What is the shape of an electron?

In summary, the study tries to probe, if any, the electric dipole moment of an electron. They didn't find any and can impose the upper limit of such dipole moment based on the resolution/accuracy of the experiment. It means that the QFT/QED model of an electron having no size (point particle) is valid, because the study could not find any kind of structure.
  • #1
phoenixankit
8
0
What does an electron look like? What is it made of? It has to be made of something? Can we/Have we been actually able see an electron?
 
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  • #2
phoenixankit said:
What is it made of? It has to be made of something?
Says who?
 
  • #3
Well, then how does it have mass?
 
  • #4
phoenixankit said:
Well, then how does it have mass?
It just does! :smile: (I don't get your point. If an electron were made of something else--call them thingons--how would that answer your question? Someone would just ask: What are thingons made of? They must be made of something!)

Current theory (the standard model of particle physics) holds that electrons are fundamental particles.
 
  • #5
Well, yeah, it is a lame Question...but the "it just does" part is what i did not expect from physics
If e's are just made of charges,charges are energy, and energy does not have mass
 
  • #6
Electrons are not made of charges. Charges are not energy. And things with energy behave as though they have mass.

From the particle point of view, the electron is a fundamental (pointlike) particle. If you prefer to think of things as their (quantum) fields, then individual electron have indeed been seen.
 
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  • #7
phoenixankit said:
Well, yeah, it is a lame Question...but the "it just does" part is what i did not expect from physics
Sure, saying "it just is" isn't much of an answer, but that might be the best we can do right now. I don't think there's an accepted answer explaining how mass exists.
If e's are just made of charges,charges are energy, and energy does not have mass
Sorry, but I don't understand any of these three statements. Electrons have charge, but I wouldn't say they are made of charges (whatever that might mean). Thus I don't know what "charges are energy" means, or why that would imply something about the electron's mass.
 
  • #8
Doc Al said:
Sure, saying "it just is" isn't much of an answer, but that might be the best we can do right now. I don't think there's an accepted answer explaining how mass exists.

Sorry, but I don't understand any of these three statements. Electrons have charge, but I wouldn't say they are made of charges (whatever that might mean). Thus I don't know what "charges are energy" means, or why that would imply something about the electron's mass.

My understanding of particle physics/QFT is pretty nil, so don't quote me on this, but I think the existence of mass is related to the Higgs Boson.
 
  • #9
You're right--my earlier statement is full of crap. The standard model does "explain" mass in terms of various couplings.
 
  • #10
Well, anyways, if you found my question to be stupid, forgive me, I'm just 14...
 
  • #11
size is unmeasurable, however the mass is known
 
  • #12
All so confusing...It has a mass, but it is just a point. Point particle. zero-dimensional. No volume.
Still got mass.

Anyways, thanks for the help...
 
  • #13
Its size is unmeasurable it may just be really really small or it might be as you said zero-dimensional
 
  • #14
phoenixankit said:
Well, then how does it have mass?

from the standard model, it achive its mass from the higgs field.

And what if the electron was made up of something (lets call it fnyquids), then we would as "what is the fnyquids made of?" And state "they have to be made up of something".. for all eternity, It just does not work as that, something has to be elemtary. And according to the leading theories and experimental data, the electron is an elementary particle.

And yes, the concept of point particles is perhaps a bit confusing in the beginning and hard to swallow, but the contradiction only comes from our classical way to look at nature. We have to allow us to leave our macroscopical world and enter the micrscopical world and play the game with its rules, not by our classical physics rules. See for example in the philosophy sub-forum where we had a loooong discussion about point particles etc.
 
  • #15
Have you heard of bootstrapping? It escaped the question of the most elementary particle by concentrating on the property that they are interchangeable. But I don't know much~
 
  • #17
profmo said:

Er.. no it doesn't.

The study tries to probe, if any, the electric dipole moment of an electron. They didn't find any and can impose the upper limit of such dipole moment based on the resolution/accuracy of the experiment. It means that the QFT/QED model of an electron having no size (point particle) is valid, because the study could not find any kind of structure.

http://physicsworld.com/cws/article/news/46085

Read the paper in this week's Nature.

This is also a very old thread to resurrect just to make an inaccurate statement.

Zz.
 
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  • #18
malawi_glenn said:
something has to be elemtary.

Actually, this statement is just as flawed as the one you are refuting. There is no such rule specifying it either way.
 
  • #19
are atoms spheres? protons?
 
  • #20
Electrons are very spherical

Folks,

I came across this article which has confused me

http://www.sciencedaily.com/releases/2011/05/110525131707.htm

I thought that electrons and photons cannot be described classically as spheres because they are smeared out in space until the act of measurement. Then because of the probabalistic nature of QM, we can only guess what it might look like...but they seemed to have measured it extremely accurately...it not making sense for me...

Thanks
 
  • #22
kthayes said:
are atoms spheres? protons?

Protons are composed of subatomic particles called quarks, so I would expect them to not be perfectly sphereical, but I really don't know.

As for atoms, they are definitely not spheres. Not usually at least. The combination of different electrons in their orbitals, which can change as the electrons get excited and jump around into other orbitals will have a noticeably different shape for each orbital. So the combination of all these orbitals doesn't tend to be perfectly spherical. At least I don't think so.
 
  • #23


bugatti79 said:
Folks,

I came across this article which has confused me

http://www.sciencedaily.com/releases/2011/05/110525131707.htm

I thought that electrons and photons cannot be described classically as spheres because they are smeared out in space until the act of measurement. Then because of the probabalistic nature of QM, we can only guess what it might look like...but they seemed to have measured it extremely accurately...it not making sense for me...

