Thunderbolts of the Gods

[robinson]

If you mean the planet as a whole, no, not significantly.

I guess the word significantly means something different to you.

The solid Earth has a negative charge of about a half million coulombs. The atmosphere has a roughly equal and opposite charge, so that the Earth as a whole is roughly neutral. The charge difference produces a "fair weather electric field" in the lower atmosphere averaging about 6 volts per meter -- however, this field varies strongly with altitude, and is nearly 100 volts per meter at ground level. The total voltage difference between the ground charge and the atmosphere's charge (which exists roughly 30-50 km up) is about 300,000 volts. A simple calculation shows that the total energy stored in the fair weather electric field is 150 billion joules.

Since air isn't a perfect insulator, electrons leak from ground to air constantly, trying to reduce the charge difference to zero. This current amounts to 2000 amps. Another simple calculation shows that the electrical power dissipated is 600 megawatts. This is the output of a large electrical power plant. While it's theoretically possible to harness this power for use by people, the fact that it's spread throughout the entire globe (to the tune of about a watt per square kilometer) makes it impossible in practice.

http://www.madsci.org/posts/archives/2000-10/972662284.Es.r.html

The surface and lower atmosphere has a charge, especially during thunderstorms, and the upper atmosphere has the opposite charge. Lightning discharges (part of) that difference. It's not much different from rubbing a balloon on a carpet and getting a little spark.

Since charge is constantly leaking between ground and air, there must be an "electrical generator" somewhere which is pumping electrons from air to ground, against the electric field. Thunderstorms are the generators. The movement of air and charged cloud particles within them separates electrical charges vertically; lightning then transfers the extra electrons at the base of the cloud to the ground. Positive charge at the top of the cloud leaks into the upper atmosphere. This recharges the fair weather electric field.

http://www.madsci.org/posts/archives/2000-10/972662284.Es.r.html

I'm not sure if that explanation is correct either. Lightning is one of the least understood natural phenoms still. Some sources, like the one I quoted, think thunderstorms are the source of the charge. Others differ. Some even think negative and positive charges somehow flow apart inside the cloud. It is strange.

 

[robinson]

Isn't the Earth charged? In which case, what maintains it, and why does it not get neutralised by the hundreds of thunderbolts striking the ground every minute? Or does lightning maintain Earth's charge, in which case, what stops it increasing indefinitely?

Those are good questions. There are lots of theories, but ongoing investigations keep bringing up new stuff, and there is certainly no consensus on the matter. There are 6,000 lightning bolts every second. There has to be a source for the amount of energy flowing. Some think it is water molecules rubbing against each other.

 

[sol invictus]

I guess the word significantly means something different to you.

Umm, no, it doesn't. The problem here seems to be your reading comprehension abilities. The planet does not have a significant net charge. The surface does, but the atmosphere compensates.

I'm not sure if that explanation is correct either. Lightning is one of the least understood natural phenoms still. Some sources, like the one I quoted, think thunderstorms are the source of the charge. Others differ. Some even think negative and positive charges somehow flow apart inside the cloud. It is strange.

There cannot be a "source" for charge - charge is conserved. What happens is there is a mechanism which separates positive and negative charges, creating a situation in which lightning will arc through the air and discharge the imbalance. Much like rubbing a balloon on a carpet.

No one disagrees about that.

The only debate I know of is over which mechanism for charge separation is most important. And by the way, yes that certainly does happen within clouds themselves - haven't you ever seen horizontal lightning?

 

[robinson]

The planet does not have a significant net charge. The surface does, but the atmosphere compensates.

The solid Earth has a negative charge of about a half million coulombs. The atmosphere has a roughly equal and opposite charge, so that the Earth as a whole is roughly neutral. The charge difference produces a "fair weather electric field" in the lower atmosphere averaging about 6 volts per meter -- however, this field varies strongly with altitude, and is nearly 100 volts per meter at ground level. The total voltage difference between the ground charge and the atmosphere's charge (which exists roughly 30-50 km up) is about 300,000 volts. A simple calculation shows that the total energy stored in the fair weather electric field is 150 billion joules.

Another tough choice. Believe you, or experts and published authors who disagree with you. Hmm... what to do, what to do ...

There cannot be a "source" for charge - charge is conserved.

Same problem, really smart people talk about the source of a charge, while you claim there is no such thing.

What happens is there is a mechanism which separates positive and negative charges, creating a situation in which lightning will arc through the air and discharge the imbalance. Much like rubbing a balloon on a carpet.

