Science Questions

Why don't protons stick to electrons?

Sun, 1st Nov 2009

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Question

Sarah Rogers asked:

Why don't electrons stick to protons if there’s electrons whizzing around the outside of an atom and the protons are the positive bit in the middle? Why don't the two just collapse in on each other?

Answer

Okay.  In a very simple sense, they do stick to protons as much as they can.  They're attracted to protons and so, they form atoms.  So an atom is essentially an electron stuck to proton.  What you really ask is why don't they get any close than they do?  It’s all basically to do with the fact that electrons – in fact, everything- has wave properties.  And the electron’s wavelengths are about a  similar sort of size of atom and that’s the reason why atoms are that sort of size over the order of the wavelength in electron.  And so, you can't really compress a wave any smaller than one or few wavelengths.  And so, the electron can’t get any smaller than that without actually changing its properties entirely.  So, it can't actually get any closer to the proton in the centre of the nucleus than it does and so, it’s stuck as close as it can.  You can cause – if at very high pressures-, you can cause electrons essentially to react with protons and turn into neutrons and this is what happens in neutron stars.  A neutron actually isn’t stable just lying around, in the atmosphere or in a vacuum.  It decays in about 14 minutes into an electron and proton sort of forms into a hydrogen atom.

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Sarah Raphaella Rodgers asked the Naked Scientists:

I'm a 16 year old Chemistry student. My Chemistry class has been focusing on the periodic table recently. I know that protons are positively charged, neutrons are neutral, electrons are  negatively charged and that atoms are mostly empty space. I also know for magnets opposites attract.

So why don't electrons stick to protons instead of flying around the nucleus? Magnets do it, so why can't atoms?

What do you think? Sarah Raphaella Rodgers, Mon, 26th Oct 2009

It has to do with the uncertainty principle. Because the electron cannot have a defined position in the nuclei of atoms means that it must occupy every other space within the atom in a wave of possibilities. If the electron was positioned with great certainty within the nuclei of atoms, their momenta becomes infinitely uncertaint. But instead, they seem to have energy-orbits inside of atoms which determine the chemical struture of the universe. Another interesting thing to note is that electrons could not be in the center of atoms, because if they where, matter would drastically sink in size.

We already know of nature objects which undergo this process, and they go by the name of neutron stars. In classical mechanics, electrons couple so strongly with protons that they should collapse all the time; and would in classical physics mean that every nucleus of every atom would gobble up the electrons in about 100 microseconds. Mr. Scientist, Mon, 26th Oct 2009

When I was 16 people like Einstein and Schrodinger were reassuring us that we need not worry; the Copenhagen interpretation and Quantum Theory were too weird to make any real difference. Now we are a half century into Physics becoming Quantum theory to the exclusion of reality even. Causality was abandoned because Quantum theory can't survive if we insist upon it.

There is a cause for quantum phenomena just as there is a cause for uncertainty.  Philosopher David Hume trashed causality with his view that no matter the times we observe an event and its precursor we can never be certain that such an event will follow a future precursor of the same nature. Philosopher Emanual Kant insisted that there is a cause for every event, however; it is just that we may never know that cause with certainty.

Edit: The cause of all quantum phenomena is that the electric and magnetic amplitude that space can support is a finite value; all photons peak at this value. Max Planck observed this. But because we did not demand causality, we imagined the Quantum nature of the universe without even considering its cause.

Uncertainty has been boiled down to the statement that it is impossible to know both the position and the momentum of anything absolutely. The more you know about the position of something, the less you can know about its momentum.

Books have been written about the implications of this. The link describes the cause of uncertainty. The quote below is the meat of it.

Edit: I should point out that the causes mentioned are my speculation; you won't find them in physics books.


Vern, Tue, 27th Oct 2009


The present state of physical science does not allow "why" questions. Any answer will have to be speculative. I have an answer to the question that works well for me.

There has never been found any substance of an electron that is smaller than its electromagnetic radius. This radius is much larger than a proton. So if observations are correct, and electrons only exist at their electromagnetic radius, they would consist of a hollow shell about 12 times larger than a proton. The electron would engulf the proton and form a dynamic dance with the proton's charges.

This is speculative, but it explains the observations. Vern, Tue, 27th Oct 2009



I'm afraid not. It's actually a result of two physical phenomena.


1) Pauli exclusion principle

This states that two fermions must be distinguishable i.e. you can always tell them apart. In practice, this means they must have at least one different quantum number. This restricts electrons into their shell structure. For example, consider hydrogen. The first shell (s- shell) has quantum numbers (1,1,1) and (1,1,-1). This is why two electrons, at most, can occupy the s- shell. These number combinations are easily derivable by solving the Schrodinger wave equation for hydrogen.


2) Entropy

Processes in physics tend to increase the entropy of the universe. Energy likes to go from ordered states to disordered (like how a ball wants to roll down a slope). A proton and an electron is more energetically favourable than a neutron. The decay of neutrons this way is known as beta decay. In order to 'squash' together a proton and an electron into a neutron you need to supply a large amount of energy, as well as overcome the electron degeneracy force (as you're probably going to try it with a large collection of atoms rather than waiting millions of years for a single electron to pair up). This occurs inside neutron stars. Homely Physicist, Sun, 1st Nov 2009

Principles do not cause things; principles merely describe the happenings. We tend to think of principles and theories as causes; they can not be causes; their use is in describing the happenings. I'm just trying to keep folks honest. Vern, Sun, 1st Nov 2009



I'm afraid not. It's actually a result of two physical phenomena.


1) Pauli exclusion principle

This states that two fermions must be distinguishable i.e. you can always tell them apart. In practice, this means they must have at least one different quantum number. This restricts electrons into their shell structure. For example, consider hydrogen. The first shell (s- shell) has quantum numbers (1,1,1) and (1,1,-1). This is why two electrons, at most, can occupy the s- shell. These number combinations are easily derivable by solving the Schrodinger wave equation for hydrogen.


2) Entropy

Processes in physics tend to increase the entropy of the universe. Energy likes to go from ordered states to disordered (like how a ball wants to roll down a slope). A proton and an electron is more energetically favourable than a neutron. The decay of neutrons this way is known as beta decay. In order to 'squash' together a proton and an electron into a neutron you need to supply a large amount of energy, as well as overcome the electron degeneracy force (as you're probably going to try it with a large collection of atoms rather than waiting millions of years for a single electron to pair up). This occurs inside neutron stars.


I am sure Hawking himself said the Uncertainty Principle had something to do with it.

Either way you're wrong, the pauli explusion principle has nothing to do with electrons falling into the nuclei of atoms. It's a process which eliminates one fermion energy level to another. This happens everywhere, not only inside an atom. And entropy also has nothing to do with it.
Mr. Scientist, Sun, 1st Nov 2009

Just in case you would like an example of the exclusionary principle ordinary in nature, it even happens when two electrons come close to each other in space. It's closely related to the wave function, which is actually one main reason why the electron does not fall into the nuclei of atoms; specifically because they are not located to any particular region of space, which would induce a collapse of their superpositioned states. They are ''arranged'' within their superpositioning because of energy levels. But the exclusion principle is not the prime cause of either the wave function or the fundemental reason why particles do not fall into the nuclei of atoms. Mr. Scientist, Sun, 1st Nov 2009

I knew i was right. I came across this convo on the net:

If these particles are attracted to one another, shouldn't electrons be pulled into the nucleus? I gather the reasoning is because of the strong force? If thats the case i need to understand this "strong force" better..

Mizzuno

This question is actually addressed in the Feynmann lectures, which are linked to in the physics napster thread in the General Physics forum. The answer is:

What keeps the electrons from simply falling in? : If they were in the nucleus, we would know their position precisely, which would require them to have a very large, but uncertain, momentum, i.e., a very large kinetic energy. This would cause them to break away from the nucleus. They make a compromise: they leave themselves a little room for this uncertainty and then jiggle with a certain amount of minimum motion in accordance with this rule.

