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Thread: Atoms

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    Atoms

    How do the atoms of the Earth stop the atoms of any objects that are 'separated' from the structure of the Earth
    From passing through it?

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    Quote Originally Posted by Ear View Post
    How do the atoms of the Earth stop the atoms of any objects that are 'separated' from the structure of the Earth
    From passing through it?
    The same way they prevent themselves from passing between or through each other. Imagine a mass of balls in contact with each other and bonded together. An incoming ball from outside needs a colossal velocity to pack enough of a wallop to make more than a small ding. Only neutrinos can pass through almost uninhibited.

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    I think a basic answer (I hope I am correct) is that atoms are made up of positively charged nuclei surrounded by clouds of negatively charged electrons. So the atoms are kept apart by the Coulomb force (electromagnetic repulsion) between the electrons on the outside of each nucleus. In fact that's what we "feel" when we touch an object and feel a force preventing us from entering into the solid. In the case of liquids or gases the atoms themselves are free to move about, so you can insert your hand by pushing aside the atoms, but you can't actually penetrate the atoms.
    As above, so below

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    In terms of mass, atoms are full of space but as Jens says the answer is the charge on the electrons that in a simple model we call the shells. In ordinary experience these shells are very elastic and tough so things bounce. Or they may stick but without any atomic damage. Sometimes the atoms align into crystals. A lot of chemical interactions are prevented by oxide layers where oxygen atoms join to form stable outside skins but it’s always the electron charges that repel invasion for outside. Then you say the Earth, which is a special lump of atoms with a magnetic field that also diverts incoming charged particles, maybe that’s part of your question. The magnetic field comes from the iron core. Electromagnetic fields extend way outside the atoms, to infinity in principle, as does gravity.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Jens View Post
    I think a basic answer (I hope I am correct) is that atoms are made up of positively charged nuclei surrounded by clouds of negatively charged electrons. So the atoms are kept apart by the Coulomb force (electromagnetic repulsion) between the electrons on the outside of each nucleus.
    Importantly, for this question, they are also bonded together by sharing some of those electrons.

    In fact that's what we "feel" when we touch an object and feel a force preventing us from entering into the solid.
    That and electron degeneracy pressure.

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    If I force my hand against a wall what is happening within the atoms of my hand and the atoms of the wall that prevents my hand passing through the wall?

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    Quote Originally Posted by Ear View Post
    If I force my hand against a wall what is happening within the atoms of my hand and the atoms of the wall that prevents my hand passing through the wall?
    As Jens said, it is largely the negative charges of electrons round the atoms in the wall repelling the electrons around the atoms in your hand. (You know that opposite charges attract and like charges repel, right?)

    Combined with the fact that the atoms in your hand are held tightly together by sharing electrons. And the atoms in the wall are also held together tightly by sharing electrons.

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    Quote Originally Posted by Ear View Post
    If I force my hand against a wall what is happening within the atoms of my hand and the atoms of the wall that prevents my hand passing through the wall?
    Every normal atom has electrons with negative charge. The atom is in balance with the same number of atoms as protons in the nucleus or centre. But when two atoms come close those negative charges repel each other. In molecules electrons are shared and the atoms stick together, your hand has complex molecules but when you approach the wall the surface electrons repel the surface electrons of the wall, so you do not penetrate it. The wall is solid with the atoms packed together. This is not all so simple as that. If two pieces of metal are pressed together without their oxides, they will join or “cold weld” where they touch, in this case the atoms share electrons and form a local solid as strong as the virgin metal. Then again Ghekos can climb walls because their feet have tiny hairs that can be attracted by Van de Waal forces, so called, but they do not weld to the wall! Every material atom is a little different which is why we have chemistry !
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    How has the electron got a negative charge and how do the charges repel each other?


    if you had the technology to put a door on wall - the wall being in the 'real world' were the photons travel from the sun interact with the wall and enter my eye.
    'With the technology' a door is placed onto the wall that overrides part of the wall in my brain. When I open the door the brain now believes that air is between one side of the wall and the other and am able to walk through the doorway.

