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chornedsnorkack
2012-Jan-14, 10:03 AM
What kinds of cosmological effects should be expected if the Universe had a modest but significant net electric charge? What kinds of observable effects?

(The results would be different for positive and negative Universe, because the masses of charge carriers differ.)

What are the observational upper bounds?

What I mean is NOT any speculations about difference between proton and electron charge - I mean exactly equal charges but small difference in count. I also do not mean any violation of charge conservation - I mean small initial charge exactly conserved ever since.

Also note that electric charge of universe is a different issue from baryon and lepton numbers. There is only one stable baryon, but several stable leptons, charged and neutral. While we have pretty good idea of the baryon number (protons and neutrons) and electron number (nearly equals proton number), we do not know lepton number, because we have little idea of the total number of low energy neutrinos, let alone any imbalance between neutrino and antineutrino number which may exist.

antoniseb
2012-Jan-14, 01:20 PM
If the net charge were to somehow remain spatially constant, it might not be a big deal, but immediately what springs to my mind is that (let's say there's a 1% excess of electrons) the Sun would then have a huge net negative charge which would create dipoles out of every solid object near it (including the planets), and then draw them in fairly rapidly.

WayneFrancis
2012-Jan-14, 01:31 PM
Would the electrons stay? Or would they be repelled out of the sun until it became overall neutral again? I would have though the charge imbalance would try to distribute itself evenly though out space.

chornedsnorkack
2012-Jan-14, 01:59 PM
Sun would not be neutral simply because electron mass differs from proton mass.

Since the gravitational potential energy of an electron on the surface of the Sun is about 2 eV, if there are excess electrons in world, Sun might achieve negative potential of 2 V, at which point free electrons would float and not fall in Sun (but neutral atoms and protons would be attracted).

But Sun can still be charged even in neutral world. After all, in hot corona, gases are ionized and electrons being far less massive than protons would travel at a far greater speed. Electrons might exceed Sunīs escape speed while protons fall back - this would go on until Sun becomes positively charged and electrostatically attracts electrons such that the net current becomes zero.

What is the observed electrostatical potential, relative to interstellar space, of Sun? Of Earth?

antoniseb
2012-Jan-14, 02:12 PM
Would the electrons stay? Or would they be repelled out of the sun until it became overall neutral again? I would have though the charge imbalance would try to distribute itself evenly though out space.

Hmmm. I was thinking that there would not be enough protons to keep it electrically neutral, but looking at it again, I think that the Sun could not have formed. With charge repulsion damping out rapidly gravitational differentiation, I don't think large clouds could gravitationally collapse enough to form stars.

neilzero
2012-Jan-14, 02:52 PM
Much of this may be unknowable, but a solar orbit space craft should be able to measure all but the smallest of differences in positive and negative in the solar wind 0.5 AU to 1.5 AU from the Sun, except for the neutrinos. Neil

chornedsnorkack
2012-Jan-14, 07:34 PM
but looking at it again, I think that the Sun could not have formed. With charge repulsion damping out rapidly gravitational differentiation, I don't think large clouds could gravitationally collapse enough to form stars.

Er, what if the charge repulsion is smaller than gravitational attraction, even for the average charge? If the net force is attraction, it remains attraction as the clouds collapse (both attraction and repulsion increase with inverse square).

Also, there is no reason why charge should stay average. Why cannot neutral particles segregate from the excess charge, and collapse?

antoniseb
2012-Jan-14, 08:16 PM
... Why cannot neutral particles segregate from the excess charge, and collapse?
OK, what do you have in the way of stable neutral particles that have enough mass that they don't travel near the speed of light, and interact enough that they can aggregate?

chornedsnorkack
2012-Jan-14, 08:24 PM
OK, what do you have in the way of stable neutral particles that have enough mass that they don't travel near the speed of light, and interact enough that they can aggregate?