It wasn't really the answer I was expecting. I was previously under the impression that the uncertainty relations were only an expression of our own limitation as subjective observers of a subatomic event, but apparently they are actually an expression of a fundamental principle governing the behavior of small particles. If you're curious, the relation used here is:

\Delta x \Delta \rho \geq \frac{h}{2\pi}

Where
x = the position of the particle,
\rho = the momentum of the particle, and
h = Planck's constant
Mr. Scientist, Sun, 1st Nov 2009

If you like to think that Quantum theory represents reality you have to invent excuses. Quarks can not exist outside nuclei, for example. Electrons dance to the uncertainty tune, etc. To me it is much easier just to accept reality as it presents itself. Vern, Sun, 1st Nov 2009

But it seems that we hve experimental evidence for these conclusions. If anything, i think reality has shaped physics for the larger part, not so much intentionally the other the way. Mr. Scientist, Sun, 1st Nov 2009


But we really don't. I started looking for experimental evidence for wave function collapse years ago. I'm still looking. None found. We have a habit of reporting our conclusions as experimental results. Sometimes it is hard to find the actual results that led the experimenters to their reported conclusions.

In every case where I have searched out the actual experiment the evidence was not there. The POS thought experiment Einstein and company proposed is still valid. Vern, Sun, 1st Nov 2009

We can measure decoherence, which is the gradual collapse of the wave function in wave-states of matter. We may not be able to directly observe the transformation because in doing so we disturb the p-field ''probability-field''. But, we know the collapse must occur as an actual transition from having matter acts as waves and then suddenly not. Mr. Scientist, Sun, 1st Nov 2009


But this is what we don't know; this is the idea in contention. Does the observed state happen at the time of observation as in wave function collapse, or does the observed state happen at the time of creation of the particles, as in the POS experiment? Vern, Sun, 1st Nov 2009

But there is very little else that can happen. Given the intantaneous change from wave to particle-nature means that there is little room other than to say there is a sudden collapse. All models have agreed with observation. Mr. Scientist, Sun, 1st Nov 2009

We don't know that there is an instantaneous transition from wave to particle. We know that there is an instantaneous transition of a previously unknown state to a known state at the time of observation. We have not yet figured out how to know the state of the previously unknown state. 

In the simple case of a photon striking a target, my speculative model has changing fields driving two points of maxima of the fields. Interaction always occurs very close to the points of maxima; the fields determine the trajectory.

Edit: Bolded text was edited for clarification. Vern, Sun, 1st Nov 2009

Though, we have what we need to know about this state, and that is it acts in every way like a particle when its not being observed. Mr. Scientist, Sun, 1st Nov 2009

I can't argue with the success of Quantum theory. It is the only theory I know that demands a change in reality when reality does not agree with it. Vern, Sun, 1st Nov 2009

I meant a wave by the way in the passage above - oops. Mr. Scientist, Sun, 1st Nov 2009

I don't mean to be contrary. I just need to explore every possibility that might offer experimental evidence that my vision of a photon is not reality. As far as I can determine the double slit experiment supports the vision. If I did not have the photon defined so that it must produce the observed results by cause and effect, I might fantasize some magical wave-particle duality.

The anatomy of a photon: A photon consists of two half cycles of electric and magnetic fields that drive points of maxima through space. The fields exist in a spatial area around the points. The changing amplitude of the fields drive the points and determine their path through space. Photon interaction happens at the points of maxima. So any observation will see the points. Edit: It is not my definition; it is Maxwell's definition.

What perplexes me is that folks don't seem to understand that. Is it that I just can't put the right words together?

Here's a schematic of the vision. It looks just like those that were in the text books when I studied electronics and nuclear instrumentation back in the 50's.

Vern, Mon, 2nd Nov 2009

I wouldn't be as bold as to suggest you cannot explain physics, if indeed it is the correct description of a photon. Physics is not easy to explain, whether it being a pet-theory or not. Mr. Scientist, Mon, 2nd Nov 2009

I have to keep reminding myself what my goal is here in this forum. It is not to point out weaknesses in Quantum theory, and it is not to promote my pet concepts. It is simply to remind folks when common misconceptions are promoted. In this case it was the misconception that there is experimental evidence that quantum states occur at observation time. Vern, Mon, 2nd Nov 2009

Fair do's. Mr. Scientist, Tue, 3rd Nov 2009

It would really be interesting if there was experimental evidence; maybe a last instant change in one of the states that is reflected in the other. I know that has been tried. All the attempts I know about failed. Vern, Tue, 3rd Nov 2009

Vern - You wrote: "There is a cause for quantum phenomena just as there is a cause for uncertainty."

I agree. SOMETHING caused an individual Uranium atom to decay. We just do not know what the hell it is. Perhaps it is a simply some sort of harmonic in the electron field that works a bit like "The Buterfly" effect.

Personally, I have become increasingly convinced our four dimensional world is entangled with one, or probably several other "Dimensions". In our universe NOTHING transits from point A to point B through an infinite number of points. I am unaware of ANY motion that does not pop in and out of our universe according to the various Plank Units.

Perhaps our universe has time movement, but not particle movement. As time progresses paricles move in and out of a timeless 'holding' dimension producing an effect something like a motion picture. litespeed, Tue, 3rd Nov 2009

Vern

I have a couple of observations concerning Quantum Mechanics that may or may not be relevant.  First, the Drake Equation shows that entangled particles are not a local phenomena.  That means that entangled particle A and entangled particle B do not change polarity symultaneously because they were both 'programed' at the time of separation.

I see no possible way to explain this other then to accept some sort of extra dimensional involvement, that theoretically could communicate faster the the speed of light. I send a series of entangled particles in your direction, followed by a similar sequence of non entagle particles. You notice the diference, and work out some sort of Morse code with the senders. Almost instantaneously you have joined a universeal communications exchange.  Of course the signal SENT to you travels at light speed. The subsequent communications is instantaneous. litespeed, Tue, 3rd Nov 2009



I think you're making a huge assumption here. I know of no experimental evidence that movement is quantized. Vern, Tue, 3rd Nov 2009



I have seen several attempts to show that this could happen. As far as I know they have all failed. I have never seen a proof for wave function collapse in the Copenhagen sense.
Vern, Tue, 3rd Nov 2009

Vern,

I agree it is a big leap. Howver, the Heisenberg Uncertanty priciple seems to support the notion. Further, I would like your discussion on Plank Units. IMHO, these seem to support a kind of granularity in our universe.  For instance, there is a minimum distance between A and B that can not be subdevided.  Similarly, Plank time seems to support a minimum unit of time that can not be subdevided.

Of course my understanding of Plank Units is very likely flawed.  However, I have actually seen explanations of the Big Bang that include things like Plank Zero is null, Plank Two is such and such proportion of the inflation etc etc.

My basic point is that it seems to me nothing in our universe EVER moves. It simply moves in and out of time.  Just me rambling.... litespeed, Tue, 3rd Nov 2009

I have not yet signed on to quantum units other than the quantum of light. That is because I have a speculative cause for How Come The Quantum that assigns the cause to a property of the photon. I guess when you dwell on a subject for a long time it kinda sets in your mind and makes it difficult to contemplate another scenario for the action in mind.

Vern, Tue, 3rd Nov 2009

Heisenberg uncertainty principle restricts measurement capabilities, not what objectively happens there - I completely disagree with such explanation by eye shutting ...
Quantum phenomenas are much more subtle (like interference), for example we can make expansion around extremely small Planck's constant (semiclassical WKB approximation) and in zeroth order we start with the classical mechanics.
So there should be already a classical explanation of such brutal property like not falling against Coulomb attraction ... and indeed there is - it is enough to remind that electron is not only a charge, but has also very strong magnetic dipole moment - is tiny magnet. So if they would try to fall into each other, while placing reference frame in the electron, proton/nucleus is moving in magnetic field of electron - there appears perpendicular Lorentz force bending the trajectory, so even classically they would have to miss each other.

