Notices
Results 1 to 26 of 26

Thread: why don't protons repel each other inside the nucleus

  1. #1 why don't protons repel each other inside the nucleus 
    Forum Freshman
    Join Date
    Aug 2010
    Posts
    11
    protons are said to repel each other then why don't protons repel each other inside the nucleus itself and come out.Explain in a simpler way just thirteen


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Freshman
    Join Date
    Aug 2010
    Posts
    16
    Protons repel each other but gravitation force bring them into the center of mass.


    Reply With Quote  
     

  4. #3  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by onurtuna
    Protons repel each other but gravitation force bring them into the center of mass.
    No, this is not the cause. There are more forces in nature than electro-magnetism and gravity. In this case, it is the so called strong force that keeps the protons together.
    Reply With Quote  
     

  5. #4  
    Forum Freshman
    Join Date
    Aug 2010
    Posts
    16
    Strong force hold protons together but what produces the strong force?
    Reply With Quote  
     

  6. #5  
    Forum Junior
    Join Date
    Dec 2009
    Location
    New England
    Posts
    223
    Quote Originally Posted by onurtuna
    Strong force hold protons together but what produces the strong force?
    There seems no upper limit to how many mysteries are "solved" by inventing a magic particle, force, or transformation that just shifts the mystery around. Rather than to succumb to quantum mechanics (who has the time?) we could look to the real world and how charged raindrops repel each other until they touch: then they share a common skin where all electric charge confines itself with an increased voltage. Perhaps we know more about the raindrop than the nucleus. Made-up solutions just take our eyes off the ball.
    "Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense." --Buddha (563BC-483BC)
    Reply With Quote  
     

  7. #6  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,402
    Dale, just because you can't understand a well validated explanation doesn't mean it is wrong.
    Reply With Quote  
     

  8. #7  
    Forum Junior
    Join Date
    Dec 2009
    Location
    New England
    Posts
    223
    Quote Originally Posted by Ophiolite
    Dale, just because you can't understand a well validated explanation doesn't mean it is wrong.
    I do not say that it is wrong. If it can be understood only by a quantum mechanic, then I refuse to take it on face value as any part of my own scientific foundation. It is healthier for me to view it with suspicion as I do the three-flavor solution the to anti-neutrino quandary. I see a simple alternate solution to the latter problem that suggests to me a fallibility to "well validated explanations".

    The following edit is to compensate for being a slow thinker. As a blue collar slob I hardly expect to think rightly, but just want the fun of trying. By heeding council that the strong force takes care of holding an atom together, one has obtained an answer he can recite but is left with nothing to think about.

    If a proton were fashioned like a little stick or skinny golf tee, with its center of gravity near one end and its center of positive charge at the other, they could naturally line up with the heavy end down, sharing proximity with the atomic center, thus with the charged end outward, the atom would take the shape of a bottle brush with no place for a handle. Given sufficient length to a proton, this would afford sufficient inverse square law advantage for gravity to finally outfox electrostatic repulsion. Right or wrong, this at least gave me something to think about during TV commercials. :?
    "Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense." --Buddha (563BC-483BC)
    Reply With Quote  
     

  9. #8  
    Forum Isotope
    Join Date
    Feb 2009
    Location
    Transient
    Posts
    2,913
    Quote Originally Posted by dalemiller
    Quote Originally Posted by onurtuna
    Strong force hold protons together but what produces the strong force?
    There seems no upper limit to how many mysteries are "solved" by inventing a magic particle, force, or transformation that just shifts the mystery around. Rather than to succumb to quantum mechanics (who has the time?) we could look to the real world and how charged raindrops repel each other until they touch: then they share a common skin where all electric charge confines itself with an increased voltage. Perhaps we know more about the raindrop than the nucleus. Made-up solutions just take our eyes off the ball.
    Or, perhaps when it come's to sub-atomic particles, we can't think the same way we do when we consider atomic/molecular structures. (A pair of raindrops). Simply enough, they are very different.
    Wise men speak because they have something to say; Fools, because they have to say something.
    -Plato

    Reply With Quote  
     

  10. #9 Re: why don't protons repel each other inside the nucleus 
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Kalpit Darbhe
    protons are said to repel each other then why don't protons repel each other inside the nucleus itself and come out
    They do.

    What holds protons in the nucleus is not the electromagnetic force but rather what is called the "residual strong force", which is supposed to result from the strong interaction among quarks -- but the derivation of this residual strong force from funcamental quantum chromodynamics has never been performed and is thought to involve some difficult mathematics.
    Reply With Quote  
     

  11. #10  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by onurtuna
    Protons repel each other but gravitation force bring them into the center of mass.
    This could not possibly be more wrong. Gravitation is far too for the masses and distances involved to overcome the electromagnetic repulsion among protons. Not even close.

