How does Earth maintain its electric charge balance?

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Discussion Overview

The discussion revolves around how Earth maintains its electric charge balance, exploring concepts related to charge distribution, current flow, and the implications of charging objects through induction. Participants examine the nature of Earth's charge, the behavior of electric currents, and the analogy of capacitors in this context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant claims that Earth has a charge of -1.6×10^-19C or about 7 moles of excess electrons, which is countered by a deficiency in the upper atmosphere.
  • Another participant disputes the idea of Earth being an infinite source and sink of current, suggesting that current flows in and out, with charge transfer being a trivial exception.
  • There is a discussion about the concept of a closed circuit and how charge redistribution occurs when a negatively charged rod is brought near an uncharged metal ball.
  • Some participants propose that the charged ball acts as one plate of a capacitor, with Earth as the other plate, raising questions about the nature of the circuit when the ball is connected to ground.
  • Clarifications are made regarding the charge of an electron and the total charge of Earth, with corrections to earlier claims about the number of excess electrons.
  • Concerns are raised about whether Earth retains a charge after a charged object is removed, and whether this affects the overall charge balance.
  • There is a debate about the role of wires in circuits and how they relate to the concept of capacitors.

Areas of Agreement / Disagreement

Participants express differing views on the nature of Earth's charge balance, the behavior of electric currents, and the analogy of capacitors. No consensus is reached on these topics, and multiple competing perspectives remain throughout the discussion.

Contextual Notes

Participants highlight limitations in understanding charge conservation, the implications of connecting and disconnecting wires, and the definitions of current flow and charge transfer. These aspects remain unresolved.

Who May Find This Useful

Individuals interested in electric charge dynamics, circuit theory, and the conceptual understanding of capacitors may find this discussion relevant.

khushi
Earth has a charge of -1.6×10^-19C or about 7 moles of excess electrons on it's surface. This is compensated by an equal deficiency of electrons in the Earth's upper atmosphere.
Earth is also an infinite source and sink of current.
Now, when current flows into it, that means it loses electrons. So, to create balance, the upper atmosphere should also gain the same amount of electrons. How does that happen?
 
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khushi said:
Earth is also an infinite source and sink of current.
It is not.
Current that flows into it flows out again to an extremely good approximation. The only exception is a charge transfer between the atmosphere and the earth, where the answer to your question is trivial.
 
Oh okay yes, it has to flow out or else there won't be a closed circuit for current to flow. And i suppose it should be the same network, a part of which is touching the ground. Am I right? But when charging a metal ball by induction in which :-
An uncharged metal ball is supported on an insulating stand. A negatively charged rod is brought near it, causing charges to redistribute, with electrons pushed on the opposite side. So, if we connect a metal wire b/w the -ve end and gnd, the -ve charge flows into earth. So, we then remove the rod and the ball is +vely charged.
Now, where is the circuit in this?
 
khushi said:
And i suppose it should be the same network, a part of which is touching the ground.
With a single connection, you don't get relevant currents towards ground. You can make a small charge separation by putting some charge on a metal ball, yes. The sum of all charges of your lab experiment plus Earth will stay constant as charge is conserved.
 
But then the Earth would get a charge. And we can then remove the charged ball from the lab and the Earth will still have an extra charge. What about that?
 
Last edited by a moderator:
If you shoot the charged ball to space, yes, you change the charge of Earth by a tiny amount.
 
khushi said:
Now, where is the circuit in this?
The charged ball is one "plate" of a capacitor. The other plate is ground. The current is the standard displacement current found in any capacitor.
 
-1.6×10^-19C is the charge of one electron, not 7 moles.
 
Khashishi said:
-1.6×10^-19C is the charge of one electron, not 7 moles.
Sorry, it's a mistake, total charge is -6.8×10^5 C, which corresponds to 7 mole of excess electrons.
 
  • #10
DaleSpam said:
The charged ball is one "plate" of a capacitor. The other plate is ground. The current is the standard displacement current found in any capacitor.
But how can it be a capacitor when the ball and Earth are connected with a wire? When we remove the wire, then it can be seen as a capacitor but the charge traveled to Earth during the time wire was connected.
 
Last edited by a moderator:
  • #11
Huh? Capacitors are usually connected by wires in circuits. That doesn't change anything. The connecting and disconnecting would be a switch, separate from the capacitor.
 

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