The complete Lagrangian including electron's magnetic dipole moment (\mu) looks like that ( http://en.wikipedia.org/wiki/Free-fall_atomic_model ):
L =  \frac{v^2}{2}+\frac{Ze^2}{r}+\frac{Ze}{c}\left Jarek Duda, Sat, 2nd Feb 2013

Yeah, reading it I agree with homely physicist. You can't ignore the Pauli exclusion principle as that is what defined matter macroscopically. Although the Heisenberg exclusion principle is also important, but there depending on how far you want to take it. As a way of thinking or as a real property of the universe. yor_on, Sat, 2nd Feb 2013

Schrodigner picture represents complex electron dynamics as a simple wavefunction - Pauli exclusion principle only says that there cannot be multiple repelling particles in the same dynamical state.
This principle doesn't need to be artificially included - it is already there in Schrodinger equation alone: if we don't treat electrons independently, but include their interaction - use \psi(x,y) with repulsive potential, such two-electron wavefuntion has to vanish on diagonal: when potential goes to infinity.
And this principle doesn't work for attracting particles, like electron-positon pair would just annihilate ... we cannot use Pauli principle in proton-electron case.

The Heisenberg principle, on the other hand, says that measurements influence the system - affect eventual additional measurements of noncommuting observables - it concerns only extremely subtle category of phenomenas: measurements (projections - not unitary!).
But atom "works" even without measurements - without applying Heisenberg principle ...

Quantum mechanics gave physicists universal answers when they don't understand: "it's quantum", "it's uncertainty" ... but maybe we can search for the real understanding, concrete answers ... understand the underlying dynamics (like in Couder's picture). Jarek Duda, Sat, 2nd Feb 2013

Doesn't matter (ahem:) if they vanish meeting Jarek, well, as i see it :)
It's about each particle of rest mass craving a unique space-time position, not willingly sharing it with others. There is more to it naturally as with helium4 etc, but that's how I see it from a simplified definition. And without that principle matter should become chaotic as I think, and the chair might become?? (possibly :) Anti matter or matter, they are still  defined as rest mass, as I understands it.

And yeah, you hit a very delicate point there discussing HUP.

What is a 'observer'?
Does it need consciousness to be defined as such?
Or is it enough with something, interacting with something else? yor_on, Sun, 3rd Feb 2013

But there are some weird effects to it, thinking of it from the probability of finding a electron in a atom. The electron (in its orbital inside the atom) is from the point of probability 'smeared out' as I understands it. The measurement alone must then be the definition of 'where it is/was'

And that is not the exact same as defining a unique 'place' to/for each particle of rest mass. But macroscopically I find the Pauli exclusion principle to be what keeps us existent. yor_on, Sun, 3rd Feb 2013

The short answer is that a "proton and electron stuck together" does happen, in a neutron.

However, a neutron is unstable, and will break down in about 15 minutes, releasing an electron (beta particle) and proton, plus a ghost-like particle called a neutrino. This decay releases a lot of energy. So, a hydrogen atom (=proton+electron) is much more stable than a isolated neutron.

Neutrons can be stable, if they are combined into an atomic nucleus with protons in the right ratio. In this case, the strong nuclear force provides the binding force to keep the nucleus stable.

Too many neutrons, and one could decay (releasing an electron, as described above)

Too few neutrons, and an inner electron can be captured, forming a neutron, just as you asked

There are other nuclear decay paths too; for more details: http://en.wikipedia.org/wiki/Stable_nuclei

evan_au, Sun, 3rd Feb 2013


But electron and positron do will to share the same position ... while electrons avoid themselves because of Coulomb repulsion itself, and protons similarly.
Just imagine two-electron wavefunction \psi(x,y). It is extremely difficult to calculate it so usually they only consider energy corrections, but the wavefunction is also very different from for two noninteracting electrons because of the 1/|x-y| repulsive potential in this 3+3 dimensional space - it has infinite potential barrier on the diagonal: meaning electrons avoid themselves because of repulsion ("exclusion principle").

The only missing is understanding why against Coulomb attraction, electron doesn't fall into proton, but exclusion principle doesn't help for attracting particles (e.g. electron+proton->neutron).
And it doesn't have to - as I have written, it is enough to remember that electron is also relatively strong tiny magnet - it creates Lorentz force while trying to fall into proton - bending trajectory such that it will always miss.

About helium4 superfluid, shouldn't you rather say that they are bosons so these atoms should be all in the same quantum state? :)
But in fact it is just nonzero volume fluid ...
Quantum "smart sounding phrases" are great when you don't understand but need to say something ... but these are simplifications - bosons doesn't exactly choose the same state, exclusion of repulsive fermions is already there in Schrodinger equation ... we shouldn't be satisfied with such mystical answers, but need to get deeper ...

But I didn't want to - I have only pointed out that using it to explain why electron doesn't fall into nucleus is a nonsense...
Indeed "conscious?" observer seems to be extremely delicate point ... but he is made of the same atoms governed by the same physics, so extending the system to include him, the problem disappears ... and vanishes completely when we think of the whole universe as the system - the wavefunction of the universe. It no longer has an external observer, exterior to interact with, so there are no longer wavefunction collapses like measurements - we have unique objective unitary evolution.
And so we can consider objective physics to understand why the atom works - without external observers, measurements, Heisenberg principle ...

This smearing tries to forget about the particle part of wave-particle duality. But now we can measure where exactly was the electron before leaving the orbital - here is such picture made by averaging positions of many single electrons:

So physically the electron was somewhere in the orbital in the moment of being stripped off - remain both wave and particle like Couder's droplets and wavefunction describes only its averaged position density and relative phases of its wave nature.

Indeed ... and Pauli exclusion principle doesn't prevent such sticking together of two parts of matter :)
However, as you have written, because of strong interaction this state has much higher energy ... so what ground state hydrogen atom is, is just the lowest energetic state of electron-proton pair (excluding proton decay): electron cannot fall into the nucleus just because it would increase energy. Jarek Duda, Sun, 3rd Feb 2013

Part of the hydrogen electron's life *is* lived in the nucleus: its wavefunction square modulus is non-zero there; it has even the greatest value, there!
Infact |\psi|2 goes as e-r where r is the electron distance from the nucleus' centre.

For example, look for R(r) here:
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hydwf.html

and look at the first picture here:
http://users.aber.ac.uk/ruw/teach/237/shape.php
<<The radial solutions of the Schrödinger equation of the hydrogen atom, R(r), are plotted on the right. Each time the quantum number n increases, an additional node is created. At n=1, the radial function is all positive. Its maximum is at r=0, i.e. the point in space with the highest probability density of finding the electron is actually inside the nucleus! That is why the term probability density is used: As we move outward along the radius, the volume of a shell of equal thickness is getting larger and larger, thereby spreading out the probability over a larger volume. >> lightarrow, Sun, 3rd Feb 2013

Indeed the simplest Schrodinger equation leads to that the maximum of electron density is exactly where the proton is ... but this model is just one point charge in potential of another fixed point charge - greatly simplifies the real physics. In the real world electron being in the same place as proton would mean that they create neutron, but it would require relatively huge energy: 782keV.  So including strong force holding baryons together would rather remove this density maximum from the Schrödinger's ground state.

This simplest Schrödinger picture misses much more, like magnetic dipole moments, relativistic corrections, interaction with environment ... it is rather surprising that it works so well, especially as Nuclear shell model where they model this unbelievably complex internal structure of large nucleus with just a simple potential well.
Connecting with independence of environment behavior, which should be seen as thermal noise, we see how unbelievably strong this universality of Schrödinger's ground state is ...

... and indeed it should be - if we make "classical" thermodynamical considerations of corpuscular entities, it turns out that models based on the fundamental in statistical physics: maximal uncertainty principle - Maximal Entropy Random Walk, in opposite to standard "generic random walk" only approximating this principle, also leads to stationary probability density being exactly squares of coordinates of dominant eigenvector of corresponding Hamiltonian: the quantum ground state. Here is comparison of such "classical"(approximated) and "quantum"(corrected) random walks on defected lattice - the second has strong (Anderson's) localization properties:
Jarek Duda, Sun, 3rd Feb 2013

Be that how it might Jarek, but your question about measurements is one that has been on my mind too, but in the form of 'observers', and of course 'consciousness'. And it is important to define it I think. My own view of it is that as long as you define a 'observer' as 'something' being in a interaction with 'something else' the Copenhagen interpretation makes sense, and HUp seems then to be a sort of ultimate answer on the very small plane. If you on the other hand define it such as a 'measurement' always must involve something conscious, deciding to make that measurement? Then all of your objections hold water to me. yor_on, Sun, 3rd Feb 2013

As for bosons and fermions?

