Big Bang Theory Violates First Law of Thermodynamics

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Harmonic_Subset, Aug 27, 2020.

  1. arfa brane call me arf Valued Senior Member

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    Why compare what an optical mirror does, with what certain symmetries of nature do to particle-antiparticle pairs? Mathematically, reflection symmetries are exact in that the changes in parity always preserve or fix, an orientation. For example, your mirror reflection doesn't change the up direction, your reflection only changes left to right. Mirror reflection is equivalent to a parity transform because direction of motion is reversed, and motion is in one dimension.

    So apparently, CPT is a theorem that says the symmetry of time (except time is a symmetry), is equivalent to the combined symmetries of C and P. So that a proper *reflection* of a clock is a clock of antimatter with hands moving in the opposite sense. Is the antimatter clock showing negative time, though?
     
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  3. arfa brane call me arf Valued Senior Member

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    Furthermore, is T-symmetry even needed, if CP-symmetry is equivalent (in that CP-violations are also T-violations)?

    I've had that article by Robert Adair for some time, and one of the first things that occurred to me, is that the images of Alice and her reflection (taken from Carroll's Alice through the Looking Glass), are just really visual aids; the important stuff is the copper wire and a current with a direction. So the image of a clock and its reflection aren't really important either, other than as visual aids. That is, as long as a direction of motion (or of a magnetic field) are represented faithfully, all the information about individual C, or P, or CP symmetries is also represented.

    The idea is to show how a particular symmetry or combination, is not like a simple optical ("perfect") reflection.
     
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  5. Q-reeus Valued Senior Member

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    P reversal leaves motion in the mirror plane unchanged, motion normal to the plane reversed. It follows that the B field of a circular current loop is unaffected for loop axis normal to the mirror plane, but reversed for axis in the plane. Magnetic moment direction always maintains the same sense wrt loop current spin axis.
    The hands still sweep from lower to higher numerals, so....I'd say....no.
     
    Last edited: Sep 13, 2020
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  7. Q-reeus Valued Senior Member

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    CP violation was first observed in 1964, while actual T-symmetry violation wasn't till 2012. That at least is the consensus position among particle physicists.
    Recall from earlier posts that T-reversal produces faux antiparticles where like charges attract and unlike charges repel. That doesn't happen when applying successively P and C swapping.
     
  8. arfa brane call me arf Valued Senior Member

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    Ok, but if you have a wire loop with an anticlockwise current, hold it parallel to the surface of an optical mirror, the current is anticlockwise in the reflection.

    So the magnetic field will point in the opposite direction in an optical reflection; but that isn't what happens when you reverse the current in a real wire loop, instead the field direction reverses. So P-symmetry fails to be like reflection symmetry and in a P-mirror you see magnetic fields point in the same direction when the currents are parallel to the mirror (which isn't of course, actually a mirror).

    Or take a pair of wire loops, try reversing the direction of the current in one of them, and then seeing if you can arrange the two loops so they correspond to an exact reflection of each other . . .

    And that's just the classical stuff that happens. Particles change from left-handed to right-handed with a reflection, that's a problem for neutrinos though.
     
    Last edited: Sep 14, 2020 at 2:09 AM
  9. Q-reeus Valued Senior Member

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    Yes and consistent with your quote. But given your below comment, perhaps you meant the current is clockwise in the reflection? That would be wrong.
    ??? The B field of a loop current points in every possible direction, but the loop current has one unique magnetic moment axis and sense along that axis. Mirror reflection preserves it for moment M normal to the mirror plane, but reverses it for M parallel to the plane. Which repeats my comment in #103. M is thus a pseudovector.
    As explained first line here: https://en.wikipedia.org/wiki/Parity_(physics) parity inversion is sometimes equivalent to mirror reflection, sometimes not - RH Cartesian -> LH Cartesian.
    Not as straightforward as the simple C & T sign reversals.
    Of course you can - depending on your precise definition of reflection.
    Are we now even remotely on topic?
     
    Last edited: Sep 14, 2020 at 4:24 AM
  10. arfa brane call me arf Valued Senior Member

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    No, you can't.