Thanks

Your thread was merged to this one. Please scroll back a bit to see the responses already given to this question.

Zz.
 
  • #24
Electron has shape?

Just read an article in the BBC:

http://www.bbc.co.uk/news/science-environment-13545453

Claiming that a group has managed to accurately measure the shape of a single electron.

Is this simply bad BBC science reporting? (as usual) Because from what I understand, electrons are found to be point-like particles at all testable energy scales, and 'points' don't have shape.
 
  • #25
Again, more newly-created threads have been merged into this one. Please scroll back up to earlier posts to see what has been written.

Zz.
 
  • #26


JesseC said:
Is this simply bad BBC science reporting?

Yes. A better statement would be that the electron's electric field has been confirmed to be spherically symmetric, with greater precision than before. A point particle produces a spherically symmetric electric field. Of course, so can a spherically symmetric charge distribution; but no sign of a finite size has been seen either. There are other experiments which set an upper limit on the radius of the electron's charge distribution.
 
  • #27
I see...so its bad reporting. So all those newbies out there like me reading that will be wrongly informed.
So my understanding is that you can't actually measure the shape of an electron because it has no shape but can measures its elecric field to within probabilities?

Cheers
 
  • #28
We detect and study electrons by way of their electromagnetic interactions (except for a very few experiments that involve the weak interaction), so any conclusions about the electron's shape or size come from the measured properties of its electric field (taken either in a classical or a quantum sense).
 
  • #29


jtbell said:
Yes. A better statement would be that the electron's electric field has been confirmed to be spherically symmetric, with greater precision than before. A point particle produces a spherically symmetric electric field. Of course, so can a spherically symmetric charge distribution; but no sign of a finite size has been seen either. There are other experiments which set an upper limit on the radius of the electron's charge distribution.

Actually, a spherically symmetry charge distribution should show a distortion, or wobble, in such a field. At high enough field, there will be a redistribution of the charge, which will then cause the presence of an electric dipole, which is what they were trying to detect. That is why this was done at such high fields in the first place. I'm sure future experiments will test this at even higher fields, if possible.

So the non-detection here puts an upper limit on the size, spherically symmetric or not. The experiment is still consistent with the QED picture of point particles.

Zz.
 
  • #30
phoenixankit said:
All so confusing...It has a mass, but it is just a point. Point particle. zero-dimensional. No volume.
Still got mass..

No. It is point-like, but this is not the same as being just a point. Electrons have extension. See the entry ''Are electrons pointlike/structureless?'' in Chapter B2 of my theoretical physics FAQ at http://arnold-neumaier.at/physfaq/physics-faq.html#pointlike

The modern explanation from quantum field theory is that a field is sonething whose intensity (or other properties) you can measure (in principle, not necessarily by an actual experiment) at every point in space. The fields have these properties without being composed of them; composition makes only sense if you can identify the parts.

A particle is a state of a quantum field in which, in some reference frame, all intensity is concentrated in a very small region. It is for a quantum field what a water droplet is for the macroscopic field asssociated with water.
 
  • #31
Research has just been released that shows that the electron is very spherical indeed! :D

I think ZapperZ, you can have no argument after this! :D

http://fxn.ws/jHwfeQ
 
  • #32
The Dude 321 said:
Research has just been released that shows that the electron is very spherical indeed! :D

I think ZapperZ, you can have no argument after this! :D

http://fxn.ws/jHwfeQ

Rather than reading 2nd hand report, why don't you read the ACTUAL paper?

The FIELD being detected shows no deviation from a spherical field. This means that in a high electric field, there were no charge redistribution on an electron, i.e. no presence of an electric dipole. This shows that we have no detected any "volume" to the electron.

Just because something is a "sphere" doesn't mean that it is also a point. An atom with an s-orbital electron is spherical. But put that atom in a strong-enough electric field, and you get distortion out of that spherical charge distribution. Why? Because there is a non-zero volume, and the charge can redistribute in response to the external field! This experiment is testing something even more stringent.

Zz.
 
  • #33
phoenixankit said:
Well, yeah, it is a lame Question...but the "it just does" part is what i did not expect from physics
If e's are just made of charges,charges are energy, and energy does not have mass

According to Maxwell theory charges are something like the opposite of energy. They are a discontinuity of polarization - in other words a place where energy can't move freely in response to stress. Energy might be especially concentrated around the discontinuity though.

In the model of the electron which corresponds to the Dirac equation, the charge moves around a small region somewhat randomly at the speed of light. But if you want to break down what an electron consists of, it's surely not just the charge but the effects of the charge and its motion in the region immediately surrounding the charge. It also appears to be the case that a free electron has a different configuration than a bound electron in an orbital of an atom.

Associated with the Standard Model is an unproven extension where most particles that had previously been thought of as elementary, including electrons, may consist of sub-quarks or preons. There is some experimental evidence indicating this possibility.
 
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  • #34
Electron is spherical: Nature

hi Guys,

I just caught wind of this updated result at Nature:

http://www.nature.com/nature/journal/v473/n7348/full/nature10104.html

Seems to me that what's being measured is an attribute of the electron that, classically, we would attribute to a spherical mass. Do you think they're claiming the electron is a sphere? I can't imagine they are.

Cheers,

Kevin
 
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  • #35


homology said:
hi Guys,

I just caught wind of this updated result at Nature:

http://www.nature.com/nature/journal/v473/n7348/full/nature10104.html

Seems to me that what's being measured is an attribute of the electron that, classically, we would attribute to a spherical mass. Do you think they're claiming the electron is a sphere? I can't imagine they are.

Cheers,

Kevin

nice to read

..."indicates that the electron is spherical at this improved level of precision"...



.
 
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