Helium 4 has a rest mass, but is defined as a boson according to Bose-Einstein statistics. Its nucleus has a atomic mass (u) of 4.0026 u. That makes it a member of the Pauli exclusion principle at normal temperatures as I understand, although acting (much) as a boson when as a condensate. The definition of a boson is hinging on the spin, and there the physics differ between a even (bosons) or uneven (fermions) amount of 'spins', counted up all together (net nuclear spin + electrons spin etc etc)  for whatever atom/particle under discussion, defining how the particle will act, as a boson, or as a fermion following Fermi-Dirac theory. But there are differences to 'bosons' too, or you might otherwise be able to expect helium4 to be massless, time less, and move at 'c' :) yor_on, Sun, 3rd Feb 2013

The need of consciousness of observer makes it extremely mystical ...
I think the best experiment to understand measurements is the Stern-Gerlach - it doesn't need any consciousness and we can get intuitions classically.
So imagine a particle with a randomly chosen direction of spin goes through such conditions (gradient of magnetic field) making it align in a line: to have spin up or down. The nearest to "up" the initial spin was, the larger probability - so this is measurement for "Pauli z matrix" observable - with two eigenvectors: spin up or down.
This measurement definitely modify the state: from a random one into one of two ... placing a few of them in different directions behaves accordingly to their order as Pauli matrices don't commute ...
Anyway, while we used to see them as something basic, measurements are physically quite subtle and complex phenomenas ...

Ok, let us look also at conscious observer situation - e.g. Schrödinger's cat.
So imagine there is a cat killed by practically random incident like nuclear decay and two observers: one near the cat, and the other separated - for simplicity let us imagine he is spatially separated, like a light year away.
Now after accidentally killing the cat, he will immediately become dead for the knowledge of nearby observer ... but for the knowledge of far observer, he will be in superposition of life and death ...
It seems there is a conflict here - while objectively cat is dead xor alive, it looks like these two observers use different quantum mechanics ... suggesting that QM only represents their knowledge ...
In fact accordingly to QM of far observer, the situation is rather:
(|cat is dead, near observer knows that cat is dead> + |cat is alive, near observer knows that cat is alive>)/sqrt(2)
so the atoms building the "conscious observer" becomes just part of physics around the cat ...

----------------------
About superfluid helium4 - indeed it is seen as made of bosons because of even multiplicity of 1/2 spin, but being all in the same quantum state is huge approximation here as it is just a liquid which can have practically any volume - liquid of electromagnetically binded alphas and electrons loosing the viscosity.
The situation is better for not composed bosons like photons, what is used in lasers for stimulated deexcitation ... but the essence here is to understand why the presence of photons makes it easier to release energy from excited atoms - understand their internal dynamics instead of just saying that photons are bosons ... Jarek Duda, Sun, 3rd Feb 2013

I have to admit to have understood nothing of what you have written, maybe it's outside of my knowledge possibilities.
Just for the news, you are the same J.Duda of the Phys. Rev. article you linked and of this: http://arxiv.org/abs/0910.2724 ?
lightarrow, Sun, 3rd Feb 2013

What you don't understand? I have only pointed out that this density maximum in the center is a nonsense from the point of particle physics (binding proton with electron would cost m_n-m_p-m_e=782keV). This simple Schrödinger equation ignores much more physical aspects, but still gives impressively good agreement, even in nuclear shell model - it is because the quantum ground state is something extremely universal, also from thermodynamical point of view as Maximal Entropy Random Walk shows (these papers and my last PhD thesis was about) ... Jarek Duda, Sun, 3rd Feb 2013

Jarek, what lightarrow mean is that you have had a long hard thinking about this, with friends presumably. We are new to the subject, and it might well be that we miss what you consider obvious. You keep coming back to the quantum ground state btw, can you expand on how you see that? One universal ground state, is that what you mean? And yes, spin states are a mystery to me :) How they can define matter from 'bosons'. So does your model simplify it, or explain them?
=

This random walk you're describing, would that then be a mechanism that we can foresee? It's what sets the spin states, if I get you right? But it would still be governed by probability, or are you saying that your model give us a tool for a 'classical explanation' that is predictable?
=

I'm probably jumping to conclusions here, but there is one more thing that intrigue me with your ideas. You refer to particles as possibly having 'internal clocks'. If I now assume that a particle, not atom, but let's say a electron can't be split in more parts, what does a internal clock means? That the arrow becomes a 'force' of sorts too? It seems to me that if I assumed a intrinsic time keeping for particles I also lift up time as a real 'dimension'? yor_on, Mon, 4th Feb 2013

...and this is quite simple to understand....and this is the less simple part  lightarrow, Mon, 4th Feb 2013

Probability density of the quantum ground state is universal from QM point of view because other states are excited - have higher energy and so want to release this energy, deexcitating down to the ground state - so this is kind of thermal equilibrium state (in 0K).
Stochastic models also predict some probability densities for these situations, but standard models predict different from QM (much weaker localization properties). Maximal Entropy Random Walks(MERW) allows to understand this conflict - it is because standard models only approximate the basic for thermodynamics: maximal uncertainty principle. If we do it right, there is no longer conflict - MERW also leads exactly to the ground state probability density.
It also gives natural intuition of the Born rules that probability is square of amplitude (leading to violation of Bell inequalities): in this model amplitude is probability on the end of past and simultaneously on the beginning of future - to get real probability in given moment we have to multiply them. This "fourdimensional understanding" allows also to get intuitive understanding of why quantum computers are stronger than classical: because they can "mount" qbit trajectories in both past (initialization) and future (measurements). Here is schematic picture of Shor's algoritm (description):


MERW is thermodynamical model, that means predicting the most probable evolution. It is obtained for the maximal uncertainty principle, what basically means that if there is no reason to emphasize any scenario, we should assume uniform probability distribution. So it is not about foreseeing some concrete scenario, but operating on our knowledge - like what stationary probability we should assume, or if we know where it is in one moment, what probability density we should assume after some time (propagator).
These are completely general considerations - spin is something much more subtle (approximately the direction of magnetic dipole moment).
Please ask if you have some questions ... here are slides about MERW.


It's extremely offtopic here ... while there is topic about it, maybe let us take it there - it was de Broglie's idea (see Hestenes paper), and the Couder's droplets give great intuition of such view on wave-particle duality and basic quantum phenomenas from this point of view ... Jarek Duda, Mon, 4th Feb 2013

So you do this from assuming a even probability 'density' to the universe? "we should assume uniform probability distribution". So I got it all wrong :) when I wondered if you were trying for a 'classical' (Newtonian?) definition. I will have to read up on the maximal uncertainty principle, it's new to me. As for a uniform probability it makes sense to me, as long as we ignore interactions, if that is how you mean? I'm good at jumping to conclusions :) And I like new ideas, and yours are new to me.
==

Btw, anything that can simplify or visualize my understanding of quantum logic and their effects, as you seem to imply in the other thread comparing macroscopic systems to quantum effects, are welcome to me :)

I'm still stuck on the simple experiment where we split a photon in two (down converting its energy) Getting either the 'spooky action at a distance', or 'hidden variable(s)' defining the outcome. Because I see no way identical photons, whose polarization you can't predict (50% chance either way) before the measurement, as proven experimentally, still always result in the other photon 'knowing' which way the polarization was, and setting the opposite polarization.