    What is involved is the "residual strong force" among nucleons -- see earlier post.
    Reply With Quote  
     

  12. #11  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,154
    Quote Originally Posted by dalemiller
    Quote Originally Posted by onurtuna
    Strong force hold protons together but what produces the strong force?
    There seems no upper limit to how many mysteries are "solved" by inventing a magic particle, force, or transformation that just shifts the mystery around. Rather than to succumb to quantum mechanics (who has the time?) we could look to the real world and how charged raindrops repel each other until they touch: then they share a common skin where all electric charge confines itself with an increased voltage. Perhaps we know more about the raindrop than the nucleus. Made-up solutions just take our eyes off the ball.
    I think most scientists believe that eventually there will be discovered a way to unify all the 4 fundamental forces into a single force. I think it's called "unified field theory", but I could be mistaken about the name. Until then, the four force model is the most practical to use, and easiest to compare against experimental data.

    But,to answer your concern: I think most scientists are not satisfied with the plurality of forces as an explanation. It's just the best we've got right now.
    Reply With Quote  
     

  13. #12  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by kojax
    Quote Originally Posted by dalemiller
    Quote Originally Posted by onurtuna
    Strong force hold protons together but what produces the strong force?
    There seems no upper limit to how many mysteries are "solved" by inventing a magic particle, force, or transformation that just shifts the mystery around. Rather than to succumb to quantum mechanics (who has the time?) we could look to the real world and how charged raindrops repel each other until they touch: then they share a common skin where all electric charge confines itself with an increased voltage. Perhaps we know more about the raindrop than the nucleus. Made-up solutions just take our eyes off the ball.
    I think most scientists believe that eventually there will be discovered a way to unify all the 4 fundamental forces into a single force. I think it's called "unified field theory", but I could be mistaken about the name. Until then, the four force model is the most practical to use, and easiest to compare against experimental data.

    But,to answer your concern: I think most scientists are not satisfied with the plurality of forces as an explanation. It's just the best we've got right now.
    There is already a theory that unifies the electromagnetic and weak forces. It is called the electroweak theory. Salaam, Abdus and Weinberg received the 1979 Nobel Prize for formulating this theory and 'tHooft and Veldman received the 1999 prize for work showing that the theory is renormalizable.

    Then there is the theory of the strong interaction, the force among quarks. This is called quantum chromodynamics. It was developed by a number of people, most notably Gell-Mann and Zweig. Later Gross, Politzer and Wilczek developed the theory of asymptotic freedom which explains why free quarks are not regularly observed.

    A unified theory that includes both the electroweak theory and quantum chromodynamics would be called a "Grand Unified Theory" (GUT). No such theory yet exists, but there is ongoing research.

    Together quantum chromodynamics and the electroweak theory constitute the Standard Model of particle physics. This is a quantum theory. It explains pretty much everything that does not involve gravity. However, although the fundamental laws are included in this theory, it is so complicated that in fact no one has yet derived the nature of the forces that bind nucleons (the residual strong force) in the atomic nucleus from first principles based on the theory. So, which the basic rules are understood work remains to understand their implications.

    The other major fundamental theory of physics is the theory of gravity. This is general relativity. General relativity relates gravity to the curvature of spacetime, which is determined by the stress-energy tensor. GR is a deterministic theory, and therefore is inherently incompatible with quantum field theories, which are stochastic.

    While it is most certainly believed that there should exist a unified theory which would include the electroweak theory, quantum chromodynamics and general relativity as low energy approximations, no one knows how to construct such a theory. Both superstring theories and quantum loop gravity theories are attempts to develop a unified theory. Neither has yet been successful and there are many inconsistencies and apparent contradictions in them. If a consistent theory of all of these forces were to be found it would be called a "Theory of Everything" (TOE).

    The next step in either a GUT or TOE is widely believed to be an extension of the Standard Model to include additional particles in what is known as a supersymmetric theory. This is generally thought to also be necessary for most string theories. To date there is zero experimental evidence for supersymmetric particles necessary to such theories, and it is a major goal of the LHC experiments to find them.. This is in fact far more important than the search for the Higgs boson. The Higgs boson is predicted by the Standard Model and is the last predicted particle to thus far remain undetected. Confidence is pretty high that it will be found -- but confidences have come up dry before. Nevertheless the real excitement centers around whether or not supersymmetry will be confirmed. If supersymmetry does not pan out, then there will have to be some major re-thinking as to what a TOE wold look like. If the Higgs does not pan out then even the Standard Model is in some trouble. But the Standard Model has been spectacularly successful at explaining what has been seen in particle accelerators thus far, and so confidence is quite high in this regard and any changes to the model will have to relatively subtle.
    Reply With Quote  
     

