# Radius of Proton and Neutron equal or not?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by DarkDAVE, Apr 12, 2002.

1. ### DarkDAVERegistered Member

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I was just wondering, is the radius of a proton and neutron EXACTLY equal? I know that the neutron is very slightly heavier than the proton, but are they exactly of equal radius?

8X10^-16 Meters is what www.physlink.com says the radius of both protons and neutrons are but i get the feeling that it is a rounded off figure.

most scientific read outs that are acurate look more something like 1.6726231*10^-27 kg

The above mentioned value is the mass of a proton

1.6749286X10^-27 kg is the mass value of the heavier neutron.

Can anyone tell me if the radius of neutrons and protons are in fact exactly identical?

David

3. ### (Q)Encephaloid MartiniValued Senior Member

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A neutron is basically a proton with an electron in close orbit.

They're not actually shaped like a ball in the classical sense. Both are made up of quarks that move around each other. So essentially, the radius is the orbit of the quarks.

5. ### DarkDAVERegistered Member

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This electron in close orbit with the neutron, is it a meson? If so which nuclear force does it belong to? Weak or strong?

I was under the impression that mesons ocilate between protons, making each one a neutron at each pass.

David

7. ### (Q)Encephaloid MartiniValued Senior Member

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This electron in close orbit with the neutron, is it a meson?

They are all fermions. Neutrons and protons are hadrons. The electron is a lepton.

If so which nuclear force does it belong to? Weak or strong?

Electrons are held in orbit by the electrical Coulomb force between charged particles. Neutrons are bound by the weak force.

8. ### DarkDAVERegistered Member

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Electron.......0.00..............9.1094E-31
Proton.........8.00E-16.......1.6726E-27
Neutron.......8.00E-16.......1.6749E-27

Proton mass + electron mass = 1.6735E-27 kg only !!
Actual Neutron mass...............= 1.6749E-27 kg

If a neutron truely is a proton with an electron in close orbit...

How come it has more mass than a proton and an electron combined?

Regards, David

Last edited: Apr 14, 2002
9. ### James RJust this guy, you know?Staff Member

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37,550
(Q):

In this instance I'm afraid you're on the wrong track.

<i>A neutron is basically a proton with an electron in close orbit.</i>

No it isn't. Both neutrons and protons are made up of quarks.

It is very hard to pin down the radius of a neutron or proton, since the concept is ill-defined at the quantum level. A neutron, for example, is in a sense a smeared-out fuzzy ball of probability. It is not a solid, billiard-ball-like object.

The strong nuclear force which holds protons and neutrons together operates at distances less than about 10<sup>-15</sup> m. The radius values quoted are a kind of average which is a bit less than that.

Incidentally, electrons are currently thought to have zero radius - literally no size.

10. ### Adam§Þ@ç€ MØnk€¥Registered Senior Member

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I'm not sure I can see electrons having no radius (little joke there).

11. ### DarkDAVERegistered Member

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............LENGTH......MASS

.............m................kg

Plank....1.62E-35.....2.1767E-08

But protons and neutrons are heavier and bigger than plank length and mass. Surely that allows them to have a specific radius?

But getting back to the question... do protons and neutrons share identical radius? Or is the Neutron slightly larger?

I remembered reading somewhere that mesons ocilate between protons and to make each proton a neutron during each pass... so a heliem neucleus is made up of protons that constantly swap states with other protons... taking turns to become a neutron each time a negative charge messon takes turns on the diferent protons.

I was under the impression that mesons are electrons that exist within the nucleus.

David

Last edited: Apr 13, 2002
12. ### Adam§Þ@ç€ MØnk€¥Registered Senior Member

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How could an electron have no radius/size if it has mass?

13. ### DarkDAVERegistered Member

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Electrons are smaller than plank's length so it plays by the rules of quantum theory and not newton's rules.

A black hole is the same thing... it has no radius... dont confuse this with the schwartschild radius. The singularity it self has no radius but there is a specific mass and gravitational level.

Electrons are points like black holes are but electrons unlike blackholes exist in several points in space simultaneusly. This is called quantum weirdness.

Electrons ocupy several points in space and these points are suficiently spread out to be wider than the schartschild radius of the electron so it doesnt colapse into a black hole.

Hope this helps! And if you dont understand half of the terms i used... i suggest you do your own research at http://www.physlink.com

Anyways! Having said all that... can some one please tell me if neutrons do infact have equal radius to protons? And please explain why or why not.

Also please read all the replies here before you post so that you can take into account of everything i have already said. Such as the numbers and arguements i have already pointed out.

Regards, David

14. ### (Q)Encephaloid MartiniValued Senior Member

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James R

(Q):

In this instance I'm afraid you're on the wrong track.

A neutron is basically a proton with an electron in close orbit.

