questionposter Posted September 8, 2011 Posted September 8, 2011 (edited) I guess there's some amount of energy confining an electron to an atom, so what would it take for an electron to actually fall into or get pushed into the nucleus? Or does it just never happen? Why does it only happen with particle accelerators? Can I make an atom so massive that the size of the nucleus meets the boundary of an electron? And if that happens, will nothing or something happen? Edited September 8, 2011 by questionposter
ajb Posted September 8, 2011 Posted September 8, 2011 Are you thinking of electron capture? It is thought of as the inverse process to beta decay.
swansont Posted September 8, 2011 Posted September 8, 2011 Electrons spend some time in the nucleus, or (in classically thinking of them as having trajectories) pass through the nucleus from time to time. The cross section for interaction is small and nothing will happen that's not energetically favorable, so you will only see the electron capture occur under certain conditions. The electron is bound because it has a mechanical energy that is less than zero. But energy does not confine an electron. The electromagnetic force does that.
Realitycheck Posted September 9, 2011 Posted September 9, 2011 The size of an electron's orbit is about 20-150 thousand times greater than the diameter of the nucleus. Once you get to atomic numbers greater than 100, you start running into problems with the atoms being unstable and falling apart rather quickly.
questionposter Posted September 9, 2011 Author Posted September 9, 2011 Electrons spend some time in the nucleus, or (in classically thinking of them as having trajectories) pass through the nucleus from time to time. The cross section for interaction is small and nothing will happen that's not energetically favorable, so you will only see the electron capture occur under certain conditions. The electron is bound because it has a mechanical energy that is less than zero. But energy does not confine an electron. The electromagnetic force does that. Electrons pass into the nucleus but because of the wave mechanical motions the waves of the protons and electrons never meet, but what's happening in a neutron star or the formation of a black hole that pushes an electron into the nucleus? Why does it only happen with those conditions?
Realitycheck Posted September 9, 2011 Posted September 9, 2011 The overwhelming gravity just completely collapses the atomic structure into one big heap, eliminating the relatively huge amount of space between nucleus and electron. Proton and electron merge into neutrons. Everything fuses together effectively into one completely solid "singularity".
swansont Posted September 9, 2011 Posted September 9, 2011 In neutron star it's more than forcing the electrons into the nucleus. They are fermions and can't be in the same state (Pauli exclusion principle), so you have to overcome the degeneracy pressure http://en.wikipedia.org/wiki/Electron_degeneracy_pressure
questionposter Posted September 9, 2011 Author Posted September 9, 2011 In neutron star it's more than forcing the electrons into the nucleus. They are fermions and can't be in the same state (Pauli exclusion principle), so you have to overcome the degeneracy pressure http://en.wikipedia....neracy_pressure How do the electrons not even get forced into the nucleus and combine to form neutrons and neutrinos even at the point of a neutron star? Isn't their position a lot more localized? Or what does it take to force an electron into the nucleus so that it reacts with a proton to make other particles?
swansont Posted September 9, 2011 Posted September 9, 2011 How do the electrons not even get forced into the nucleus and combine to form neutrons and neutrinos even at the point of a neutron star? Isn't their position a lot more localized? 1. "not even get forced into the nucleus"? I can't parse this. Are you asking about the Pauli exclusion principle and degeneracy pressure? Or what does it take to force an electron into the nucleus so that it reacts with a proton to make other particles? 2. Did ajb's links not address this?
questionposter Posted September 9, 2011 Author Posted September 9, 2011 1. "not even get forced into the nucleus"? I can't parse this. Are you asking about the Pauli exclusion principle and degeneracy pressure? Dude, is math your first language and English your second? Just look at it. "Not even" is pretty easy to understand, no wonder I ask so many questions, you really did learn math first. "not even" emphasizes that even in the presence of an understood circumstance, the expected does not happen. 2. Did ajb's links not address this? I don't completely understand it or why, but it seems like when a neutron decays, for some random energy reason the electron falls into the nucleus into a proton, but why is it so easy for an electron to fall into the nucleus there and not when there's a gravitational pull of like -(10^5x^2)? So what if there's a slight energy difference?
