# Conservation of charge in the Universe

• I
• Pushoam
In summary, a closed universe with only two electrons is impossible because it contradicts with Gauss theorem.
Pushoam
TL;DR Summary
Conservation of charge
The charge of an isolated system is conserved.
This implies the charge of the universe is constant.
This implies that charge can neither be created nor destroyed.
This implies that the net positive charge and the net negative charge of the universe are conserved. Is this right?

Pushoam said:
TL;DR Summary: Conservation of charge

This implies that the net positive charge and the net negative charge of the universe are conserved. Is this right?
A closed universe is neutral, i.e., total positive charges and total negative charges cancel by Gauss theorem. For an open universe which has infinite volume and where Gauss theorem is not applicable, I don't think we can say whether infinite number of charge particles have finite net conserved sum with zero, positive or negative sign.

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Pushoam and jbriggs444
anuttarasammyak said:
I don't think we can say whether infinite number of charge particles have finite net conserved sum with zero, positive or negative sign.
Indeed, this would be very much like evaluating the sum of an infinite, conditionally convergent series. The answer you get depends on the order in which you do the summation.

[It's not really conditionally convergent because it is not convergent at all]

So, for a close universe, the total charge, total positive charge and total negative charge are constant. Is it so?

anuttarasammyak said:
A closed universe is neutral...
It makes sense, but how do we know this? For all we know, the Universe started with a net charge!

-Dan

Delta2, Pushoam and topsquark
topsquark said:
anuttarasammyak said:
A closed universe is neutral.
It makes sense, but how do we know this? For all we know, the Universe started with a net charge!
In a closed universe let us take any closed surface. The universe is divided into two parts : inside the surface and outside the surface. Electric flux go through the surface. The flux correspond to all the charges inside the surface in one end and to all the charges outside the surface in other end. Thus we know that charges inside and outside cancel.
This is the explanation I find in section 111 of The Classical Theory of Fields by Landau and Lifshitz. How do you think of this discussion ?

PeroK and topsquark
anuttarasammyak said:
In a closed universe let us take any closed surface. The universe is divided into two parts : inside the surface and outside the surface. Electric flux go through the surface. The flux correspond to all the charges inside the surface in one end and to all the charges outside the surface in other end. Thus we know that charges inside and outside cancel.
This is the explanation I find in section 111 of The Classical Theory of Fields by Lev Landau and Lifshitz. How do you think of this discussion ?
Ah! I see the point now. Hmmm.... wouldn't that argument have to hold for gravity as well? I'll have to ponder that one.

-Dan

anuttarasammyak said:
In a closed universe let us take any closed surface. The universe is divided into two parts : inside the surface and outside the surface. Electric flux go through the surface. The flux correspond to all the charges inside the surface in one end and to all the charges outside the surface in other end. Thus we know that charges inside and outside cancel.
This is the explanation I find in section 111 of The Classical Theory of Fields by Landau and Lifshitz. How do you think of this discussion ?
I don't follow this argument at all.

Delta2 and Hornbein
I interpreted : The surface integral of electric field is common for inside region and outside region but with opposite sign due to opposite direction of surface inside/outside. Applying Gauss theorem charges outside and charges inside are same amount but with different sign. Thus they cancel in sum.

anuttarasammyak said:
I interpreted : The surface integral of electric field is common for inside region and outside region but with opposite sign due to opposite direction of surface inside/outside. Applying Gauss theorem charges outside and charges inside are same amount but with different sign. Thus they cancel in sum.
So, a closed universe with only two electrons is impossible because ...

kered rettop
PeroK said:
So, a closed universe with only two electrons is impossible because ...
… it contradicts with Gauss theorem.

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Landau is saying that if you have a source of field lines, you must necessarily have a sink.

I'm not going to argue with that, but I think this requires a static universe as well as a closed one. It probably requires a classical universe as well - no quantum effects like vacuum screening.

vanhees71 and PeroK
Landau is saying that if you have a source of field lines, you must necessarily have a sink.

I'm not going to argue with that, but I think this requires a static universe as well as a closed one. It probably requires a classical universe as well - no quantum effects like vacuum screening.
Or, even, that in a closed universe with only two electons milling around, then Gauss's law doesn't hold.

anuttarasammyak said:
… it contradicts with Gauss theorem.
Let's see a proof of Gauss's Law for a closed universe.

vanhees71
PeroK said:
No. There's pair production, for example:

https://en.wikipedia.org/wiki/Pair_production
Charge conservation is certainly a revered law. But what assumption is it based on? Physics keeps on formulating conservation laws and then finding cases where they are violated. How do we know that at some silly energy level, pair production doesn't create, say, two positrons?