While neutrons are unstable, electrons and protons readily combine into atoms.

antoniseb
2012-Jan-14, 09:07 PM
While neutrons are unstable, electrons and protons readily combine into atoms.
They don't stay that way when they are hot, they don't start that way since the reionization (which wouldn't have happened under these circumstances (I'm guessing)) and they'd have to do something special to collect enough to cool off.

trinitree88
2012-Jan-15, 04:58 PM
While neutrons are unstable, electrons and protons readily combine into atoms.

chornedsnorkack Neutrons are unstable when free, but are stable within most nuclei...(within the island of stability). When energy in the form of a high energy photon dissipates, it follows four paths:
1. It can scatter off a charged particle....Compton scattering. :
2. It can produce a photoelectron in the photoelectric effect. (Einstein's Nobel)
3. It can interact with the neutrino sea via the neutral current (the sea's universally interactive with all particles).
4. It can produce a particle/antiparticle pair. When the particle/antiparticle pair happens to be a charged pair, such as an electron positron pair, @ ~ 1.022 Mev/c2, there has always been seen a sum of zero charge. No particle detector, photographic emulsion, spark chamber, wire chamber, bubble chamber,... in trillions of events, has ever seen a charge excess of either type. The mystery that remains is how the putative Big Bang produced an enormous putative excess of protons over antiprotons, while producing in the same instant the identical putative excess of electrons over positrons, such that the two of them made lots of putative hydrogen, then helium, then other "metals in the early universe. For that effect, we have zero experimental confirmation or evidence. Like Jack Webb on Dragnet....."Just the facts, Maam,....just the facts." The fact is we as scientists have no solid idea where the universe came from. We have lots of putative theories with limited successes, and they remain our best hypotheses, but all of them carry the baggage of a lack of verifiable experimental results. So we keep working at it. Somebody will find a way to tie it all together coherently, but despite their sales, no coffee table book has ever done it yet. pete

P.S. An asymmetry in the production of mesons at the B-Factory does not explain the asymmetry in the production of protons over anti-protons (p/p-bar), nor does it explain the simultaneous asymmetry in leptons (electrons/positrons). please. pete

SEE:http://en.wikipedia.org/wiki/Compton_scattering
SEE:http://en.wikipedia.org/wiki/Photoelectric_effect
SEE:http://en.wikipedia.org/wiki/Neutral_current
SEE:http://en.wikipedia.org/wiki/Pair_production

trinitree88
2012-Jan-15, 05:10 PM
chornedsnorkack Neutrons are unstable when free, but are stable within most nuclei...(within the island of stability). When energy in the form of a high energy photon dissipates, it follows four paths:
1. It can scatter off a charged particle....Compton scattering. :
2. It can produce a photoelectron in the photoelectric effect. (Einstein's Nobel)
3. It can interact with the neutrino sea via the neutral current (the sea's universally interactive with all particles).
4. It can produce a particle/antiparticle pair. When the particle/antiparticle pair happens to be a charged pair, such as an electron positron pair, @ ~ 1.022 Mev/c2, there has always been seen a sum of zero charge. No particle detector, photographic emulsion, spark chamber, wire chamber, bubble chamber,... in trillions of events, has ever seen a charge excess of either type. The mystery that remains is how the putative Big Bang produced an enormous putative excess of protons over antiprotons, while producing in the same instant the identical putative excess of electrons over positrons, such that the two of them made lots of putative hydrogen, then helium, then other "metals in the early universe. For that effect, we have zero experimental confirmation or evidence. Like Jack Webb on Dragnet....."Just the facts, Maam,....just the facts." The fact is we as scientists have no solid idea where the universe came from. We have lots of putative theories with limited successes, and they remain our best hypotheses, but all of them carry the baggage of a lack of verifiable experimental results. So we keep working at it. Somebody will find a way to tie it all together coherently, but despite their sales, no coffee table book has ever done it yet. pete

P.S. An asymmetry in the production of mesons at the B-Factory does not explain the asymmetry in the production of protons over anti-protons (p/p-bar), nor does it explain the simultaneous asymmetry in leptons (electrons/positrons) to about ~ 80 orders of magnitude....there are ~1080 protons in the universe..... please. pete

SEE:http://en.wikipedia.org/wiki/Compton_scattering
SEE:http://en.wikipedia.org/wiki/Photoelectric_effect
SEE:http://en.wikipedia.org/wiki/Neutral_current
SEE:http://en.wikipedia.org/wiki/Pair_production
SEE:http://en.wikipedia.org/wiki/Island_of_stability

korjik
2012-Jan-15, 05:53 PM
Sun would not be neutral simply because electron mass differs from proton mass.