    Or else, let's see you do it. Parity transforming a current in a wire loop does not result in a reflection, because of the magnetic field direction depending only on the current's direction (clockwise or anticlockwise). That is, it follows the right-hand rule, not the left-hand rule.
     
  11. Q-reeus Valued Senior Member

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    Your challenge in 2nd last line #105 is underspecified for starters. Besides any of that, after so many posts of this fork it's clear conceding error is not exactly your strong suite. This is now way off topic and time to quit.
     
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  12. arfa brane call me arf Valued Senior Member

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    I'm challenging your claim that, depending on how you define reflections, you can reflect a current in a wire loop and this leaves the B field unchanged.

    So I want to see how you do this, because I haven't seen it (ever). Besides reflection does already have a mathematical definition.
    Being off-topic is neither here nor there.

    Mirror reflection does equal a parity transform for ordinary objects like clocks, people, or wire loops.
    Like I suggest, you could try a pair of loops. I guess an identical pair is better but the focus is on what happens to a magnetic field when the current in such a loop is reflected. Then if the current's reflection is equal to a change in parity, does it change the parity of the magnetic field and is the change equivalent to a reflection. (?)

    I've been saying no, it isn't. I'm not really sure what you've been saying.
     
    Last edited: Sep 14, 2020 at 10:26 PM
  13. Q-reeus Valued Senior Member

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    Alright - last post by me on this. Where did I ever make such a claim? Point to the post where I did. You cannot - it's pure invention by you. As for your original underspecified challenge in #105:
    One obvious fulfillment is the mirror image reflection of a current loop whose magnetic moment lies in the mirror plane. The mirror image has current direction reversed. See e.g. illustration here:
    https://www.nist.gov/pml/fall-parity/parity-whats-not-conserved
    Your #105 challenge as it reads allows complete freedom to reorient the loops as desired. It's always possible to arrange any two loop currents of identical magnitude to conform to that above situation. Obviously, if one restricts to where the loop current magnetic moment is always normal to the mirror plane, the mirror image has identical current sense. But you never made such a restriction. Done.
     
    Last edited: Sep 15, 2020 at 3:59 AM
  14. arfa brane call me arf Valued Senior Member

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    So reorient them such that the magnetic field is reflected and so is the current. I say you can't do that.
    The reason is quite simple--the direction of the field around a straight wire is given by the right hand rule. Reverse the current, the direction of the magnetic field reverses but isn't given by "the left hand rule". Hence there isn't a proper reflection.

    That's what Robert Adair says in his article. What do you think I've been saying?
    Again, if it's possible to "simulate" a reflection with a pair of loops, it should be straightforward to describe how, or even post a diagram.

    But, again and once more, it can't be done; it only works if you actually reflect the loop and the current. Wire loops and the magnetic fields around them don't have reflection symmetry, but they do have parity (which, as Adair mentions, fails to be like a reflection). So yeah, I'm a little concerned that you haven't understood what I've been trying to explain.
     
  15. exchemist Valued Senior Member

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    Yes I'm sure you're wise to get out before you blow a fuse. Arfa is, as you say, incapable of conceding a point in discussion. Rather like Write4U in that respect - though without his particular set of obsessions, mercifully.

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  16. arfa brane call me arf Valued Senior Member

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    so there are two morons here (whod'a thot?). Both of them disagree with a scientist who was one of the discoverers of CP-violation at Berkeley.

    He says quite categorically (and I believe him because I know about the right hand rule), that a parity transform isn't like a reflection, the "parity mirror" fails to be like a reflective mirror.

    But Q-reeus says no, supported by exchemist. I guess those engineers need to start over.

    What really gets me is that Q-reeus appears to be agreeing with what I say about wire loops, currents, magnetic fields, reflections and parity transforms. There must be a problem because Q-reeus also appears to point out what's wrong with it; although he doesn't seem to be able to say what the problem is.

    So the conclusion for exchemist is that I don't understand the difference between parity and reflection symmetry. But who cares. I'm happy for people to be ignorant fucks, when that's what they want to be.
     
    Last edited: Sep 15, 2020 at 11:10 PM

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