khaled Posted September 10, 2011 Posted September 10, 2011 Dude, is math your first language and English your second? Just look at it. "Not even" is pretty easy to understand, no wonder I ask so many questions, you really did learn math first. "not even" emphasizes that even in the presence of an understood circumstance, the expected does not happen. I think that ajb and swansont tried their best to understand your question, If you are trying to understand how electrons move around. You should think about the works such as Einstein Relativity, which explain how planets orbit around a star just like how it explain how electrons orbit around a nucleus ... 2 forces inverse to each others' directions which are orthogonal to the tangent, one pulls it down to the nucleus, and one pulse it away .. in symmetry they keep it in its orbit, if one of the two forces exceed, then it either is pulled away or pulled down ... hard enough to understand ..?
questionposter Posted September 10, 2011 Author Posted September 10, 2011 (edited) I think that ajb and swansont tried their best to understand your question, If you are trying to understand how electrons move around. You should think about the works such as Einstein Relativity, which explain how planets orbit around a star just like how it explain how electrons orbit around a nucleus ... 2 forces inverse to each others' directions which are orthogonal to the tangent, one pulls it down to the nucleus, and one pulse it away .. in symmetry they keep it in its orbit, if one of the two forces exceed, then it either is pulled away or pulled down ... hard enough to understand ..? No, I don't think it's quite that. Since I"m asking so many questions, they should assume that I don't know as much as them, so why do you think they would continue to use knowledge that they know they can only learn at the level of physics they are at? Beats me, although for some reason I think that's more true for Swansont than ajb. But also, what "force" is preventing two attractive forces from not running into each other? What actual "force" is there keeping an electron from forming a neutron with a proton? Don't you think a neutron star contains a little tiny bit more force pulling everything together than a missing decayed neutron? Does getting rid of a neutron "make room" for the electron? I'm not asking so much for the mathematical concept, that's latter, I'm talking about the concepts that all that math is based on. Like how many quantum mechanics are based on the concept of wave-particle duality. Edited September 10, 2011 by questionposter
khaled Posted September 10, 2011 Posted September 10, 2011 (edited) No, I don't think it's quite that. Since I"m asking so many questions, they should assume that I don't know as much as them, so why do you think they would continue to use knowledge that they know they can only learn at the level of physics they are at? Beats me, although for some reason I think that's more true for Swansont than ajb. They are both experts, and they know what they talk about. It's your problem that you ask for a high-level atomic physics question, without the decent knowledge in atomic physics ... But also, what "force" is preventing two attractive forces from not running into each other? What actual "force" is there keeping an electron from forming a neutron with a proton? Don't you think a neutron star contains a little tiny bit more force pulling everything together than a missing decayed neutron? Does getting rid of a neutron "make room" for the electron? There is no such thing as "the force that prevents", we have two forces on the object, each have the inverse direction, and the same power. Consider them like two vectors, a vector and its inverse, when they add up, we get Zero. I'm not asking so much for the mathematical concept, that's latter, I'm talking about the concepts that all that math is based on. Like how many quantum mechanics are based on the concept of wave-particle duality. This is a physics forums, we are not talking about mathematics. Even though, without mathematics, you can't work in physics .. Mathematics is not based on concepts from physics, it has its own roots in history, Wikipedia:History of Mathematics ... Moreover, Quantum theory is based on having a hidden object, and observer (that can observe something about the object), the object's real state, and the object's state from our perspective (superposition) over time. A simple example to understand is Wikipedia:Schrodinger's cat. The hidden object is the cat, the observer for example is opening the box, the real state is either life or dead, the superposition is alive and dead. Edited September 10, 2011 by khaled
questionposter Posted September 10, 2011 Author Posted September 10, 2011 (edited) They are both experts, and they know what they talk about. It's your problem that you ask for a high-level atomic physics question, without the decent knowledge in atomic physics ... But if it's that simple of a question, why can't he answer it or just say he doesn't know? He's the one who's calling himself an expert, he should be able to answer questions clearly. It's not my fault he took all that physics and told everyone he's an expert on the physics forums and told everyone he can answer questions. If it's high-school physics he should be able to answer it clearly, otherwise I don't see an excuse why a masters or Ph. D. can't answer a "high-school" level question. That's like I said before, like saying Isaac Newton couldn't do 15+7. Yeah, he invented calculus an all sorts of crazy math, but that doesn't impair his ability to do the basic things. There is no such thing as "the force that prevents", we have two forces on the object, each have the inverse direction, and the same power.Consider them like two vectors, a vector and its inverse, when they add up, we get Zero. Gravity is preventing me from floating up right now. This is a physics forums, we are not