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A different universe

  1. Nov 4, 2015 #1
    1. Imagine a universe where electrons and protons have positive and negative electric charges, respectively. Could an atom consisting of one electron and one proton exist in this universe?


    2. None.


    3. My first thought was that such an universe already exists (ours) since an atom with a negatively charged proton and a positively charged electron is antihydrogen, which does exist but is very rare.
    However, my prof also wrote me the following:

    Think about whether a positive electron and a negative proton can form an
    atom in this different universe. Question does not mention anything about
    antimatter.
     
  2. jcsd
  3. Nov 4, 2015 #2

    BvU

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    Hi motley,

    What would change in the physics ?

    Another inroad: what if we had used the name positive for the charge of an electron and negative for the charge of a proton ?

    How do we know at all that an electron has negative charge and not positive ?
     
  4. Nov 4, 2015 #3
    Hi BvU!
    Thank you for your answer.
    I'm inclined to say, that the fact that an electron is charged negatively and a proton positively is pretty arbitrary and that the physics wouldn't change if I swap their values.
     
  5. Nov 4, 2015 #4

    BvU

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    I'm inclined to agree.
    Physics needs an attractive Coulomb force and that is conserved under this swap of charge.

    Don't even smell a rat here. Hope I'm not too naïve. But if we're wrong, I'd sure like to be put right !
     
  6. Nov 4, 2015 #5
    Thank you very much! I will let you know once my homework's marked.
     
  7. Nov 4, 2015 #6
    Oh btw. Electrons being negatively charged is just something that's been decided, right?
     
  8. Nov 4, 2015 #7

    BvU

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    Exactly. They needed something to distinguish one from the other.
     
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