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|    sci.physics.research    |    Current physics research. (Moderated)    |    17,516 messages    |
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|    Message 17,460 of 17,516    |
|    Stefan Ram to All    |
|    Where's "left"?    |
|    02 Aug 25 21:57:54    |
      From: ram@zedat.fu-berlin.de              Read too many physics books, and you might forget where "left" is!               I tried to find it out, but neither AI nor the web gave me        the answer. Someone already must have figured that out, but        I was not able to find it!               So, from several notes in the web and my own guesses, I put        together this attempt. Please check it! Is it correct?               My attempt:               Cool down cobalt-60 as much as possible (near absolute zero).               With a strong magnetic field, align the nuclei.               We have two directions:               A: from the north pole of the magnetic field to its south pole, and        B: from the south pole of the magnetic field to its north pole.        (B=-A)               That direction of A and B into which more electrons are emitted        during many decays we call the "south pole" of the nuclei.        (This is our definition of "south pole of the nuclei").               Since all nuclei are aligned, let's focus on one nucleus.               An observer now looks at that nucleus so that its south pole is        at the bottom (direction toward his shoes) for him.               The unit vector from the nucleus to the observer is the x axis.        (This is our definition of that x axis.)               Now assume a small macroscopic object at the place of the        nucleus with the same angular momentum as the spin of the        nucleus.               The macroscopic object rotates a bit. Let the x axis be carried        away (rotated around the object) by this rotation until its        projection onto (scalar product with) the original x axis        (unit vector) vanishes (is zero). (Meaning to rotate it by        90 degrees.)               Then, this rotated x axis now points to the /left/ from the        point of view of the observer.              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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