What is the source of the charge on the balloon? Or is there no charge, because the carpet and the balloon, viewed together, still have the same charge? I'm not sure if it your strange use of words, or something else that makes it confusing. First you say there is no "significant net charge", then you say the charges are seperate, leading to lightning. I'm sure you will explain.

The only debate I know of is over which mechanism for charge separation is most important.

Indeed. Is it friction? Gravity? Heat? Updrafts? State change? Ice? Dust? The mysteries of lightning are vast. As are the energies of the earth and sky.

 

[Ziggurat]

Another tough choice. Believe you, or experts and published authors who disagree with you. Hmm... what to do, what to do ...

Are you honestly that clueless? Look at your own source:

The solid Earth has a negative charge of about a half million coulombs. The atmosphere has a roughly equal and opposite charge, so that the Earth as a whole is roughly neutral.

Your "expert" isn't saying anything different from what Sol said. Jeeze.

What is the source of the charge on the balloon?

The carpet, which gives up electrons which attach to the balloon

Or is there no charge, because the carpet and the balloon, viewed together, still have the same charge?

Well, yes: there's no net charge on the balloon-carpet system, only a charge separation. Likewise there's no significant net charge on the earth, only a charge separation between the solid earth and the atmosphere, which is also part of the earth.

I'm not sure if it your strange use of words, or something else that makes it confusing.

It's not Sol, it's you. The answers were staring you in the face. Your own source said exactly the same thing as Sol said.

 

[sol invictus]

What is the source of the charge on the balloon? Or is there no charge, because the carpet and the balloon, viewed together, still have the same charge? I'm not sure if it your strange use of words, or something else that makes it confusing. First you say there is no "significant net charge", then you say the charges are seperate, leading to lightning. I'm sure you will explain.

Zig answered rather thoroughly. Maybe you need to look up the meaning of the term "net" as in "net charge"?

You like immutable and absolute laws of physics, right? Well if there are any, conservation of electric charge is one of them. The total (or net) charge in some region can only change if some current flows into or out of it. When you rub the balloon on the carpet, electrons go onto one (Zig says onto the balloon - could be), leaving behind positively charged ions in the carpet. The total (or net) charge hasn't changed - it's still zero, or close - but the balloon has a negative charge and the carpet has a positive charge. That creates an electric field between them, which means there's a force pulling the electrons and ions towards each other (which is why the balloon will stick to the carpet). If the field gets strong enough, it can ionize the air temporarily (ooh... plasma!) and allow the excess electrons to arc back to the carpet, making a visible spark and possibly giving you a shock. That's a small version of a lightning bolt.

Not very mysterious, is it?

 

[iantresman]

Umm, no, it doesn't. The problem here seems to be your reading comprehension abilities. The planet does not have a significant net charge. The surface does, but the atmosphere compensates.

.
The magnitude of the charge is irrelevant. The Earth has a measurable "fair weather field" of about 100V/m resulting in a potential difference of about 400,000V between the Earth and the ionosphere, resulting in a measurable charge.(Ref) I think its study is called "atmospheric electrostatics"

So I think the questions still stands, what maintains or relieves the Earth's charge? And then how might the magnitude of that charge change if it was applied the Sun's very different environment?

I am well aware of "proofs" that the sun can not hold a charge, but I am also aware of papers that argue otherwise. See for example:

• Existence of Net Electric Charges on Stars, Oster, Ludwig; Philip, Kenelm W., Nature, Volume 189, Issue 4758, pp. 43 (1961)
• New evidence that the Sun carries a large net negative electric charge, Bailey, V. A., Planetary and Space Science, Volume 11, Issue 12, p. 1501-1502 (1963)
• On the electric charge of stars., Shvartsman, V. F., in Zh. Ehksp. Teor. Fiz., Tom 60, p. 881 - 884 (1971)
• An electrical charging process applicable to solar conditions, Crew, E. W., The Observatory, vol. 101, p. 13-19 (1981)
• The Effect of the Solar Electric Charge on the Solar Irradiance, Chen, F. S.; Jiang, S. Y.; Chen, Y., Proceedings of the 21st Century Chinese Astronomy Conference, held August 1-4, 1996.
• Electrically charged compact stars and formation of charged black holes, Ray, Subharthi et al, Physical Review D, vol. 68, Issue 8, id. 084004, arXiv:astro-ph/0307262 (2003). See also 2006 paper.
• The electric field and charge in the solar corona, Yefimenko, V. M.; Tokii, V. V.; Tokii, N. V., Kinematika i Fizika Nebesnykh Tel, vol. 20, no. 1, p. 27-33, 02/2004

I note that these papers cover 5 decades, and most (but no all) are peer reviewed.

