system
Given the following post, respond as if you're commenting on Reddit:
human
What is the net charge of the universe?

I don't mean a precise answer, but are there more protons than electrons in the universe? Or vice versa?

Or do protons and electrons exist at (or extremely near) a 1:1 ratio, even if not equally distributed in terms of position relative to each other?

From what I understand, a few fractions of second after the Big Bang, energy that had condensed into anything other than stable baryons or leptons (i.e. protons, electrons, neutrinos) decayed into these species, and then the universe cooled and so forth. Neutrons form during fusion when strong-force interactions keep them stable, and electrons are captured by proton/neutron nuclei when things cool from a plasma, e.g. a while after a supernova.

My question is thus, why does it seem as if there are electrons for every proton, and if this is the case, why does this relationship exist? If this is not the case, where do we find the extra particles of the majority species?

Thanks!
gpt
There are several indications that the universe is in fact charge-neutral.  For starters, gravity seems to be the dominant force when dealing with cosmological length scales.  Since the electromagnetic force is much much stronger than the gravitational force, if the universe had a net charge we'd probably see evidence of the EM force acting at large length scales.

Also, if the universe had a net charge, there would be currents associated with these charges that would presumably be observable when looking at the cosmic microwave background (CMB).  However, we do not see evidence of such currents, further supporting a charge-neutral universe.

However, the CMB measurements are from the early universe.  This is not to say that's entirely impossible for the universe to have been charge-neutral in the beginning, then through some physical process gained a net charge some time later on.  Although more than likely, if it was charge-neutral to begin with, it'll stay that way.