How would you describe that from your view? Or maybe that is outside the subject? yor_on, Tue, 5th Feb 2013

In terms of random walk, one of equivalent formulation of maximal uncertainty principle says that having absolutely no information about what trajectory the object will chose, we should assume uniform probability distribution among all possible paths - it is MERW. Another formulation is by maximizing entropy.
In physics we emphasize some scenarios by assigning them energy - replacing uniform distribution with Boltzmann distribution ... we can also consider multiple particles with interactions between them through potential (in analogous way as in quantum mechanics) ... please at least look at sources like slides before asking further (especially we are offtopic).. Jarek Duda, Tue, 5th Feb 2013

K will do.
yor_on, Tue, 5th Feb 2013


This is my own atomic structure theory. I think the space is negative charged elastic fluid . A positive particle such as proton will attract space to form a negative ball field around it. When an electron closing to a proton, this ball field pushes it away. The balance point is the diameter of the atom. Electrons does not fly around nuclear but bond by the ball field and proton forces. Since the space itself is charged, it conducts electromagnetic force such as light waves. Light wave is coming from electron vibrating in space. jccc, Sun, 11th May 2014

This magnet toy is a good demo for a hydrogen atom. https://www.youtube.com/watch?v=LyvfDzRLsiU#aid=P8fZ2oSGqsg jccc, Mon, 12th May 2014


The laws of physics at the atomic level is based on what is known as Quantum Mechanics and not on the physics that you’ve probably only learned to date, i.e. Newtonian Physics which is now known as Classical Mechanics. In the case of the atom, electrons can only exist in certain states. In those states the electrons don’t move on classical trajectories, as you might otherwise think of them moving. They are found in regions of space according to what we call the Wave Function. For the hydrogen atom the wave function contains everything that can be known about the state of the electron in the hydrogen atom. The square of the magnitude of the wave function is the probability density which is used to determine the probability of finding the electron in a particular region of space. Described in this way electrons don’t move the way you’d expect them to using classical physics. The states that the electrons can exist in are described by the wave function. For each allowed state there is an associated wave function known as an eigenstate. Each eigenstate is defined by certain numbers called quantum numbers. These numbers describe things like energy, angular momentum, spin, etc.. In chemistry these eigenstates are referred to as an Atomic Orbital. You can read about them online at
http://en.wikipedia.org/wiki/Atomic_orbital

The shapes of these orbitals are shown in this link. For the lowest energy level the electron can actually come as close to the nucleus as it wants to. I.e. the probability density at r= 0 is non-zero.


That is incorrect. The reason is as I just described it. The reason is not for the reason you give. Also it’s quite wrong and contrary to quantum mechanics to assert that electrons “must occupy every other space within the atom.” Such a thing is quite wrong in quantum mechanical terms. No electron can be said to exist in more than one place at one time. No electron can even be said to be at a place unless its position is measured and the electron is found to be there. And no. Hawking would not say such a thing. However I do agree that the Pauli exclusion principle has nothing to do with (and it’s called the “exclusion” principle, not the “expulsion” principle).


and this answer is far from being speculative as you claim it must be.



Nonsense.


Those aren’t excuses. And we do things because of their logical consistency, correspondence with experiment, etc. Not because we want things to be “easy.” If you want easy become an auto mechanic.


Wrong. We absolutely do.


Any physicist worth his salt could have and would have told you that such a search is a waste of time. The wave function and the notion of the collapse of the wave function are merely mathematical intermediaries, not physical entities. E.g. we don’t measure the wave function in the lab. We don’t directly measure a probability either. What we measure are things like The particle detector at (x=2, y=4) “clicked” and thus registered the presence of an electron at 3:33:29pm. We keep repeating that kind of thing and then add these numbers up. We then calculate a probability density. Etc.


If that’s true then it’s because you didn’t understand the theory and thus didn’t know what to look for or how to look for it. We can certainly observer nature and conclude that nature is consistent with the concept of wave function collapse.


We have a habit of reporting our conclusions as experimental results.

Who is “we”? I know of nobody that ignorant.


PmbPhy, Fri, 6th Jun 2014


That is quite incorrect. The neutron cannot be thought of that way, It can be shown that an electron cannot exist inside a neutron and exist as a neutron/electron system. I can't  recall where I came across that fact but no matter. It's a well-known fact. I had to prove it as part of my studies of quantum  mechanics. PmbPhy, Fri, 6th Jun 2014


That is quite incorrect. The neutron cannot be thought of that way, It can be shown that an electron cannot exist inside a neutron and exist as a neutron/electron system. I can't  recall where I came across that fact but no matter. It's a well-known fact. I had to prove it as part of my studies of quantum  mechanics.


There is no discrete electron-proton pair within a neutron--it is a single particle. However a neutron is the result of a proton "capturing" an electron: p+ + e− →  n  +  νe chiralSPO, Fri, 6th Jun 2014

The fact that atoms don't collapse just shows that the classical electron-proton model is inadequate. There is no "why" in nature: stuff happens, and the best we can do is to generate predictive models of what happens. The classical model of electrostatics works pretty well for widely separated charges but just doesn't describe the behaviour of electrons in an atom - and there's no reason why it should.

The test of quantum theory is whether it describes what we see at a very small scale, and reduces to the classical continuum description at the mesoscopic scale: and it does. The reverse test, attempting to describe small objects form the behaviour of large ones just doesn't work.  alancalverd, Fri, 6th Jun 2014


Not according to the Stadard Model. In particle physics the neutron is not a single particle but a system of three particles calledquarks of which there are several types. The neutron is composed of two down quarks and one up quark. When Murry Gell-Mann developed the theory of quarks it was just a nice gimmick to help describe what was being observed. Later on Gell-Mann decided to accept the reality of them as being "real" particles. Deep inelastic scattering shows that in the case of the proton the evidence suggests three lumps of charge instead of one. This is strong support for the quark model.

See see http://en.wikipedia.org/wiki/Neutron


Just because a proton can be created that way it doesn't mean that's the only way and it doesn't mean that's what a neutron "is." There are other ways to create neutrons. It is therefore wrong to identify a neutron as "that which results when a proton captures an electron." PmbPhy, Fri, 6th Jun 2014


That's equivalent to saying []Let's pretend that nature does not behave the way that we observe that it does and see what happens. That can result in anything that you'd like because what you're describing goes by another name, i.e. magic.

Magic is like anything that you'd like it to be so you're now free to create anything that you'd like. Have fun. PmbPhy, Sat, 7th Jun 2014


Why?

Each particle that exists is able to exist because it has all the properties which allow it to exist according to the laws of physics. Now you come along and say "The Enertron particle exists." which quite literally means that it exists outside the range of normal experience. That’s the ramification of assuming what you’re telling us to assume. Do you know what that’s called? I.e. do you know what we call a phenomenon that exists outside the range of normal range of experience? It has a very particular name. It’s know as the Paranormal. See http://en.wikipedia.org/wiki/Paranormal

Magic is the attempt to control or otherwise work with the paranormal. See
http://en.wikipedia.org/wiki/Magic_(paranormal)


If you’re doing it with respect to those things that exist in nature than it’s called science. If you’re creating things out of thin air which in doing so violate the laws of nature by their very existence then no. That’s not science. That’s magic.


No you didn’t. At least not yet. All you said was Let's pretend Enertron is real,.. which is the furthest thing from a model that you can get.


There’s nothing in any of your recent posts which explains anything, never mind atomic structure. You never created an “enertron”. You merely pretended it existed. When you did so and did so outside the laws of nature then you’re talking about the paranormal.

Please find a dictionary and look up the term “paranormal.”

Perhaps you have no training whatsoever in particle physics. If so then that’d explain a few things. Particle physics is a theory of elementary particles. It tells us what particles can exist and what the properties of those particles are. In this thread I’m assuming the idea situation by which there exists a theory of particles whose properties we fully know. Also in this thread I’m assuming that the theory which we’re assuming that we have is able to fully account for the existence of all particles that either exist now or can be created. I’m also assuming in this thread that this “enertron” is something you dreamed up which is something which is not on any list of currently known particles. If it is then please tell me where to find the list on which this particle exists. PmbPhy, Sat, 7th Jun 2014


You'd do it the same way that you'd prove or disprove the existance of unicorns.


What's your point? The laws of physics are indeed created by man but they describe nature whose existance man does not dictate.

Please do yourself a major favor. Study the following articles very carefully;

http://home.comcast.net/~peter.m.brown/ref/philosophy_physics.pdf
http://home.comcast.net/~peter.m.brown/ref/what_is_science.pdf PmbPhy, Sat, 7th Jun 2014



Since this is a science forum, we're all here to discuss what science currently knows.  If you'd like to discuss what you think might be discovered in the future, please keep the discussion to the New Theories forum. jpetruccelli, Sat, 7th Jun 2014


The present state of physical science does not allow "why" questions. Any answer will have to be speculative.