 

[Ziggurat]

The magnitude of the charge is irrelevant. The Earth has a measurable "fair weather field" of about 100V/m resulting in a potential difference of about 400,000V between the Earth and the ionosphere, resulting in a measurable charge.

Fields don't create charges (though they can move them). They are created by charges, and the fields they create push charges towards neutrality, not towards charge segregation. And in the case of the large electric field in the earth's atmosphere, it's due to charge separation, NOT due to a net charge on the earth. Which was Sol's point, and which you evidently cannot grasp.

So I think the questions still stands, what maintains or relieves the Earth's charge?

What charge? A net charge? No evidence that it's significant. A local charge (ie, charge separation)? Sol already acknowleged that.

And then how might the magnitude of that charge change if it was applied the Sun's very different environment?

Well, it wouldn't produce a net charge. And it's bloody unlikely to produce much charge segregation either. You see, air is a fairly good insulator. It can sustain large electric fields without significant current flow. But plasma is not a good insulator - quite the reverse. Try to separate charges inside a plasma, and they have a very strong tendency to flow back to each other. So we should not expect anything similar to happen on the sun.

I am well aware of "proofs" that the sun can not hold a charge,

Really? Funny, I've never heard such an argument. I've heard arguments which place limits on the charge of the sun, but that's not the same thing.

but I am also aware of papers that argue otherwise. See for example:

• Existence of Net Electric Charges on Stars, Oster, Ludwig; Philip, Kenelm W., Nature, Volume 189, Issue 4758, pp. 43 (1961)

• 
  
  Oh, that's just too funny. You didn't even read the abstract, did you?
  "V. A. BAILEY1 has urged that a variety of geophysical and astrophysical phenomena can be explained by a net charge on the Sun of -1.5 times 1028 e.s.u., admitting that this proposal is at variance with some of the "most cherished notions"2 of theoretical astrophysicists. Attention may therefore be directed to certain deductions from Bailey's hypothesis that are in conflict with unambiguous evidence from observation as well as with what is generally regarded as sound theory."
  In other words, this paper is blowing Bailey's hypothesis of a large charge on the sun out of the water.
  
  

  [*]An electrical charging process applicable to solar conditions, Crew, E. W., The Observatory, vol. 101, p. 13-19 (1981)

  
  What this paper describes is actually just a charge separation process. It doesn't produce a net charge on the sun, and it's driven by radiation pressure (meaning it sucks up energy to create, it doesn't create any energy itself). And the maximum field they predict (~300 V/cm) is far below what causes lightning on earth (~30,000 V/cm).
  
  

  [*]Electrically charged compact stars and formation of charged black holes, Ray, Subharthi et al, Physical Review D, vol. 68, Issue 8, id. 084004, arXiv:astro-ph/0307262 (2003). See also 2006 paper.

  
  http://arxiv.org/PS_cache/nucl-th/pdf/0604/0604039v1.pdf
  From the conclusion:
  "In our study, we have shown that a high density system like a neutron star can hold huge charge of the order of 10²⁰ Coulomb considering the global balance of forces."
  Not exactly applicable to a sun like ours. Furthermore,
  "The stability of these charged stars are however ruled out from the consideration of forces acting on individual charged particles. They face enormous radial repulsive force and leave the star in a very short time... Finally, these charged stars are supposed to be very short lived, and are the intermediate state between a supernova collapse and charged black holes."
  
  

  I note that these papers cover 5 decades, and most (but no all) are peer reviewed.

  
  I'm sure you're real proud of having dug up a bunch of titles that seem relevant. But it helps to actually have some grasp of the contents of such papers. You evidently did not.

 

[Dancing David]

Yes it would if it was a standard circuit, but in the EU model of the sun gravity itself ionizes the star and maintains this voltage.

Now that is a new one, how does that work?

we have heard about the Birkeland currents but how does gravity ionise the sun?

 

[Dancing David]

Isn't the Earth charged? In which case, what maintains it, and why does it not get neutralised by the hundreds of thunderbolts striking the ground every minute? Or does lightning maintain Earth's charge, in which case, what stops it increasing indefinitely?

I beleive that lightning is a zero sum game.

Water falling captures electrons and creates a positive charge in the local atmosphere and a negative charge on the ground, the lightning strike balances it out again.