  14. #13  
    Forum Bachelors Degree
    Join Date
    May 2010
    Posts
    419
    In addition to DrR 's explanation I would like to add that these various forces are only separate at 'low' temperatures/energy. At higher temp/energy they start recombining. This is the reason for the high energy accelerator research since hhigh enrgies are needed to find the exchange particles for these forces such as gluons and gravitons. The early universe just after the 'big bang' is also when these forces were last combined as one unified force.
    Reply With Quote  
     

  15. #14  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by MigL
    In addition to DrR 's explanation I would like to add that these various forces are only separate at 'low' temperatures/energy. At higher temp/energy they start recombining. This is the reason for the high energy accelerator research since hhigh enrgies are needed to find the exchange particles for these forces such as gluons and gravitons. The early universe just after the 'big bang' is also when these forces were last combined as one unified force.
    What you is probably correct, but no one really knows since there is as yet no unified theory that would include all of the known forces. So it is not correct to make this statement as a fact. It is only informed speculation.
    Reply With Quote  
     

  16. #15 why don't protons repel each other inside the nucleus 
    New Member
    Join Date
    Mar 2010
    Location
    kenmore, ny
    Posts
    1
    There are some very recent developments on the nature of gravity. The discovery is mathematically correct being based on real, known physical properties. It calculates extremely high forces within the Bohr atomic radius and yet higher forces at smaller than the radius of an electron. These forces are greater than electrostatic repulsion trying to separate the protons. Perhaps this helps to answer this threadís question.
    Reply With Quote  
     

  17. #16 Re: why don't protons repel each other inside the nucleus 
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by soaralone1
    There are some very recent developments on the nature of gravity. The discovery is mathematically correct being based on real, known physical properties. It calculates extremely high forces within the Bohr atomic radius and yet higher forces at smaller than the radius of an electron. These forces are greater than electrostatic repulsion trying to separate the protons. Perhaps this helps to answer this threadís question.
    references ?

    I would venture to say that this is purely speculative.
    Reply With Quote  
     

  18. #17  
    Forum Bachelors Degree
    Join Date
    May 2010
    Posts
    419
    Maybe I'm not as up to date on the matter of the strong nuclear force. I had never heard of the spill-over effect of gluon interaction which i assumed to be an extremely short range force acting only within the diameter of a nucleon, since the potential wall rises so steeply as to absolutely prevent the liberation of the constituent quarks.

    The last I had read about was the Yukawa (I think that was his name ???) theory which used pi-mesons as the exchange particle. But this was in the 60s or 70s because I already knew about it in the late 70s while at Brock University getting my BSc in Physics.
    Reply With Quote  
     

  19. #18  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by MigL
    Maybe I'm not as up to date on the matter of the strong nuclear force. I had never heard of the spill-over effect of gluon interaction which i assumed to be an extremely short range force acting only within the diameter of a nucleon, since the potential wall rises so steeply as to absolutely prevent the liberation of the constituent quarks.

    The last I had read about was the Yukawa (I think that was his name ???) theory which used pi-mesons as the exchange particle. But this was in the 60s or 70s because I already knew about it in the late 70s while at Brock University getting my BSc in Physics.
    Nope. gluons are of rest mass zero and so the force associated with them is not short range, but rather infinite range.
    Reply With Quote  
     

  20. #19  
    Forum Junior
    Join Date
    Mar 2008
    Posts
    267
    http://en.wikipedia.org/wiki/Gluon
    Since gluons themselves carry color charge, they participate in strong interactions. These gluon-gluon interactions constrain color fields to string-like objects called "flux tubes", which exert constant force when stretched. Due to this force, quarks are confined within composite particles called hadrons. This effectively limits the range of the strong interaction to 10−15 meters, roughly the size of an atomic nucleus. Beyond a certain distance, the energy of the flux tube binding two quarks increases linearly. At a large enough distance, it becomes energetically more favorable to pull a quark-antiquark pair out of the vacuum rather than increase the length of the flux tube.

    Gluons also share this property of being confined within hadrons. One consequence is that gluons are not directly involved in the nuclear forces between hadrons. The force mediators for these are other hadrons called mesons.
    Reply With Quote  
     

  21. #20  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by granpa
    http://en.wikipedia.org/wiki/Gluon
    Since gluons themselves carry color charge, they participate in strong interactions. These gluon-gluon interactions constrain color fields to string-like objects called "flux tubes", which exert constant force when stretched. Due to this force, quarks are confined within composite particles called hadrons. This effectively limits the range of the strong interaction to 10−15 meters, roughly the size of an atomic nucleus. Beyond a certain distance, the energy of the flux tube binding two quarks increases linearly. At a large enough distance, it becomes energetically more favorable to pull a quark-antiquark pair out of the vacuum rather than increase the length of the flux tube.