Why not? Science should be always allows why questions? jccc, Sat, 7th Jun 2014



No. "Why" implies an ulterior purpose. There is no evidence of one, nor that fundamental particles have any knowledge of such a purpose. Purpose is a construct of living things, not a property of their constituent atoms.

Science is concerned with "how" - though biologists may occasionally ask "why" as long as they are wary of excessive anthropomorphism. Hence the truly scientific answer to why the chicken crossed the road. alancalverd, Sat, 7th Jun 2014

Science is all about applying the scientific method to come up with models of nature.  The key term (for this discussion) is models.  Science doesn't deal with coming up with a fundamental "real" cause for everything.  All we as scientists can do it to come up with accurate models and then leave it to philosophers to argue over whether the model itself is reality or whether it is simply a model of some deeper underlying reality. 

The problem with posting ideas like "I think an electron can stick to a proton" is that there is no science to back that up.  It may or may not be a good idea, but unless you can show:

a) The theory is consistent with other existing measurements
b) The theory is testable and falsifiable

It is not even on the track to being a scientific theory. jpetruccelli, Sat, 7th Jun 2014

I never posted ideas like "I think an electron can stick to a proton".

I posted ideas like this.

"If the speed of force is c, then the speed limit is c.

A 100 miles per hour train cannot push a man move faster than 100 miles per hour.

The force we use is electromagnetic force, its speed is c. Therefore, we can never travel at light speed."

What's your comment? Do you think force has a speed?
jccc, Sat, 7th Jun 2014

Force is caused by a change in momentum which is in turn caused by the exchange of particles or fields.  The speed at which one object can exert a force on another is determined by the speed of those particles or fields.  The upper speed limit to anything we know of is the speed of light, since both fields and particles obey special relativity.  Of course, forces can travel slower.

So no, there is no "speed of force."  There is speed of objects which can transfer momentum. jpetruccelli, Sat, 7th Jun 2014



You can indeed ask why, but the best a scientist can tell you is how.

I am being very pedantic, but for a good reason: words in science all have very precise and noninterchangeable meanings. To a journalist, force, energy and power are all the same thing but they are entirely different in physics, and the difference is crucial to understanding and describing how things work.

It is arguable that Newton was still labouring under the illusion of a created universe with a purpose, and his work certainly predated the word "scientist" which was invented in 1833. It has been suggested that belief in a purposeful creator was the reason why natural philosophers  like Newton sought rational and consistent explanations, hence the theistic "why" was entangled with "how" in their minds, and actually laid the foundation for systematic investigation of what was presumed to be a systematic universe. But an atheistic view cannot assume an ultimate purpose, indefinitely consistent systematics, or that common logic, applied ad infinitum, will explain everything: you may have to accept from time to time that "that's just the way it is", and that certainly applies to quantum mechanics. 

So we observe red shift and ask how it can be explained. You can look at the known phenomena of doppler shift and general relativity, and deduce that distant objects in general are moving away from each other, which suggest that at some time they were closer together (or that space was smaller) hence there must have been a starting point before which the universe bore no resemblance to its present state. No "why" because no need for an ultimate purpose - it just is, and apparently was, so let's untangle the mechanism of "how" it got from there to here.    alancalverd, Sat, 7th Jun 2014


I used to think that was true but experience has shown me that it's not. After I took the time to sit down and look at all the questions that scientists have been asking and answering over the last hundred years I came to see how wrong I was and how wrong your assertion is. And I'm far from being the only physicists to think so too.

From The Inflationary Universe by Alan H. Guth. On page ix, the Foreword, written by Alan Lightman, reads



Please don't take this the wrong way, but I hope that you're not trying to discourage people from asking questions in a way that feels natural to them. People want to know why certain things are the way they are. E.g. if somone wishes to ask "If the entire floor in my house has the same temperature then why does the ceramic tiled floor of the bathroom colder than the wooden floor in the kitchen?" then you shouldn't try to get them to change the way they phrase it because it has a very simple answer.

The flaw in your argument is that you're only using examples which are consistent with your assertion and are igoring those which demonstrate that you're wrong. If you used the questions that Alan Guth was asking during the research which led to the inflationary theory of the universe then your argument falls apart.

I gave an example of a "Why" question recently in this forum - Why is the sky blue? is a very legitimate question which has a very direct and valid answer. The question which started this thread is also a valid question which also has a very direct and valid answer which I also gave.

Take a look at all the usolved problems in physics at
http://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics

Notice how they're phrased:
- Why is the distant universe so homogeneous when the Big Bang theory seems to predict larger measurable anisotropies of the night sky than those observed?

- Why aren't there obvious large-scale discontinuities in the electroweak vacuum if distant parts of the observable universe were causally separate when the electroweak epoch ended?

- Why is there far more matter than antimatter in the observable universe?

- Why does the zero-point energy of the vacuum not cause a large cosmological constant?

- Why is the energy density of the dark energy component of the same magnitude as the density of matter at present when the two evolve quite differently over time;

- Why does the predicted mass of the quantum vacuum have little effect on the expansion of the universe?

- Why is gravity such a weak force? It

- Why are there three generations of quarks and leptons?

etc

There are basically two different kinds of "Why?" questions. There are the kinds which are seeking deep spiritual meaning like "Why am I the person I am rather than someone else?" or "Why did I have to get cancer?"

See - http://www.merriam-webster.com/dictionary/why

The kinds that science can address are those of "cause." The kind that science cannot answer is "reason." Therefore

Science can answer the question - "What causes the sky to be blue?"

Science cannot answer the question - "What is the reason that the sky to be blue?" if by "reason" one is asking why "God" didn't make the sky red or purple
PmbPhy, Sat, 7th Jun 2014

And I don't understand why you don't want to understand that electrons in an atom are not little balls and so to describe their behaviour you have to use quantum mechanics.

--
lightarrow lightarrow, Thu, 3rd Jul 2014

how can they not attract each other and stick together?

A very crude analogy: Imagine you had an airport, with a slight indentation down towards a drain hole that is perhaps 1 inch across.
- If you place a jumbo jet on this indentation, will it be attracted towards the drain-hole? Yes, because there is an energy gradient.
- Why doesn't the jumbo jet stick there? It will stick there, unless a greater external force moves it away.
- Why doesn't the jumbo jet go down the drainhole? It's too big, and it takes a considerable amount of energy to squash it down and turn it into a drainhole plug.
evan_au, Thu, 3rd Jul 2014



I have only just picked up on this thread and haven't read it all the way through. The fact that we can even have a particle like the neutron shows that the electron can become part of the nucleus. However as this requires energy the electron cannot become part of a proton so is forced to orbit due to the spin of the proton and the spin of the electron. If it had enough energy it would form a neutron. However if this were easier as in a property defined at the big bang every particle would be neutral and no solid matter would form as atoms would not exist. The question should not be why doesn't it fall into the nucleus but why doesn't this combination more easily form neutrons. It actually has fallen as far as it can towards the nucleus. jeffreyH, Thu, 3rd Jul 2014

The energy involved in electrostatic interactions between electrons and protons is around a few electron-Volts - the level of energy that is involved in chemical reactions.
The energy involved in the nuclear force between protons or protons & neutrons is typically around a million times stronger, at Mega-electron-Volts.

So it takes an immense amount of energy to get electrons to interact with a nucleus - an amount of energy that cannot come from normal chemical reactions. For humans to achieve such an interaction, the energy would have to come from a high-powered particle accelerator.

There is another source of the necessary energy - a nucleus which is already severely stressed by having too many protons for the number of neutrons - this stress represents MeV of potential energy. There is a very small probability that such a nucleus will capture an electron, releasing the pent-up energy in a neutrino, to balance the necessary nuclear equations.