talking about mathematics. Even though, without mathematics, you can't work in physics .. Mathematics is not based on concepts from physics, it has its own roots in history, Wikipedia:History of Mathematics ... Moreover, Quantum theory is based on having a hidden object, and observer (that can observe something about the object), the object's real state, and the object's state from our perspective (superposition) over time. A simple example to understand is Wikipedia:Schrodinger's cat. The hidden object is the cat, the observer for example is opening the box, the real state is either life or dead, the superposition is alive and dead. So what? All that does is just support that the mathematics of QM are based upon the concepts and measurements. We say that particles acted like waves, so we looked into using sine waves to describe them, and it worked. Edited September 10, 2011 by questionposter
csmyth3025 Posted September 10, 2011 Posted September 10, 2011 But if it's that simple of a question, why can't he answer it or just say he doesn't know? He's the one who's calling himself an expert, he should be able to answer questions clearly. It's not my fault he took all that physics and told everyone he's an expert on the physics forums and told everyone he can answer questions. If it's high-school physics he should be able to answer it clearly, otherwise I don't see an excuse why a masters or Ph. D. can't answer a "high-school" level question. That's like I said before, like saying Isaac Newton couldn't do 15+7. Yeah, he invented calculus an all sorts of crazy math, but that doesn't impair his ability to do the basic things. You've been provided with links that answers your question by ajb here: http://en.wikipedia....lectron_capture and by Swansont here: http://en.wikipedia....neracy_pressure You might also want to review Wikipedia's more generalized article on degenerate matter here: http://en.wikipedia....generate_matter These articles are usually written for the layman with a high school education, although some can be quite advanced. They provide many links that can elaborate on different points made in the articles. They also provide a list of references if you're serious about researching the subject. Swansont and ajb have repeatedly (and patiently) given you answers to your questions and they've provided links so that you can understand their answers. The problem here is that you're either not reading the links or you don't understand them. If you don't understand a specific part of the articles you've been provided, then say so and someone will attempt to answer your question. The members of this forum are not your tutors. I can assure you that both ajb and Swansont know what they're talking about. Questioning their knowledge because you don't understand the material you've been provided is both impolite and self-defeating. Eventually people will tire of you rhetoric and simply stop replying to your posts. Chris 2
questionposter Posted September 10, 2011 Author Posted September 10, 2011 (edited) You've been provided with links that answers your question by ajb here: http://en.wikipedia....lectron_capture and by Swansont here: http://en.wikipedia....neracy_pressure You might also want to review Wikipedia's more generalized article on degenerate matter here: http://en.wikipedia....generate_matter These articles are usually written for the layman with a high school education, although some can be quite advanced. They provide many links that can elaborate on different points made in the articles. They also provide a list of references if you're serious about researching the subject. Swansont and ajb have repeatedly (and patiently) given you answers to your questions and they've provided links so that you can understand their answers. The problem here is that you're either not reading the links or you don't understand them. If you don't understand a specific part of the articles you've been provided, then say so and someone will attempt to answer your question. The members of this forum are not your tutors. I can assure you that both ajb and Swansont know what they're talking about. Questioning their knowledge because you don't understand the material you've been provided is both impolite and self-defeating. Eventually people will tire of you rhetoric and simply stop replying to your posts. Chris ajb gave 1 link to what he thinks I might be talking about, which still doesn't answer it, because I'm talking about forcing an electron into the nucleus, the amount of force it takes to push an electron into the nucleus, not making room for it. I'm questioning not swan's "knowledge" of physics, but what he is actually doing here on this topic, which to this point isn't helping much. I say "1+1=2 right?", and then swan says "no, Let's say N. N is the smallest set satisfying these postulates: 1 is in N. If x is in N, then its "successor" x' is in N. There is no x such that x' = 1. If x isn't 1, then there is a y in N such that y' = x. If S is a subset of N, 1 is in S, and the implication (x in S => x' in S) holds, then S = N.Then you have to define addition recursively: Def: Let a and b be in N. If b = 1, then define a + b = a' (using P1 and P2). If b isn't 1, then let c' = b, with c in N (using P4), and define a + b = (a + c)'.Then you have to define 2: Def: 2 = 1'2 is in N by P1, P2, and the definition of 2.Theorem: 1 + 1 = 2Proof: Use the first part of the definition of + with a = b = 1. Then 1 + 1 = 1' = 2 Q.E.D." Edited September 10, 2011 by questionposter
ajb Posted September 10, 2011 Posted September 10, 2011 I think that the closest process to what you are describing is electron capture. I think your question really based on classical thinking and so is not really very easy to answer in classical terms. There is the notion of on ionization energy, which is the energy to liberate an electron from an atom. This is a measure of "how bound" the electrons are to the atom.