 

[Dancing David]

Do you have a source for that? What causes lightning is far from decided, according to my sources. It certainly isn't the same as rubbing a balloon.

Not that hard to find, water grap electrons, carries them to the ground, they build up as the positive charge build up in the air until boom....

What makes you think it is a mystery?

 

[iantresman]

Well, it wouldn't produce a net charge. And it's bloody unlikely to produce much charge segregation either. You see, air is a fairly good insulator. It can sustain large electric fields without significant current flow. But plasma is not a good insulator - quite the reverse. Try to separate charges inside a plasma, and they have a very strong tendency to flow back to each other. So we should not expect anything similar to happen on the sun.

.
Indeed, plasmas are very good conductors which tend to neutralize, hence quasi-neutrality. But they are also capable of producing charge separation regions, such as those in double layers, and also in charged particle beams.

Really? Funny, I've never heard such an argument. I've heard arguments which place limits on the charge of the sun, but that's not the same thing.

.
I was attempting to characterize some of the critics in this thread who claimed to have demonstrated that the sun can not possible hold any kind of charge.

Oh, that's just too funny. You didn't even read the abstract, did you?

.
Yes, I've read Bailey's paper, and note he also has a subsequent paper, but I posted the wrong abstract.

http://arxiv.org/PS_cache/nucl-th/pdf/0604/0604039v1.pdf
From the conclusion:
"In our study, we have shown that a high density system like a neutron star can hold huge charge of the order of 10²⁰ Coulomb considering the global balance of forces."
Not exactly applicable to a sun like ours. Furthermore,
"The stability of these charged stars are however ruled out from the consideration of forces acting on individual charged particles. They face enormous radial repulsive force and leave the star in a very short time... Finally, these charged stars are supposed to be very short lived, and are the intermediate state between a supernova collapse and charged black holes."

.
I believe there may be analogies.

I'm sure you're real proud of having dug up a bunch of titles that seem relevant. But it helps to actually have some grasp of the contents of such papers. You evidently did not.

.
Yes thank you. Hopefully the phenomena we see in some parts of the Universe may give us clues to what is happening in others.

I agree with that we are talking about charge separation regions, though depending on the region being studied, we may see a net charge.

 

[Ziggurat]

Indeed, plasmas are very good conductors which tend to neutralize, hence quasi-neutrality. But they are also capable of producing charge separation regions, such as those in double layers, and also in charged particle beams.

All of which require some outside driving force (such as thermal gradients) to create, and none of which are self-sustaining.

I was attempting to characterize some of the critics in this thread who claimed to have demonstrated that the sun can not possible hold any kind of charge.

Like who? Perhaps I missed it, but I don't recall anyone making such a claim.

I believe there may be analogies.

There is more than just an analogy, there's a direct equivalence: namely, that even for a neutron star (where gravity's nonlinearity becomes significant), gravity still cannot confine individual charge carriers if there is a large net charge, and so will quickly lose most of that charge. Which is exactly what I found when I went through the calculations based upon BAC's number for the voltage on the sun. The sun cannot hold a large net charge, because there is no available force which could keep it confined. Note I didn't say no net charge. But it's going to be quite small, on the order of 100 Coulombs for our sun. You're not going to get any energy of any note out of that small a charge.

 

[The Man]

The magnitude of the charge is irrelevant.

The magnitude of any charge is absolutely relevant.

The Earth has a measurable "fair weather field" of about 100V/m resulting in a potential difference of about 400,000V between the Earth and the ionosphere, resulting in a measurable charge.(Ref) I think its study is called "atmospheric electrostatics"

Again this refers to a charge separation between the surface of the Earth and the atmosphere. The Earth as a whole (atmosphere and all) has no significant net charge.

So I think the questions still stands, what maintains or relieves the Earth's charge? And then how might the magnitude of that charge change if it was applied the Sun's very different environment?

That answer is provided by your own (Ref)

Atmospheric electricity is like a massive photographic flash. An electrical charge is built up, a switch is closed, and electrons barge across a gas, ionizing it and producing light. But a flash is a complete circuit. In the case of the Earth, Ruhnke explained, the atmosphere completes the circuit.
Thunderstorm charge generation happens inside clouds. Current flows out of the tops of clouds - blue jets and red sprites may play a role - and connects with the upper atmosphere and the ionosphere. Ultimately, the current returns to Earth through the clear atmosphere. Because it's diffused over most of the globe, it's also quite weak at any given point.
"All three values are very difficult to measure," Ruhnke said. The current is 10-12 amps per square meter - "almost nothing." The field is about 100 volts per meter, meaning that the electric potential increases by about 200 volts from the ground to the top of Michael Jordan's head when he's standing still. Finally, air is an excellent insulator, so its conductivity is close to zero.

