How would the universe be modified if protons (as we know them) have negative charge and electrons (as de know them) have positive charge.

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    $\begingroup$ This is just a change in convention, so does nothing. $\endgroup$ Commented Sep 8, 2014 at 18:23
  • $\begingroup$ @zibadawa timmy, I mean, as we know them. With their masses, is it possible that protons to be in a cloud of protons? Or if the bigger electron mass in the cloud would make some diference? $\endgroup$
    – El_Mochiq
    Commented Sep 8, 2014 at 18:26
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    $\begingroup$ See C symmetry $\endgroup$ Commented Sep 8, 2014 at 18:30
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    $\begingroup$ You have to distinguish between these cases. If you simply swap charges, nothing happens, because which is which is really just a convention. If, however, you start modifying masses, the whole universe changes in extreme ways. A good phenomenological discussion can be found in phyweb.lbl.gov/~rncahn/www/rmp-18.pdf. The author, Bob Cahn, is a super guy, by the way. $\endgroup$
    – CuriousOne
    Commented Sep 8, 2014 at 18:31

1 Answer 1


As the comments say, it would do nothing if you change all negative charges to positive and viceversa for all know particles. You actually have a real physical example: antimatter (which in most theories behaves just as standard matter but there might be some non-symmetries when you include all particles (it depend on the specific modification of the standard model). Now, if you only change the charge of the electron and the proton, and nothing else, the answer is not so clear: you would need a radically new theory because you will no longer have conservation of charge. The new behavior is not theoretically predictable a priori, only experiments could tell what the new physics would be.


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