So three reasons protons don't routinely capture electrons:
- Electrons have far too little energy (by a factor of a million or so)
- Fundamental properties must balance before and after the interaction, which does not happen without production of an energetic neutrino.
- This interaction involves the weak nuclear force, which means it can take a long time...
evan_au, Fri, 4th Jul 2014

"So three reasons protons don't routinely capture electrons:
- Electrons have far too little energy (by a factor of a million or so)
- Fundamental properties must balance before and after the interaction,"
Evan you are refering to energy balance but the only stuff inside a molecule is the electrostatic charge and magnetic forces and these need to balanced.
As the inside of the molecule must balance perfectly electrically; a strong nuclear force of 10^38 G will be needed to force the like charges in the proton bundles together. Same force applies to the neutron bundle as well.  The proton bundle must be pushed away from the neutron bundle electro-magnetic by an EMF curling force of 10^ 36 G which also pushes away the electron enclosure.  As the normal repulsion of same charges force is weaker at 10^ 25 G ; this pushes the complex molecules proton bundles away from the other compound proton bundles thus the molecule is electrostatically and electromagnetically stable.
CliveS acsinuk, Fri, 4th Jul 2014

This brings up a question about neutron stars. Do they have a magnetic field? If so then is it simply electrons that cause it? The neutrons being neutrally charged are unlikely candidates. This would make the field mono-polar. jeffreyH, Fri, 4th Jul 2014

I don't know how important this is for neutron stars, but neutrons in atomic nuclei are certainly magnetic--both protons and neutrons have "nuclear spin" that results in a small magnetic field. I don't know to what extent the spins would arrange themselves to cancel out in a neutron star, but it would only take a small imbalance to have a fairly large magnetic moment. (A neutron has a spin of magnitude 1/2, some of the most out-of balance, but still stable nucleons have a spin of 7/2. Some more extreme nuclear states only last a short while (110Ag has a 12/2 nuclear spin, but a half life of only 253 days, and 43Sc has a 19/2 nuclear spin, but a half-life of only 450 ns!) chiralSPO, Fri, 4th Jul 2014

the only stuff inside a molecule is the electrostatic charge and magnetic forces and these need to balanced.
There are 4 known forces, of which the "Strong Nuclear Force" is the strongest one we know, and it provides most of the glue that holds the nucleus together against electrostatic replulsion of the protons.

As you suggest, Gravity is the weakest, and its effect can almost be ignored on a scale any less than a neutron star.

The proton bundle must be pushed away from the neutron bundle electro-magnetic
As I understand it, the protons and neutrons are mixed together in the nucleus of an atom. The neutrons do not repel each other electrostatically, but they contribute to the strong nuclear force which holds the protons together against the electrostatic repulsion of the protons.

which also pushes away the electron enclosure
The electrons enclosing the nucleus are attracted to the protons in the nucleus, due to their opposite charge. As far as I know, the effect of neutrons on electrons is much weaker than the impact of protons on electrons.

It is the wave nature of the electrons which prevent them collapsing into the nucleus.

the only stuff inside a molecule is the electrostatic charge and magnetic forces
There are other factors which must be balanced when considering nuclear interactions.

Like macroscopic interactions between particles, mass/energy and momentum are conserved.

Interactions involving the Strong Nuclear Force also must  obey CP symmetry, which permits some interactions, and forbids others.

The Weak Nuclear force has some slightly looser constraints on which interactions are permitted and sometimes violates CP symmetry, but these interactions have much lower probability, like a nucleus consuming an inner electron.

See: http://en.wikipedia.org/wiki/CP_violation#CP-symmetry evan_au, Sat, 5th Jul 2014



In the case of densely packed neutrons the strong nuclear force and gravitation probably act together to bind the mass. I think it is likely that an electron cloud produces the magnetic field and without a well defined positive component to the field would swamp the gravitational effect. In black holes this would become important. I am following any observations of G2 and Sag A* as this would confirm this if the cloud remains mainly intact. It would not matter if the gas cloud contains a host star. jeffreyH, Sat, 5th Jul 2014

I rather to be a neutron than an electron, how about you? jccc, Sun, 6th Jul 2014

Well, here is something to read about this: http://www.wired.com/2014/06/the-new-quantum-reality
And in my mind, something like this provides a much better understanding of how things work - much better than: "an equation says so" .. McKay, Sun, 6th Jul 2014



I vote de Broglie. He seems to have been sidelined and never made any further significant contributions to physics. It would be a testament to his foresight and give him more significance in the history of physics. I have for years thought quantum mechanics lacking clarity. No wonder quantum gravity has eluded physics for 100 years. jeffreyH, Sun, 6th Jul 2014

From the previously mentioned article.

"The experiments began a decade ago, when Yves Couder and colleagues at Paris Diderot University discovered that vibrating a silicon oil bath up and down at a particular frequency can induce a droplet to bounce along the surface. The droplet’s path, they found, was guided by the slanted contours of the liquid’s surface generated from the droplet’s own bounces — a mutual particle-wave interaction analogous to de Broglie’s pilot-wave concept."

In a modified form this describes gravity. jeffreyH, Sun, 6th Jul 2014


You can't really use an electron to release energy from a nucleus.
- For one thing, the electron very rarely interacts with the nucleus of an atom.
- And in those rare instances where an interaction does occur, much of the energy is carried away by the ghostly neutrino, which we can't capture as an energy source.

Combining two deuterium nuclei (or a dueterium & a tritium) to make a Helium nucleus does release a usable amount of energy.
- However, the wavelength of an electron is too long to draw the two nuclei together close enough for a nuclear reaction to occur at a usable rate.
- The wavelength of a negative muon is short enough to react deuterium nuclei together; unfortunately, the lifetime of the muon is too short to generate usable amounts of energy. (Or fortunately - if the muon were much better at catalysing a nuclear reaction between hydrogen nuclei, much of the hydrogen in the universe would already have fused to Helium...) evan_au, Mon, 7th Jul 2014



I don't think that conclusion is correct. The way I understand it:

Energy is stored in by electrical field in the nucleus, which exerts a force between the protons. But the electrical charge in the nucleus is positive, not negative.

Even more energy is stored by the strong nuclear field in the nucleus, which exerts a force between the protons and neutrons. But the strong nuclear force requires no electrical charge to function.
evan_au, Tue, 8th Jul 2014

How do you calculate "10^6 nucleus energy" out for e– + p+ → n ??

The equation E = keQ1Q2(1/rinitial–1/rfinal) gives no sensible answer if rfinal = 0 (as one might expect for the merger of the two point charges). Some theories predict charge separation within the neutron, but as far as I know, this has not been verified experimentally in any way. If I try values of about 1–2 fm as the final charge separation (approximate radius of a neutron) energy release is on the order of 2x10–13 J...  What was your calculation? What is nucleus energy? If the whole neutron were converted to energy (E = mc2), I calculate that as 1.5x10–10 J, which is not a factor of 106 different from anything... I am confused.

At any rate, we know experimentally that neutrons spontaneously decay exothermically (releasing energy) to produce electrons and protons, so unless the first law of thermodynamics doesn't apply here for some reason, I wouldn't expect the reverse reaction, your "neusion," to be exothermic. Am I missing something? chiralSPO, Thu, 10th Jul 2014

I don't have calculation. I am thinking energy is stored within atoms, not nucleus. To release all the energy, we must break down nucleus force field to destroy the atoms.

Nucleus reactions only released a fiction of the energy stored within atoms. Because by products are still atoms.

Experiment should not be too hard, if I have a lab I'll be very busy. jccc, Fri, 11th Jul 2014



The smallest atoms are Hydrogen (covalent radius around 30,000 femtometers) and Helium (radius 28,000 femtometers).

The nucleus is primarily held together by the strong nuclear force, which has a range of 1-3 femtometers. This is far less than the radius of even the smallest atom.

The distance which forms the chemical compounds in matter is determined by the quantum nature of electrons, not the nuclear force. (For gases, the Van Der Waals radius of a Hydrogen molecule is 120,000 femtometers.)

Jccc, please provide a hyperlink to the website which gave you the idea that the range of the nuclear force field is similar to the radius of an atom. (Note: "I just made it up" is not a good reference; experimental results are the best...) evan_au, Fri, 11th Jul 2014

JCC, I think some of the confusion here has to do with trying to think classically about things on the atomic scale (and especially at the nuclear scale). Picturing protons and electrons as little charged balls that move like macroscopic balls will naturally lead to paradoxical and contradictory predictions. chiralSPO, Fri, 11th Jul 2014

The experimental result which first showed the distribution of charge within the atom was conducted by Geiger & Marsden in a 5-year period around 1910.

