Length Contraction of Electrons

In summary, electrons are point particles with no length to contract. To an outside observer, the length between electrons would contract due to special relativity. This would increase their mutual repulsion, but the repulsive force would still be the same. The electron drift velocity in a wire is on the order of millimeters per second, and the relativistic length contraction of the distance between electrons can explain the appearance of magnetic effects.
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If you have a still wire with electrons moving through it, to an outside observer at rest relative to the wire, would the space between the electrons contract? I would think that special relativity causes the electrons to contract, (not the space between them) but the contracting of the electrons would cause the electrons to come closer together.
 
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  • #2
Electrons are point particles whose length is zero, so there's nothing to contract. The way to get the electrons to move closer together is for you, the observer, to be in motion relative to the wire; that will contract the length between them.
 
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  • #3
Nugatory said:
Electrons are point particles whose length is zero, so there's nothing to contract.
They have electric fields, which are contracted when the electron moves.
Nugatory said:
The way to get the electrons to move closer together is for you, the observer, to be in motion relative to the wire; that will contract the length between them.
Which would increase their mutual repulsion, if the electrons (their E-fields) weren't contracted as well.
 
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  • #4
Exactly, and if the repulsions between the electrons contract, wouldn't that allow them to become closer together?
 
  • #5
Electron drift velocity (q.v.) in wire is on the order of millimeters per second.
 
  • #6
Scheuerf said:
Exactly, and if the repulsions between the electrons contract, wouldn't that allow them to become closer together?
It allows them to be closer together in the observers frame than in the electrons frame, while the repulsive force is the same.

Scheuerf said:
the contracting of the electrons would cause the electrons to come closer together.
That's a
misleading way to put it. Contracted repulsive fields are still repulsive, and don't bring anything together.
 
  • #7
Doug Huffman said:
Electron drift velocity (q.v.) in wire is on the order of millimeters per second.

That is true, which makes it all the more remarkable that the effects of the tiny relativistic length contraction of the distance between them is sufficient to explain the appearance of magnetic effects. See, for example, http://physics.weber.edu/schroeder/mrr/MRRhandout.pdf
 

FAQ: Length Contraction of Electrons

What is length contraction of electrons?

Length contraction of electrons is a phenomenon in the field of physics where the length of an electron appears shorter when it is moving at high speeds. This is due to the effects of special relativity, which states that as an object approaches the speed of light, its length appears to decrease from the perspective of an observer.

How does length contraction of electrons occur?

Length contraction of electrons occurs because of the time dilation effect of special relativity. As an electron moves at high speeds, its time frame is slowed down, causing its length to appear shorter to an observer. This is because the distance between two points is measured by the time it takes for light to travel between them, and as time slows down for the electron, the distance appears shorter to the observer.

Does length contraction only occur for electrons?

No, length contraction can occur for any object that is moving at high speeds. However, it is most noticeable for particles with extremely small masses, such as electrons.

How does length contraction affect the properties of electrons?

Length contraction does not affect the properties of electrons, as it is simply a result of the effects of special relativity. The mass and charge of an electron remain constant regardless of its speed or length contraction.

Can length contraction of electrons be observed in everyday life?

No, length contraction of electrons can only be observed in experiments involving extremely high speeds, close to the speed of light. In everyday life, the speeds of electrons are not high enough for length contraction to be noticeable.

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