Why is the Universe electrically neutral?

lpetrich

That's a conundrum that I've seen posed -- certain people have claimed that it's very improbable.

But here is what I think is a plausible solution. If the Universe originated from a quantum fluctuation or something similar, it would have to have originated as a gauge singlet. Being a gauge singlet means having zero electric charge, thus implying that the Universe is electrically neutral.

Simon Bridge

Which changes to the question of why it has to be a gauge singlet of course. Discovery that the Universe is not electrically neutral would mean that the gauge-singlet idea of the creation of matter is wrong and we'd have to come up with something else. So - is this a strong argument?

"Certain people" would be the "Electric Universe" and "Plasma Cosmology" crowd?

Some discussions into why it is likely that the Universe is electrically neutral:
http://www.physicsforums.com/showthread.php?t=215189

The question of how it came to be that the Universe is charge-neutral on the large scale is quite deep ... a simple look:
http://hyperphysics.phy-astr.gsu.edu...stro/wcep.html
... gives some of the idea.

lpetrich

In post #39 that thread, xantox proposed that the Universe is electrically neutral (total charge = 0) because of gauge symmetry.

I think that that's another version of the gauge-singlet idea.

That's because one can always find a gauge-symmetry operator that can transform one member into another of an irreducible-representation gauge multiplet. Only for a singlet is there only one member to choose from.