No it isn't. Both neutrons and protons are made up of quarks.

I said they were made up of quarks and so did you. How is that the wrong track?

Q said:

Neutrons are bound by the weak force.

Whoops! I see now. You're right James. My mistake. Neutrons are bound by the 'strong force' which occurs via exchange of mesons which are the basic one quark/one antiquark zero spin bosons.

James said:

It is very hard to pin down the radius of a neutron or proton, since the concept is ill-defined at the quantum level.

Not really. The radius of a neutron can be derived from the potential energy using the orbital conception that a neutron is made of a core and a shell. This approach provides a very simple way to get the neutrons classical radius, whose value is in agreement with experimental data.

If a neutron truely is a proton with an electron in close orbit...

How come it has more mass than a proton and an electron combined?

When a neutron decays into a proton, an electron is 'fired' out moving at a high speed thus creating a lot of kinetic energy. The kinetic energy of the fast moving electron and the energy of the neutrino appear as "binding energy." All three particles (proton, electron, antineutrino) can share this energy in many ways and in doing so take on a range of values while still obeying energy and momentum conservation. Some energy is also carried away during the decay hence there will be a difference in the masses.

Nuetrons are essentailly protons with a close orbiting electron in the orbital conception. And as James R has pointed out, the electron basically has no radius and at the quantum level is in a sense a smeared-out fuzzy ball of probability. That is why their radii are almost the same.

15. ### John Devers(AVATAR)Registered Senior Member

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Hi Dave, In physics singularities and points are not the same.

16. ### James RJust this guy, you know?Staff Member

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(Q):

Let me repeat - your idea that a neutron is somehow made of an electron and a proton is completely incorrect.

Protons and neutrons are both made of up and down quarks. A proton consists of two up quarks and one down quark (uud), whereas a neutron consists of two down quarks and one up quark (udd). <b>A neutron has no electrons inside it.</b>

For others:

I thought I'd already answered the radius question. Since a neutron is not a solid ball, but actually a group of three particles, the radius is difficult to define. The values quoted are always an average value. I <i>think</i>, for what it's worth, that the radii of a proton and a neutron in these terms are approximately equal, but it's something you'll almost never hear a physicist talking about because the concept is ill-defined at the quantum level.

17. ### Adam§Þ@ç€ MØnk€¥Registered Senior Member

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But the radius of an electron, which has mass?

18. ### James RJust this guy, you know?Staff Member

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The radius of an electron is beyond our ability to probe. There's a theoretical construct called the <i>classical electron radius</i> which is useful in some instances, but isn't a real measure. I can't remember its exact value.

19. ### Adam§Þ@ç€ MØnk€¥Registered Senior Member

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More bloody unanswered questions! Physics needs to get itself sorted out PDQ!

20. ### wet1WandererRegistered Senior Member

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When this question came up about radii sizes I said, "Well let me look and see what I can find". I found gobs of info but nowhere did I find it flat out stated that the neutron or proton is of such and such size. It became appearent after a while that it is danced around because it is a vague value. This tends to support James R's explainations in my mind. If there was a flat out "value" it would say so. That it doesn't speaks volumes for what James R has put forth...

21. ### DarkDAVERegistered Member

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Electrons and Blackhole Singularities are not the same thing. I never implied that.

However... Electrons and Blackhole singularities ARE points but of a diferent kind of points.

The Electron's virtual radius (area of space ocupied by fuzzy probabilities) cover an area of space larger than it's own Schartschild radius... this is why it does not colapse into a black hole singularity.

The black hole singularity on the other hand has too much mass to exist in a quantum state of ocupying multiple points in space simultaneusly in a fuzzy probability nature. It's mass exeeds plank's mass.

The black hole exists at a single point in space with a 100% probability of being there. The Electron exists as multiple points in space with varying probabilities at various points. Both however... have one thing in common... they are both points and therefore have no actual radius although they both have mass.

David

22. ### DarkDAVERegistered Member

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Also regarding the gentlemen's comment that the thread not having any values of radiuses... kindly scroll up... i have as a matter of fact stated several times the radiuses that are officialy stated in

click on the REFERENCE SECTION and click on REFERENCES
also the section there called CONSTANTS are also useful.

All my values were picked from there. For some reason... the proton and neutron radiuses listed there are identical, but they are only up to 4 decimal places.

Im getting the impression now that a Neutron contains a proton , electron and an anti-neutrino??? is this what youre all implying?

Regards, David

23. ### (Q)Encephaloid MartiniValued Senior Member

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Im getting the impression now that a Neutron contains a proton , electron and an anti-neutrino??? is this what youre all implying?

That is true, metaphorically. The neutron is made up of quarks, however the neutron decays into a proton, creating and releasing the antineutrino and electron. The proton remains and consists of quarks.