They fired alpha particles (positive charge) at a gold foil (electrically neutral). The results can be explained by classical replusion of electric charges. This experiment was not sensitive enough to measure the strong nuclear force, which occurs on much smaller scales.

Up to that time, there were a variety of models for charge within an atom; one of them (developed by J J Thomson) looks a bit like the Jccc model.

However, as a result of these experiments, an alternative model developed by Rutherford was accepted, where the positive charge is concentrated in a very small volume at the very center of the atom. (Rutherford was the director Geiger's lab).

The idea that "The nucleus force field is larger than atom radius" was discarded about 100 years ago, based on experimental evidence.

Science does need theories, but the most useful output of a theory is identifying a method to disprove that theory.

There have been many theories proposed, and anything you can think of has probably already been tried in some form by someone else - that's why they hand out Nobel prizes for genuinely new discoveries in certain fields. So, Jccc, it's useful to look at some of the history of science, so you don't resurrect theories which are already disproven. You are welcome to propose new theories, but identify them as a "maybe", not state them as a "fact"; do post them in the "New Theories" section, and try to suggest a way that will disprove your new theory.

That just leaves this thread with finding a simple explanation of the more complex quantum theory,  which was developed over the subsequent 40 years, partly to explain why the negative electrons don't collapse into the positive nucleus. I suggest you start your historical catch-up here: http://en.wikipedia.org/wiki/Quantum_mechanics evan_au, Fri, 11th Jul 2014

For some time I was puzzled by what seemed to be a reciprocity failure between electron jumps away from and towards the nucleus.  I reasoned that if an electron was attracted towards the nucleus, it should require more energy to move it away from the nucleus than towards it.  The conclusion I eventually reached was that as this was a quantum leap, the electron could not be said to be anywhere when it was not occupying an energy level.  If the electron could not be said to be anywhere, it could not be using or exchanging energy.  Thus it made no difference which way it was going.  The energy necessary to accomplish the jump would be the same.

I would appreciate comments on my reasoning, please.
Bill S, Fri, 11th Jul 2014



Thanks for the comment and link! I read that page few times before, wish I understand the math. Also read this http://en.wikipedia.org/wiki/J._J._Thomson. I am far behind every one here, pretty depressed.  It's all your fault. jccc, Sat, 12th Jul 2014



This might help, not QM stuff. https://www.youtube.com/watch?v=LyvfDzRLsiU#aid=P8fZ2oSGqsg

It takes more force to push in than pull away. jccc, Sat, 12th Jul 2014

Quote from: evan_au

The idea that "The nucleus force field is larger than atom radius" was discarded about 100 years ago, based on experimental evidence.

Please explain the evidence, thanks.

Quote from: evan_au

Science does need theories, but the most useful output of a theory is identifying a method to disprove that theory.

How about as I suggested, beam high speed/energy electron into water, measure the energy used and the heat produced, they should be always the same according to present knowledge. If experiments show extra energy? jccc, Sat, 12th Jul 2014

2 H2o + 4e = o2 + E 

Oxygen atom nucleus has 8 protons, it attracts more energy into force field, the energy ball around it is denser than the energy ball around hydrogen atom nucleus.  Therefore, it takes higher energy electron to break down oxygen nucleus.

This give us control to only break down hydrogen atoms in the water. We don't want to break down oxygen atoms, it might produce new atoms and radiations.

Imagine a flash light type device which shoots high speed electron beams, point to a pond, dry it in minutes.

Point it to a watermelon, there is no more.

Do not let Pete have it. jccc, Sat, 12th Jul 2014



The smallest atoms are Hydrogen (covalent radius around 30,000 femtometers) and Helium (radius 28,000 femtometers).

The nucleus is primarily held together by the strong nuclear force, which has a range of 1-3 femtometers. This is far less than the radius of even the smallest atom.

The distance which forms the chemical compounds in matter is determined by the quantum nature of electrons, not the nuclear force. (For gases, the Van Der Waals radius of a Hydrogen molecule is 120,000 femtometers.)

Jccc, please provide a hyperlink to the website which gave you the idea that the range of the nuclear force field is similar to the radius of an atom. (Note: "I just made it up" is not a good reference; experimental results are the best...)

I remember we been discussing the possibility to pull the moon closer by charging it. We all agree that electrostatic force do work at long distance.

From F=kq1q2/r^2, also showed force between charged particles is always there even in long distance.

I said the nucleus force field is bigger than atom radius, means the positive charges within the nucleus produces a force field that is beyond atom radius. We can charge electron into neutral matter shows nucleus force attracts electron even out side the atom.

So what's wrong with this concept? The nucleus force field is larger than atom radius, so that atoms can form matter.

In your opinion, how big is nucleus force field? Or proton force field in a hydrogen atom?


It is widely accepted that the electrostatic force acts over long distances. I don't think anyone on this thread disputes that. When it was mentioned that the "nuclear force" exerts no significant effect at even reasonably small distances, what was meant was that the "strong force" which holds the positively charged nucleus together only acts over very, very short distances (femtometer scale)... This strong force is entirely different in nature and mechanism from the electrostatic force.

I am probably wrong here, but my intuition on this is that the strong force is related to an exchange energy of the quarks between the nucleons of the nucleus, so the effect decays exponentially with distance (e–k*r, where k is some constant; analogous to tunneling or exchanging electrons) in addition to the 1/r^2 law which arises from the fact that it spreads out in 3 dimensions. Any thoughts on this from the physicists out there? (this is just a chemist's hand-waving answer that allows me to sleep at night...) chiralSPO, Sat, 12th Jul 2014



Any thoughts on this?

I think electron is not as easy to accelerate/energize as proton, maybe beam protons into negative charged water, hoping some head on action to happen.

The net reaction we want is p + e = E. Assume all mass converted.

Never thought I will dream such a small dream, thanks for this palace!

Our future is not in the stars but in the stardusts. jccc, Sun, 13th Jul 2014



Any thoughts on this?

I think electron is not as easy to accelerate/energize as proton, maybe beam protons into negative charged water, hoping some head on action to happen.

The net reaction we want is p + e = E. Assume all mass converted.

Never thought I will dream such a small dream, thanks for this palace!

Our future is not in the stars but in the stardusts.


This is my proof, try it.

Put e on top of p, what do you see/get?  jccc, Mon, 14th Jul 2014



Positrons and electrons will annihilate each other to release much energy. Protons and electrons will not convert. There are no positrons in water. chiralSPO, Mon, 14th Jul 2014



Electrons and protons will not convert? Any proof?

Logically any opposite charges will interact.

The goal is to break down protons positive charge/force field to release stored energy.

It's like to break a bloom to release pressure air. Or cut a robber band to release bonding stuff.

The trigger can be other than electron, maybe laser beam or other particle.

This is just a theory to be tested, looks too good to be true for now. jccc, Mon, 14th Jul 2014



Proof: Electron+Proton=Hydrogen atom (or two of each will make a Hydrogen molecule, H2)

The Hydrogen atom 1H is stable, with a lifetime of at least tens of billions of years (ie much longer than Uranium - too long for us to measure in a laboratory).

So a proton & electron do not annihilate to release energy.

A Proton and an electron do interact (to form Hydrogen), and they do release energy, in the form of an ultraviolet photon from the Lyman Series.

The maximum energy released in this photon is 13.6 eV (electron Volts).

The energy remaining in the Hydrogen atom is around 940,000,000 eV.

So the interaction of a proton and an electron releases about 13.6/940,000,000 = 0.000001% of the energy in the interacting particles.

But you can't use this 13.6eV as a source of unlimited energy, as you must supply more energy than this to the equipment which rips the electron off the Hydrogen atom in the first place, and you can't convert ultraviolet photons into electricity with 100% efficiency.
evan_au, Mon, 14th Jul 2014



Interesting link, but it might be better to stick to the QM stuff to answer the OP's question. Bill S, Mon, 14th Jul 2014

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