Edited: I originally wrote "creates".

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PeroK
kered rettop said:
Charge conservation is certainly a revered law. But what assumption is it based on? Physics keeps on formulating conservation laws and then finding cases where they are violated. How do we know that at some silly energy level, pair production doesn't create, say, two positrons?

Edited: I originally wrote "creates".
It would be odd and illogical to have a standard model and quantum theory where charge is not conserved when there is no evidence for it. Moreover, what would be the nature of the new law that encompases violation of charge conservation? Such a law can't properly be formulated until there is some idea of when it happens.

It's a common theme amongst science skeptics (and I'm not implying you are in this category), that physicists believe the current laws as though they were gospel. When, in fact, they are simply the laws that have hitherto withstood experimental tests.

kered rettop said:
But what assumption is it based on?
It's based on observation. Because Science.

If you want to argue that "maybe someday we'll see it violated", that's the same argument that even though we've never seen a flying reindeer, maybe we just haven't looked hard enough. I can push a million reindeer off a roof to their deaths, but the ever-growing pile of venison does not mean #1000001 won't fly.

Logically true, but hard to take seriously.

As an aside, charge conservation implies a zero-mass photon and vice versa. We see that a photon has a very, very tiny mass, entirely consistent with zero. Can I prove some future discover won't be different? No. But again, it would be silly to think otherwise.

Sorry, Rudolph. Off the roof with you.

Bystander
It's based on observation. Because Science.

If you want to argue that "maybe someday we'll see it violated", that's the same argument that even though we've never seen a flying reindeer, maybe we just haven't looked hard enough. I can push a million reindeer off a roof to their deaths, but the ever-growing pile of venison does not mean #1000001 won't fly.

Logically true, but hard to take seriously.
[Examines contrived parallel, sees glaringly obvious flaw, decides to ignore entire thing.]

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PeroK said:
It would be odd and illogical to have a standard model and quantum theory where charge is not conserved when there is no evidence for it. Moreover, what would be the nature of the new law that encompases violation of charge conservation? Such a law can't properly be formulated until there is some idea of when it happens.

It's a common theme amongst science skeptics (and I'm not implying you are in this category), that physicists believe the current laws as though they were gospel. When, in fact, they are simply the laws that have hitherto withstood experimental tests.
In the region accessible to us. Which is why it is foolish to assume that they are universal.

Motore, PeroK and Delta2
kered rettop said:
In the region accessible to us. Which is why it is foolish to assume that they are universal.
Why is it necessarily a foolish assumption? Just take it as a working hypothesis, to be used until evidence to the contrary is forthcoming.

Vanadium 50, jbriggs444, Motore and 3 others
kered rettop said:
In the region accessible to us. Which is why it is foolish to assume that they are universal.
We assume they apply until we observe that they do not. This doesn't mean we have chiseled these laws into immutable stone that can never be changed, we just haven't observed anything that violates them and we have no theoretical reason to believe that they will be.

Vanadium 50, Motore, PeroK and 2 others
In the end physics is a pragmatic applied science. You do the simplest thing that works.

It's provisional, like just about everything else in science.

Since the original question has been explored well, I think its a good time to close this thread.

Thank you all for contributing here.

Jedi

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renormalize, Motore, kered rettop and 1 other person

## 1. How is charge conserved in the Universe?

Charge is conserved in the Universe through the principle that the total electric charge in a closed system remains constant over time. This means that charges can be transferred between objects, but the total amount of charge in the system will remain the same.

## 2. What evidence supports the conservation of charge?

One of the main pieces of evidence supporting the conservation of charge is the fact that no experiment has ever been able to create or destroy electric charge. In every interaction involving charges, the total charge before and after the interaction remains the same.

## 3. Can charge be created or destroyed?

According to the principle of conservation of charge, charge cannot be created or destroyed. It can only be transferred from one object to another. This means that the total amount of charge in the Universe remains constant.

## 4. How does the conservation of charge relate to other conservation laws?

The conservation of charge is closely related to other conservation laws, such as the conservation of energy and the conservation of momentum. These laws all stem from the fundamental principle that certain quantities in the Universe remain constant over time.

## 5. What are the implications of the conservation of charge for the future of the Universe?

The conservation of charge plays a crucial role in understanding the behavior of particles and fields in the Universe. It helps us predict how charges will interact and how systems will evolve over time. By studying the conservation of charge, scientists can gain insights into the fundamental laws governing the Universe.

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