Since the gravitational potential energy of an electron on the surface of the Sun is about 2 eV, if there are excess electrons in world, Sun might achieve negative potential of 2 V, at which point free electrons would float and not fall in Sun (but neutral atoms and protons would be attracted).

But Sun can still be charged even in neutral world. After all, in hot corona, gases are ionized and electrons being far less massive than protons would travel at a far greater speed. Electrons might exceed Sunīs escape speed while protons fall back - this would go on until Sun becomes positively charged and electrostatically attracts electrons such that the net current becomes zero.

What is the observed electrostatical potential, relative to interstellar space, of Sun? Of Earth?

The Coulomb force is around 30 orders of magnitude stronger than gravity. As stellar energies, the electrons dont have enough energy or inertia to overcome that much force and get much in the way of charge separation. The large-scale electrostatic potential is basically zero.

chornedsnorkack
2012-Jan-15, 06:03 PM
The Coulomb force is around 30 orders of magnitude stronger than gravity.
For which charges?

As stellar energies, the electrons dont have enough energy or inertia to overcome that much force and get much in the way of charge separation. The large-scale electrostatic potential is basically zero.

You see a good reasoning why a large scale electrostatic potential of a few volts should be expected - but why not a few hundred volts?

Somehow, electrostatic potentials of millions of volts are generated between Earth and clouds, before they are discharged by lightning. But what is the electrostatic potential between, say, Earth and Moon?

korjik
2012-Jan-15, 09:34 PM
For which charges?


You see a good reasoning why a large scale electrostatic potential of a few volts should be expected - but why not a few hundred volts?

Somehow, electrostatic potentials of millions of volts are generated between Earth and clouds, before they are discharged by lightning. But what is the electrostatic potential between, say, Earth and Moon?

Dont put words in my mouth. I see a reason why there cant be a large scale electric potential of even a few volts. Even small potentials over the size of a solar system is an immense amount of energy that is just not there.

Atmospheric and interplanetary electric fields are very much completely different things. The atmospheric system is able to be because of atmospheric convection. This same convection prevents discharge by preventing the charges simply being able to travel ballistic paths back to one another. In the atmosphere, an ion is repeatedly scattered by other atmospheric molecules and cant travel to an oppositely charged ion. Which, by the way is another major difference. Atmo charges are carried by positive and negative ions, not protons and electrons. That makes for very major differences in dynamics. Interplanetary fields would be mostly protons and electrons, or ions and electrons. Either way, the electrons tiny mass makes the coulomb force able to drag the electrons to any nearby ions until quasi-neutrality is achieved. Also remember that a dense space plasma is good vacuum by atmosphere standards.

What do you mean 'For which charges?' a charge is a charge. A kilogram of electrons will feel more than 1030 times more electrostatic force than gravitational. Alot more, if my estimation is correct. Protons will also. Basically for any non-GR situation, if there is an electric force and a gravitational force, you can ignore the gravitational force cause it is so small. It is pretty basic plasma physics to figure out the amount of force due to charge separation and see what that means.

ngc3314
2012-Jan-16, 03:47 AM
The sort of standard discussion on this happened in the literature way back when, based on gravitational separation of charge carriers:

Bally and Harrison 1978 (http://adsabs.harvard.edu/abs/1978ApJ...220..743B):


It is shown that all gravitationally bound systems - stars, galaxies, and clusters of galaxies - are positively charged and have a charge-to-mass ratio of the order of 100 coulombs per solar mass. The freely expanding intergalactic medium has a compensating negative charge. The immediate physical consequences of an electrically polarized universe are found to be extremely small.


Barnes 1979 (http://adsabs.harvard.edu/abs/1979ApJ...229..679B):


The positive electric charge density associated with the internal electric fields of self-gravitating systems in hydrostatic equilibrium can be canceled by nearby external flowing plasmas, such as winds. For example, it can be shown that the positive electric charge of a star is likely to be completely screened by its stellar wind. Because winds and other nonstatic phenomena are widespread, the electrical polarization due to the positive charge on static systems such as stars should occur on relatively local scales, in contrast to the universal scale recently suggested by Bally and Harrison. The latter viewpoint would be correct only if the entire universe were in strict hydrostatic equilibrium.