So the charge is not maintained but built up and then discharged.

I am well aware of "proofs" that the sun can not hold a charge, but I am also aware of papers that argue otherwise. See for example:

Existence of Net Electric Charges on Stars, Oster, Ludwig; Philip, Kenelm W., Nature, Volume 189, Issue 4758, pp. 43 (1961)

From the abstract of this paper, at least, it would seem that these authors are arguing against Bailey’s charged Sun.

V. A. BAILEY¹ has urged that a variety of geophysical and astrophysical phenomena can be explained by a net charge on the Sun of -1.5 × 10²⁸ e.s.u., admitting that this proposal is at variance with some of the ``most cherished notions''² of theoretical astrophysicists. Attention may therefore be directed to certain deductions from Bailey's hypothesis that are in conflict with unambiguous evidence from observation as well as with what is generally regarded as sound theory.

 

[The Man]

Yes it would if it was a standard circuit, but in the EU model of the sun gravity itself ionizes the star and maintains this voltage.

So the EU model of the Sun is based on gravity? Wouldn't that make it a GU (Gravitational Universe) model?

 

[Zeuzzz]

Could eveyone please stop saying that everything is neutral. Capacitance is a differential concept, you can claim that anything is neutral if you choose your own parameters. You could claim that a charged up anode is technically neutral if you include a mini atmosphere around that aswell to cancel out the charge. But that would be a pointless thing to do, and is with the Earth.

 

[Ziggurat]

Could eveyone please stop saying that everything is neutral.

Nobody said that.

Capacitance is a differential concept, you can claim that anything is neutral if you choose your own parameters.

No, actually, you can't. Gauss's law. Look it up. But you do need to be precise about what your system is. The "earth", in an astrophysics context, means both the ground and the surrounding atmosphere, usually considered out to about 100 kilometer elevation (the standard defined boundary with "space", IIRC).

You could claim that a charged up anode is technically neutral if you include a mini atmosphere around that aswell to cancel out the charge.

Only if that mini-atmosphere actually did cancel the charge. But if that were the case, then your anode would not create an electric field beyond that mini-atmosphere, which is not generally the case with anodes, is it? In most cases of interest, the anode does indeed have a net charge, even if you include a mini-atmosphere around it, and it's only by the inclusion of the anode that you get no net charge.

You really need a review of basic E&M.

 

[sol invictus]

Could eveyone please stop saying that everything is neutral. Capacitance is a differential concept, you can claim that anything is neutral if you choose your own parameters. You could claim that a charged up anode is technically neutral if you include a mini atmosphere around that aswell to cancel out the charge. But that would be a pointless thing to do, and is with the Earth.

You manifestly don't understand the meanings of the terms you're using. I suggest you pick up a high-school level physics textbook covering the basics of E&M.

 

[Zeuzzz]

You manifestly don't understand the meanings of the terms you're using. I suggest you pick up a high-school level physics textbook covering the basics of E&M.

Maybe you should stop with the Ad Hominem comments and outline what your actual problems are with what i said?

Capacitance is a differential concept, you can claim that anything is neutral if you choose your own parameters. You could claim that a charged up anode is technically neutral if you include a mini atmosphere around that aswell to cancel out the charge. But that would be a pointless thing to do, and is with the Earth.

I stand by that statement, it is largely correct. Capacitance is a differential concept. The capacitance of the Earth with respect to what? The moon? Pluto? All of the planets? The sun? Each area you choose will give a different value. Maybe it is you that does not understand the concept of capacitance.

 

[Ziggurat]

I stand by that statement, it is largely correct. Capacitance is a differential concept. The capacitance of the Earth with respect to what? The moon? Pluto? All of the planets? The sun? Each area you choose will give a different value. Maybe it is you that does not understand the concept of capacitance.

I'm quite sure he does. You, I'm not so sure of. Yes, you can consider capacitance with regard to an arbitrary reference, but doing so doesn't guarantee no net charge. The concept of net charge is not something you can define away via capacitance, as you suggested. I already detailed why. Look up Gauss's law. I'm serious about that. Because frankly, Sol's statement that you should look up an elementary physics textbook isn't an ad hominem: it's a rather honest evaluation of the skill level you're at. Because really, were you familiar with Gauss's law when you made the post he responded to? Do you see the problem? Do you understand the criticism I leveled against it in my previous post?