swansont Posted September 10, 2011 Posted September 10, 2011 ajb gave 1 link to what he thinks I might be talking about, which still doesn't answer it, because I'm talking about forcing an electron into the nucleus, the amount of force it takes to push an electron into the nucleus, not making room for it. You did not make this clear. You asked "what would it take for an electron to actually fall into or get pushed into the nucleus" (emphasis added). Blaming others for this confusion — expecting us to figure out that you meant something other than what you wrote — doesn't help matters. Further, the people answering you are not clairvoyant and don't know how much physics you already know. Getting all pissy about it, though? I suggest you (re)read csmyth3025's post and pay close attention to the conclusion.
questionposter Posted September 11, 2011 Author Posted September 11, 2011 I think that the closest process to what you are describing is electron capture. I think your question really based on classical thinking and so is not really very easy to answer in classical terms. There is the notion of on ionization energy, which is the energy to liberate an electron from an atom. This is a measure of "how bound" the electrons are to the atom. What about what's happening when matter is being forced into a density past the point of a neutron star into a black hole? Do the electrons ever get "forced" in, or is there some unknown thing that prevents that and instead forces them outward? It seems strange that a particle accelerator could do this but the force of a neutron star isn't. But I guess if it doesn't happen in a neutron star or beyond, then electron capture I guess is the limit of the answer, but even if it is, it's still strange a particle accellerater could do it and not a forming black hole. You did not make this clear. You asked "what would it take for an electron to actually fall into or get pushed into the nucleus" (emphasis added). Blaming others for this confusion — expecting us to figure out that you meant something other than what you wrote — doesn't help matters. Further, the people answering you are not clairvoyant and don't know how much physics you already know. Getting all pissy about it, though? I suggest you (re)read csmyth3025's post and pay close attention to the conclusion. w/e ajb summarized in a couple sentences what took you like 10 posts, so you tell me.
ajb Posted September 11, 2011 Posted September 11, 2011 What about what's happening when matter is being forced into a density past the point of a neutron star into a black hole? The structure of neutron stars is not really that well understood. Wikipedia outlines the expected structure of neutron stars based on mathematical models here. The structure is a mix of condensed matter physics and particle physics,very interesting and the core probability consists of quark matter, whatever that is exactly. Maybe a quark-gluon plasma or some colour superconducting material. This is physics in the extreme. As for the details of what happens at the point of forming a black hole I doubt you will find a very clear answer anywhere. The theory requires knowledge of physics in extreme gravitational fields and at some point quantum gravity. It is expected that quantum gravity will regulate the classical singularity at the centre of a black hole. Details here are missing any things are inherently speculative as we do not understand quantum gravity.