    If the atoms in my body are working in a way that they 'believe' they are walking through air would the way atoms work in the 'real world' prevent walking through the wall?

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    Quote Originally Posted by Ear View Post
    How has the electron got a negative charge and how do the charges repel each other?
    That looks like a question for the fundamental particle physicists. They might have an explanation in terms of quarks and such things.


    if you had the technology to put a door on wall - the wall being in the 'real world' were the photons travel from the sun interact with the wall and enter my eye.
    'With the technology' a door is placed onto the wall that overrides part of the wall in my brain. When I open the door the brain now believes that air is between one side of the wall and the other and am able to walk through the doorway.
    Sure, if you open a door you can walk through the opening. I don't see where belief comes in.

    If the atoms in my body are working in a way that they 'believe' they are walking through air would the way atoms work in the 'real world' prevent walking through the wall?
    Once again, I don't see where belief comes into this.

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    Quote Originally Posted by Ear View Post
    How has the electron got a negative charge and how do the charges repel each other?
    Electric charge is a fundamental property of particles. There isn't a good explanation as to why charged particles are charged. Like any one of the other kinds of charge (strong, weak) it is one of the properties we use to tell particles from each other (e.g. something with the same mass as an electron but the opposite charge is an anti-electron, also known as a positron).

    Charges repel or attract each other via the electromagnetic force. Classically the strength of the force between two electrically charged particles is proportional to the product of their charges. Thus when the charges have the same sign (both negative or both positive) the force between them is positive, which means repulsive. When the charges have opposite signs (one negative, one positive) the force between them is negative (attractive).
    See: https://en.wikipedia.org/wiki/Coulomb%27s_law

    The more complicated version of this is based on Quantum Mechanics. In this you have to consider the particles that mediate the interaction - the forces between particles are seen as an exchange of some kind of force mediating particles. The EM force is mediated by spin 1 particles - photons (spin is another fundamental property, not really linked to a classical particle turning on an axis). The interaction energy (and hence whether the force is attractive or repulsive) is related to the propagator of the system. The propagator is related to the derivative of the Lagrangian and the time component of the derivative of the Lagrangian turns out to change sign with the spin of the particle associated with the interaction. What you get is that for even spins (0, 2) like charges attract while for odd charges (1,3) like charges repel. So QM says that like electric charges repel because the underlying force carrying particles have odd spin.

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    Quote Originally Posted by Ear View Post
    if you had the technology to put a door on wall - the wall being in the 'real world' were the photons travel from the sun interact with the wall and enter my eye.
    'With the technology' a door is placed onto the wall that overrides part of the wall in my brain. When I open the door the brain now believes that air is between one side of the wall and the other and am able to walk through the doorway.

    If the atoms in my body are working in a way that they 'believe' they are walking through air would the way atoms work in the 'real world' prevent walking through the wall?
    It is not clear what you are asking here. Obviously if you put a door in a wall then you can open the door and walk through.

    But you seem to be suggesting that you could somehow fool your brain into thinking there was a door when there isn't. In which case, obviously, you could not walk through the wall. Put a VR headset on (or just close your eyes) and see if you can walk though a wall you can't see.

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    that part of the question was asked as science fiction or in a science fiction way.

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    Quote Originally Posted by Ear View Post
    that part of the question was asked as science fiction or in a science fiction way.
    Then you can make up any answer you want.

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    Is there an electro magnetic field in flat space ?

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    Quote Originally Posted by Ear View Post
    Is there an electro magnetic field in flat space ?
    The EM field is associated with charge, so if there is residual or unscreened charge then there is a an EM field.

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    Quote Originally Posted by Ear View Post
    If the atoms in my body are working in a way that they 'believe' they are walking through air would the way atoms work in the 'real world' prevent walking through the wall?
    Yes, it would. The electromagnetic force that repels them will not be eliminating by them "believing" that it doesn't exist. You would have to eliminate their charge. So for example, neutrons and neutrinos, which are electrically neutral, can go through walls.
    As above, so below

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    Danger of getting into the “reality thread”. Obviously if you dream up a virtual wall in your imagination you can walk through it in your imagination too. But you also have your experience of the external world where walls are hard. You do not need the electron explanation to experience what we all experience with walls but in physics we devise concepts and words to get deeper into an explanation. No one has seen an electron but it is a word we can agree upon to interpret the evidence. If we lived in a Matrix world , that is as a simulation in some kind of computer, then like Neo we could use belief to fly. It is probably untestable if you want to believe that but the standard model of particles we can never see with our eyes is the best model we have to explain not just walls but all our complex experiments. In that model atoms do not have beliefs that can be controlled, they have electrons and an EM field that repels other atoms. Also the weaker force gravity that attracts other atoms which is why we have an atmosphere to live in which otherwise would be repelled into space.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by profloater View Post
    Danger of getting into the “reality thread”. Obviously if you dream up a virtual wall in your imagination you can walk through it in your imagination too. But you also have your experience of the external world where walls are hard. You do not need the electron explanation to experience what we all experience with walls but in physics we devise concepts and words to get deeper into an explanation. No one has seen an electron but it is a word we can agree upon to interpret the evidence. If we lived in a Matrix world , that is as a simulation in some kind of computer, then like Neo we could use belief to fly. It is probably untestable if you want to believe that but the standard model of particles we can never see with our eyes is the best model we have to explain not just walls but all our complex experiments. In that model atoms do not have beliefs that can be controlled, they have electrons and an EM field that repels other atoms. Also the weaker force gravity that attracts other atoms which is why we have an atmosphere to live in which otherwise would be repelled into space.
    I was reading something about the delayed-choice quantum eraser implications the other day.

    I couldn't really follow it, but one interpretation is that you could walk through a wall as long as there was no record of you doing so, including in your memory. Or at least you could appear on the other side of the wall with no explanation of how you got there -you couldn't be observed in the act of walking through the wall.

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    Quote Originally Posted by kzb View Post
    I was reading something about the delayed-choice quantum eraser implications the other day.

    I couldn't really follow it, but one interpretation is that you could walk through a wall as long as there was no record of you doing so, including in your memory. Or at least you could appear on the other side of the wall with no explanation of how you got there -you couldn't be observed in the act of walking through the wall.
    There is a quantum effect called tunnelling where a particle such as an electron can jump a voltage barrier that it should not be able to do, and this leaky behaviour is important, not just a peculiarity. However it is a long way from groups of atoms passing through each other, both in scale and theoretical explanation. In other words there is within the theory a probability statement about vast numbers of particles acting together to tunnel out through a barrier. Maybe this is like evaporation or sublimation, a few atoms always escape from bulk solids or liquids but we do not see solid objects suddenly exploding into vapour at temperatures way below melting or vapourisation values. (but superheated liquids can flash off). The delayed choice quantum entanglement experiments also do not suggest the kind of superposition you ask about, namely that you could be both sides of a wall until observed. That's an extension of Shrodinger's cat thought experiment although a distant observer clearly might not know which side you are. But you need others to flesh that out.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by profloater View Post
    There is a quantum effect called tunnelling where a particle such as an electron can jump a voltage barrier that it should not be able to do, and this leaky behaviour is important, not just a peculiarity.
    Not just a voltage barrier. For example, flash memory works by causing electrons to tunnel through an insulating layer to an isolated metal gate of a transistor. Once there, the electrons can't leave and so the data storage is non-volatile. (It is erased by reversing the voltage to allow the electrons to tunnel out again.)

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    It wasn't about quantum tunnelling. It was about the quantum eraser. Also it is supposed to work with relatively macroscopic objects like buckyballs. I'll try and find the article later, I don't think it is available on line.

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    Quote Originally Posted by kzb View Post
    It wasn't about quantum tunnelling. It was about the quantum eraser. Also it is supposed to work with relatively macroscopic objects like buckyballs. I'll try and find the article later, I don't think it is available on line.
    So it sounds like the usual thing that particles behave as if they go through both slits as long as you don't observe which slit they went through (even if you do that, or hide the fact you did, after the interference pattern is recorded).

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    Quote Originally Posted by Strange View Post
    So it sounds like the usual thing that particles behave as if they go through both slits as long as you don't observe which slit they went through (even if you do that, or hide the fact you did, after the interference pattern is recorded).
    thank you for correcting. I was aiming at the walking through walls when I mentioned tunnelling because the two slits thing is a little different although it has been done with bucky balls, they still don't tunnel through walls.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by kzb View Post
    I was reading something about the delayed-choice quantum eraser implications the other day.

    I couldn't really follow it, but one interpretation is that you could walk through a wall as long as there was no record of you doing so, including in your memory. Or at least you could appear on the other side of the wall with no explanation of how you got there -you couldn't be observed in the act of walking through the wall.
    that's fine except that the atomic encounters involved are all observations so it is not just nobody observes you do it, every interaction surely counts. You would be entangled with the wall at a macro level which might be uncomfortable. And then there's temperature!
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    In principle, quantum tunneling can work with collections of particles, and composite barriers. So technically, there is a nonzero probability that you could appear on the other side of the wall without making a hole. But if you work out rough probabilities of things like that happening, you'll find that it's not something likely to happen in many orders of magnitude more than the lifetime of the universe. (Which is for the best, I think, since the probability of just your left side quantum tunneling through the wall is greater than the probability of all of you tunneling through.)
    Conserve energy. Commute with the Hamiltonian.

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    Grey has added to what I said in post 20. It will be clear that those finite non zero probabilities are not testable in human timescales. So do these rare events ever happen or is there another principle limiting the tunneling? Extending my sublimation analogy, the escaping atoms take energy from their environment including their neighbours. So that implies a scale limit to the probability of a single atom jumping off. Maybe in tunneling there is also a scaling factor from the remaining energy after a tunneling event. What i am getting at is that there is an energy implication that excludes any belief implication in atom behaviour. If you interpret belief as an information manifestation, our model does not allow that information to coordinate quantum events. Or to put it another way we cannot by belief alter those probabilities in order to walk through walls.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by Grey View Post
    In principle, quantum tunneling can work with collections of particles, and composite barriers. So technically, there is a nonzero probability that you could appear on the other side of the wall without making a hole. But if you work out rough probabilities of things like that happening, you'll find that it's not something likely to happen in many orders of magnitude more than the lifetime of the universe. (Which is for the best, I think, since the probability of just your left side quantum tunneling through the wall is greater than the probability of all of you tunneling through.)
    To be honest I think I have definitely stretched a point with this. Having re-read the article it does not mention walking through walls !

    The quantum eraser experiments, according to the author, show us that cause and effect is an illusion. Particles are following a narrative, based on the last occasion they were observed. In the experiments particles apparently change things in their past.

    He also says that just because macroscopic objects don't normally exhibit these effects does not negate the principle. That principle being that consciousness is involved in reifying ("making real") the path of an object.

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    Quote Originally Posted by kzb View Post
    That principle being that consciousness is involved in reifying ("making real") the path of an object.
    That is nonsense. It doesn't require consciousness.

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    Quote Originally Posted by Strange View Post
    That is nonsense. It doesn't require consciousness.
    Probably best for me to stop right here. Not right to hijack the thread, I'm out of my depth, and I now see the article is connected to a crowd funding campaign to prove we live in a virtual reality...

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