The considerations were basic enough that the issue pretty much dropped from discussion.

chornedsnorkack
2012-Jan-16, 12:21 PM
Agreed that plasma is a relatively good conductor compared to dry air near Earth, and therefore the electrostatic fields should be weak.

Plasma is not superconducting, though, and for that reason the fields and potentials should not be exactly zero.

Say that an average proton in the crown of the Sun has an average speed of 750 km/s. Then it has average kinetic energy of approximately 3 keV.

As it escapes Sun, it is significantly slowed down by the gravity (to the 450 km/s speed of solar wind), losing about 2 keV of its initial 3 keV energy.

But if the electrons in the crown of the Sun have similar kinetic energy to the protons there due to equipartition (about 3 keV) then they are very much faster than protons (because lighter) at about 30 000 km/s. They should also not be significantly slowed by gravity (losing only about 1 eV in escape).

Thus they should run far ahead of the protons and give Sun a positive charge - until and unless they are slowed down by the positive charge of the Sun.

We should thus expect an electrostatic potential of the Sun in the region of 2 kV. Perhaps concentrated near the Sun as suggested.

The fields may weaken away from Sun. But notice that when a flow of plasma, like solar wind, encounters a magnetic field crossing the flow, such as Earth magnetosphere, electrostatic fields should be induced again - as Lorenz forces deflect protons one way and electrons the other way, electrostatic potential should be set up.

What is the order of magnitude of the electrostatic field induced by Earth magnetosphere?

iantresman
2012-Jan-24, 03:34 PM
What kinds of cosmological effects should be expected if the Universe had a modest but significant net electric charge? What kinds of observable effects?

In 1959, Herman Bondi (http://en.wikipedia.org/wiki/Hermann_Bondi) and R.A. Lyttleton (http://en.wikipedia.org/wiki/R.A._Lyttleton) proposed "The possibility of a general excess of charge in the universe (http://rspa.royalsocietypublishing.org/content/252/1270/313.short)" in Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 252, No. 1270 (Sep. 29, 1959), pp. 313-333. The abstract and full text are freely available online.

iantresman
2012-Jan-24, 03:44 PM
Say that an average proton in the crown of the Sun has an average speed of 750 km/s. Then it has average kinetic energy of approximately 3 keV.

As it escapes Sun, it is significantly slowed down by the gravity (to the 450 km/s speed of solar wind), losing about 2 keV of its initial 3 keV energy.

But if the electrons in the crown of the Sun have similar kinetic energy to the protons there due to equipartition (about 3 keV) then they are very much faster than protons (because lighter) at about 30 000 km/s. They should also not be significantly slowed by gravity (losing only about 1 eV in escape).

I believe that the Solar Wind accelerates from the Sun. See "Explaining the acceleration of the fast solar wind (http://www.obspm.fr/actual/nouvelle/jun05/solarw.en.shtml)" at Observatoire de Paris, in particular, Figure 2.

antoniseb
2012-Jan-24, 04:27 PM
I believe that the Solar Wind accelerates from the Sun. See "Explaining the acceleration of the fast solar wind (http://www.obspm.fr/actual/nouvelle/jun05/solarw.en.shtml)" at Observatoire de Paris, in particular, Figure 2.
I'm not sure what you are saying here. Are you saying that you believe that Solar Wind is accelerated in the corona, as opposed to a more broad definition of "from the Sun"? That seems to be a hypothesis of the page you linked.

iantresman
2012-Jan-24, 04:58 PM
I'm not sure what you are saying here. Are you saying that you believe that Solar Wind is accelerated in the corona, as opposed to a more broad definition of "from the Sun"? That seems to be a hypothesis of the page you linked.

Figure 2 that I mentioned, seems to show two models in which the Solar Wind velocity increases up to 1AU. I am yet to find a paper which presents measured data at various distances from the Sun.

chornedsnorkack
2012-Feb-03, 01:34 PM
Yes, but it speaks about the possibility of unequal proton and electron charge, and charge creation.

How about a simple count difference between protons and electrons?