questionposter Posted September 11, 2011 Author Posted September 11, 2011 (edited) The structure of neutron stars is not really that well understood. Wikipedia outlines the expected structure of neutron stars based on mathematical models here. The structure is a mix of condensed matter physics and particle physics,very interesting and the core probability consists of quark matter, whatever that is exactly. Maybe a quark-gluon plasma or some colour superconducting material. This is physics in the extreme. As for the details of what happens at the point of forming a black hole I doubt you will find a very clear answer anywhere. The theory requires knowledge of physics in extreme gravitational fields and at some point quantum gravity. It is expected that quantum gravity will regulate the classical singularity at the centre of a black hole. Details here are missing any things are inherently speculative as we do not understand quantum gravity. Wait, I think I found a contradiction with quark matter. In the wikipedia article you provided http://en.wikipedia....ki/Quark_matter it says "billions of times higher than could be produced in laboratories", but then in THIS article it says quark gluon plasma as already been made http://en.wikipedia....rk-gluon_plasma and that they heat material up to 4 trillion degrees. Otherwise, it seems the extent of what I'm talking about it seems to be particle colliders and electron capturing with our current knowledge. Although, I can't find the article, but there was some article I read sometime that said one possible explanation for fusion in the sun is a kind of quantum teleportation, where the protons are forced so close to each other that their boundaries of their wave functions exceed each other and so they combine to form a bigger nucleus. Is it possible that electrons can do the same in order to make those exotic "heavy" electrons? I mean there is a difference between this and a high-energy particle collide, because if you collide two protons, they don't always form a nucleus, they can also spray out into a bunch of smaller particles. Edited September 11, 2011 by questionposter
ajb Posted September 12, 2011 Posted September 12, 2011 Wait, I think I found a contradiction with quark matter. You have found a contradiction in the Wikipedia articles on quark matter. I am not hugely surprised that, just shows how we must take care using Wikipedia. Although, I can't find the article, but there was some article I read sometime that said one possible explanation for fusion in the sun is a kind of quantum teleportation, where the protons are forced so close to each other that their boundaries of their wave functions exceed each other and so they combine to form a bigger nucleus. I think that is an ok way to think about it. On the scale of nuclear physics quantum mechanics is dominant and one should think about wave functions rather that little billiard balls. Protons repel each other due to their electric charge. They can fuse to for nuclei at temperatures and pressures slightly lower that you would expect classically due to quantum tunnelling. They don't have to overcome the classical repulsion completely, but enough so that they can tunnel through this. Is it possible that electrons can do the same in order to make those exotic "heavy" electrons? I mean there is a difference between this and a high-energy particle collide, because if you collide two protons, they don't always form a nucleus, they can also spray out into a bunch of smaller particles. Sort of. Two electrons that are weakly interacting and are at low temperature can form a quasi-particle state with energy lower than the Fermi energy. These quasi-particles are bosons and go under the name of Cooper pairs. These quasi-particles are very weakly bound and are easily broken by thermal energy and so only form in very cold systems. The Cooper pairs are important in the theory of superconductivity.
questionposter Posted September 12, 2011 Author Posted September 12, 2011 Sort of. Two electrons that are weakly interacting and are at low temperature can form a quasi-particle state with energy lower than the Fermi energy. These quasi-particles are bosons and go under the name of Cooper pairs. These quasi-particles are very weakly bound and are easily broken by thermal energy and so only form in very cold systems. The Cooper pairs are important in the theory of superconductivity. So scientists still have no idea why those heavy particles form?
csmyth3025 Posted September 13, 2011 Posted September 13, 2011 So scientists still have no idea why those heavy particles form? The Wikipedia link that ajb provided on Cooper pairs explains the basic concepts involved with the BCS Theory - first proposed by Bardeen, Cooper, and Schrieffer (BCS) in 1957. The Wikipedia article on BCS Theory can be found here: http://en.wikipedia....wiki/BCS_theory Chris ...I can't find the article, but there was some article I read sometime that said one possible explanation for fusion in the sun is a kind of quantum teleportation, where the protons are forced so close to each other that their boundaries of their wave functions exceed each other and so they combine to form a bigger nucleus... You're probably thinking of the proton-proton chain reaction thought to occur in stars like our sun: The theory that proton–proton reactions were the basic principle by which the Sun and other stars burn was advocated by Arthur Stanley Eddington in the 1920s. At the time, the temperature of the Sun was considered too low to overcome the Coulomb barrier. After the development of quantum mechanics, it was discovered that tunneling of the wavefunctions of the protons through the repulsive barrier allows for fusion at a lower temperature than the classical prediction. (ref. http://en.wikipedia...._Chain_Reaction ) Chris
questionposter Posted September 13, 2011 Author Posted September 13, 2011 (edited) The Wikipedia link that ajb provided on Cooper pairs explains the basic concepts involved with the BCS Theory - first proposed by Bardeen, Cooper, and Schrieffer (BCS) in 1957. The Wikipedia article on BCS Theory can be found here: http://en.wikipedia....wiki/BCS_theory No I'm not talking about electrons forming weak bonds with each other anymore, I mean literally heavy electrons, like a "tau electron" or "mau proton" or whatever that are basically the same as a proton and electron in every way except they have higher mass. Edited September 13, 2011 by questionposter
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