    Gluons also share this property of being confined within hadrons. One consequence is that gluons are not directly involved in the nuclear forces between hadrons. The force mediators for these are other hadrons called mesons.
    This is a description of what is called "asympotitic freedom" and in no way contradicts my statement that the force due to a gluon is long range.

    The fact that with sufficient separation one has expended sufficient eneregy to creat a new quark pair is irrelevant.

    Before you post what you believe to be a contradiction to something posted earlier it would be good idea to take the time to actually understand what you are posting.
    Reply With Quote  
     

  22. #21  
    Forum Junior
    Join Date
    Mar 2008
    Posts
    267
    lol.
    why do you assume that I was contradicting you?
    guilty conscience?
    I was just trying to help the other poster understand it.
    I felt that you didnt fully explain it.

    Just another classic example of everyone on the internet immediately assuming that everything that everyone else posts is a personal slap in the face and a challenge to a dual.

    My dueling days are over. I have better things to do with my time.
    Reply With Quote  
     

  23. #22  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by granpa
    lol.
    why do you assume that I was contradicting you?
    guilty conscience?
    I was just trying to help the other poster understand it.
    I felt that you didnt fully explain it.

    Just another classic example of everyone on the internet immediately assuming that everything that everyone else posts is a personal slap in the face and a challenge to a dual.

    My dueling days are over. I have better things to do with my time.
    I made the assumption because of the way in which you made the post and the total lack of understanding of the lack of relevance of the Wiki article to the question at hand.

    I have no guilty consicience. What I do have is an aversion to people who post things that don't undetrstand and that are in fact irrelevant or wrong in response to questions by people who are tryiing to learn something.

    In short, when you don't know what you are talking about you ought to refrain from dispensing ignorance that only serves to obfuscate.

    This is not a duel. The point is to post valid physics so that people can learn something. Posting irrlevancies does not help.
    Reply With Quote  
     

  24. #23  
    Forum Bachelors Degree
    Join Date
    May 2010
    Posts
    419
    I do understand the properties of exchange particles with respect to range. That is the reason the pi-meson was predicted to have several hundred times the mass of the electron. It needed to have an extremely short range. The fact remains that the gluon interactions then need two separate mechanisms to limit their range. The one at the nucleon diameter I understand, as DrR has stated, the energy needed for separation is enough to create another gluon set, so you never really separate them. BUT, what mechanism limits this infinite range force to the nuclear diameter, the range of the strong nuclear force which I attributed to pi-mesons?
    Reply With Quote  
     

  25. #24  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by MigL
    I do understand the properties of exchange particles with respect to range. That is the reason the pi-meson was predicted to have several hundred times the mass of the electron. It needed to have an extremely short range. The fact remains that the gluon interactions then need two separate mechanisms to limit their range. The one at the nucleon diameter I understand, as DrR has stated, the energy needed for separation is enough to create another gluon set, so you never really separate them. BUT, what mechanism limits this infinite range force to the nuclear diameter, the range of the strong nuclear force which I attributed to pi-mesons?
    The nucleus is not held together directly by the stong interaction which operates between quarks, bur rather by the residual strong force which operates among nucleons. While the residual strong force is a result of the strong interaction, no one has yet actually derived it from first principles and quantum chromodynamics. So one needs to be careful with terminology and make sure that both parties are talking about the same force. In any case the force among nucleons is not understood at the most fundamental levels. In short, I am not absolutely sure that I understand your question, and I suspect that not enough is known about the residual strong force to adequately answer your question. Perhaps a specialist in nuclear physics would have a different approach that might satisfy you.
    Reply With Quote  
     

  26. #25  
    Forum Bachelors Degree
    Join Date
    May 2010
    Posts
    419
    Well, let me see if I can clarify the question.
    The residual strong force which binds nucleons together, and which I attributed to pi-meson exchange as per the Yukawa theory, has a very short range. In the order of a nuclear diameter. The potential wall rises extremely steep at the edge of the nucleus ( it is almost a square well ) to bind the nucleons tightly. Now if we consider the Yukawa pion theory, it has a built-in range limit because of the pion's mass But the residual strong force, being attributed to spill-over gluon interaction has no built-in range limit (outside a nucleon) because it is propagated by a massless particle. What is the mechanism that limits the range of this residual or spill-over strong force to the nuclear diameter ?
    Reply With Quote  
     

  27. #26  
    Forum Junior
    Join Date
    Dec 2009
    Location
    New England
    Posts
    223
    Quote Originally Posted by Arcane_Mathematician
    (A pair of raindrops). Simply enough, they are very different.
    Oh, I knew that all the time!
    "Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense." --Buddha (563BC-483BC)
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •