31, 2008 #7

    Integral

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    Re: left/right

    This topic is more about how we communicate then physics. Therefore I have moved it to the social sciences forums.
     
  9. Jul 31, 2008 #8
    Re: left/right

    how we communicate?

    if you ignore anti-matter there is a solution to defining left/right (chirality) and its very much based in physics. The question was issued in a quantum physics lecture from richard feynman.

    But, your forums, your choice
     
  10. Jul 31, 2008 #9
    Re: left/right

    Okay, before I can come up with an "answer", what are the rules about language. Do we share a common language, say math, or is communication in english allowed?
     
  11. Jul 31, 2008 #10

    mgb_phys

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    Re: left/right

    In the original thought experiment you can communicate perfectly (well on Star trek everyone speaks English!) but you can't pass samples and don't have other reference in common - you can't see the same constellation for instance.
     
  12. Aug 1, 2008 #11
    Re: left/right

    I think an analogy of the interwebs would suffice. This can make things even more confusing for some though as they start using pictures and such, but how would you tell the aliens how to assemble the picture on the other side?
     
  13. Aug 1, 2008 #12
    Re: left/right

    Also, by "correlated with our own definition" would this mean that we are just trying to understand eachother when we both have something to our left we can say that or that we are using the same interstellar directions?

    (Sorry for being particular, I'm just trying to understand the question fully)
     
  14. Aug 2, 2008 #13

    nrqed

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    Re: left/right

    There is a left-right asymmetry in the fundamental laws of physics. This is called CP- violation.

    In his book "The Ambidextrous Universe", Martin Gardner explains how this could be used to define left and right when communicating with an alien species.
     
  15. Aug 4, 2008 #14
    Re: left/right

    yes

    as for the cp violations, if there is an answer there must be something at the fundamental level that denotes left/right, I was thinking a somewhat higher level "experiment" they could run to show it :)
     
  16. Aug 4, 2008 #15

    DaveC426913

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    Re: left/right

    Rudiementary. They did it for the SETI message. You send your message as sequences of prime numbers, say, 29 dicerete bits in 37 groups. Whether they have math like us or not, there's only two ways to represent this sequence of signals: one looooong sequence of 1073 discrete bits, or a grid of 29x37. One yields nothing interesting, the other yields some very intriguing correlations between otherwise discrete bits.

    I think a universal sign of intelligence is the ability to root out patterns (is that a tigradonoid in the bushoid over there?)
     
  17. Aug 4, 2008 #16
    Re: left/right

    What is the point? We can assume with virtual cetainty that any species we come in cantact with will not know english and that we will likely have to communicate with them in some other fashion(likely mathematics as Dave points out). With out the ability to send pictures or any such thing there would be no way to 'teach' one another our respective languages. 'Right' and 'Left' are rather ineffecient descriptors for communication to begin with.
     
  18. Aug 4, 2008 #17

    DaveC426913

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    Re: left/right

    Feynman seemed to think it was important. :rolleyes:
     
  19. Aug 5, 2008 #18
    Re: left/right

    If you can communicate "perfectly", then you also talk about specific aminoacids without the need to pass samples.

    The fact that their biology or the lifeforms on their planets may be working differently however stands as an obstacle.
     
  20. Aug 8, 2008 #19

    George Jones

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    Re: left/right

    Let me expand a bit on the original post and some of the subsequent posts.

    The main question of the thread stated explicitly is "Are the laws of physics left/right symmetric?" This is a scientific question that can be determined by experiment.

    Before 1956, the answer to the question was generally thought to be "Yes." Puzzling experimental results that could be explained by an answer of "No." caused physicists to reexamine this question. Lee and Yang made a systematic survey of the literature and determined that for weak nuclear interactions there was no evidence one way or the other. They also suggested experiments to directly test this, and Wu, with help from others, performed one such experiment. The answer was found to be "No." and Lee and Yang won the 1957 Nobel in physics "for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles."

    In 1961-62, Feynman taught the Cal Tech first-year physics course, and, wanting to excite the students with current research, he talked about the meaning and consequences of having a law of physics that is not left-right symmetric. Feynman outlined a simplified version of Wu's experiment, and told the students that by communicating this outline to distant aliens, one could communicate the idea of left and right in an unambiguous absolute way. This would be impossible if the answer to the original question had been "Yes.", as was expected before 1956.
     
  21. Aug 8, 2008 #20

    LowlyPion

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    Re: left/right

    Is the answer thought to not be applicable in a region of the universe if it were of antimatter? Or is such a region discounted as a significant possibility?

    Edit: And oh by the way thanks for the explanation.
     
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