Proof That the Universe is Electrically Neutral

[sysreset]

Cosmic rays have been observerd to be 90% protons, 9% helium nuclei, and 1% an assortment of heavier nuclei. With all of these positively charged particles flying around without electrons, doesn't it follow that the universe is not charge-neutral; or, if it is neutral, that charges are separated by cosmic distances?

 

[Wallace]

No, this difference is due to the mechanisms that accelerate different types of objects to different energies. The electrons are there, they just aren't traveling with the same energy.

 

[cadnr]

So why is the universe neutral?

 

[sysreset]

No, this difference is due to the mechanisms that accelerate different types of objects to different energies. The electrons are there, they just aren't traveling with the same energy.

Do you have any sources to back up the assertion that electrons are present in cosmic rays to charge neutrality? My understanding has always been that 99% of cosmic rays are hydrogen and helium nuclei stripped of any electrons of any energy, and are thus positively charged particles. http://imagine.gsfc.nasa.gov/docs/science/know_l1/cosmic_rays.html explains further.

 

[Wallace]

You misunderstood, I agree that cosmic rays are mainly protons or other light nuclei (or high energy photons). The key point relating to this discussion is the sentence 'striped of any electrons'. The electrons still exist, so the Universe is charge neutral, but the electrons don't get accelerated to cosmic ray energies. When I said the electrons are there I just meant they are still in the Universe, not that they are in the cosmic ray flux.

 

[sysreset]

Okay I am with you 100% so far. And the point I am trying to make is not that the universe is not charge neutral (I have zero evidence for that). I am trying to find out if anyone has been able to make an estimate, quantitatively, of the degree of charge separation due to cosmic ray radiation.

For example, let us say that Supernova A is generating cosmic rays. Where are all the electrons and how many of them are there? And how about other supenovi and other sources, etc etc. This must add up to some degree of "non-isotopy" of charge in the universe, if you will. Is the consensus that even this is negligible? How negligible? In human terms, it has to be huge.

 

[Wallace]

The things that produce cosmic rays and distributed evenly throughout space and on average fire the cosmic rays that they produce at the same rate in all directions. Thus for any given region of space the amount of charge leaving due to cosmic rays is equal to the charge entering, so there is no generation of large regions with an overall net charge. In any case the actual amount of material in the Universe is the form of cosmic rays is a minuscule amount compared to the overall density.

 

[cadnr]

Was charge-neutrality of the universe an accident or is it a prediction of Big Bang theory?

 

[xantox]

Was charge-neutrality of the universe an accident or is it a prediction of Big Bang theory?

It is a consequence of gauge symmetry. If such symmetry was broken in the early universe, then big bang nucleosynthesis still suggests strict bounds on the amount of possible charge nonconservation.

 

[cadnr]

But quarks and leptons formed at different times. Or is that not important?

 

[Chronos]

Here is a related idea:
http://aps.arxiv.org/abs/astro-ph/0409421

 

[yuiop]

I am curious. If the universe created an excess of normal matter over anti matter could it be possible that it created an excess of electrons over protons? If excess electrons were gravitationally attracted to galaxies and formed a halo which can not collapse completely because of electrostatic repulsion, woud the effect be the same as having dark matter in galaxies? Would such a cloud of electrons be detectable by the scattering or whatever that it has on light coming from distant stars and galaxies? Just an idle thought. I haven't really worked it out ;)