What does the 'space' inside an atom consist of?

[Kenneth Boon Faker]

Atoms make up all the material stuff around us, but most of an atom is empty space. The nucleus at the centre of an atom (99.95 percent of its mass) is orbited by tiny electrons (only 0.05 percent or less of the overall atomic mass). And as you've probably heard, an analogy is to think of the atomic nucleus as the size of a gnat inside the spacious Notre-Dame Cathedral (representing the size of the entire atom).

My question is, what does the empty space consist of?

I assume it can't be absolutely nothing, otherwise everything would collapse into a chaotic muddle of random energy. And it must be some form of energy - perhaps binding laws or information which keep the electrons in place around the nucleus?

Many thanks
Kenny

 

[phinds]

My question is, what does the empty space consist of?

"space" isn't a thing, it's just geometry. There is an electron probability cloud (not an "orbit") but there doesn't need to be anything else.

I assume it can't be absolutely nothing, otherwise everything would collapse into a chaotic muddle of random energy.

No idea why you believe that.

And it must be some form of energy - perhaps binding laws or information which keep the electrons in place around the nucleus?

Many thanks
Kenny

 

[Nugatory]

And as you've probably heard, an analogy is to think of the atomic nucleus as the size of a gnat inside the spacious Notre-Dame Cathedral (representing the size of the entire atom).

That's an analogy, and like all analogies there's only so far that you can push it before it breaks.

The basic problem is that although we call them "particles" for historical reasons, subatomic particles don't act anything like what that word suggests. A gnat can fly around inside the cathedral, and at any given moment it will occupy some small but specific volume of that space and everywhere else will be not occupied by the gnat. That's not how it works with an electron or other quantum particle; the entire picture of the particle as a little thing moving around in the space inside the atom is completely bogus.

 

[Drakkith]

My question is, what does the empty space consist of?

I assume it can't be absolutely nothing, otherwise everything would collapse into a chaotic muddle of random energy. And it must be some form of energy - perhaps binding laws or information which keep the electrons in place around the nucleus?

Why would it need to be made up of anything? If I have two charged particles an inch apart, does the space between them need to be filled with anything in order for each particle to feel a force from the other?

 

[PeterDonis]

I assume it can't be absolutely nothing, otherwise everything would collapse into a chaotic muddle of random energy.

Why do you think this?

 

[HAYAO]

I am sorry if I am terribly misunderstanding the OP's question, but do you mean "vacuum" when you say "empty space"?
You know vacuum exist, right? So there certainly can exist a "complete nothingness", right?

 

[A. Neumaier]

What does the 'space' inside an atom consist of?

The view that an atom mostly consist of empty space stems from the old times when Bohr's atomic model (as a miniature planetary system in which electrons surround the nucleus) was the best picture of what an atom is like.
But there are no electron particles moving around an atom. One cannot view the electrons as little balls moving inside a molecule and somehow avoiding falling into a nucleus. Such a configuration would be unstable. The nuclei would attract little charged balls until they fall into them.
But it is very well understood why atoms are stable - the ground state is a delocalized stationary state of the electrons in an atom, a state living indefinitely (unless the nucleus decays). In terms of quantum field theory, the space is filled by the electron field. The resulting electron density can be calculated by quantum mechanics. Indeed, this is one of the outputs chemists are interested in when they use quantum chemistry packages like GAMESS.

(Quoted from my article Does an atom mostly consist of empty space? from my theoretical physics FAQ, where more details can be found.)

 

[Kenneth Boon Faker]

do you mean "vacuum" when you say "empty space"?
You know vacuum exist, right? So there certainly can exist a "complete nothingness", right?

A vacuum isn't absolutely nothing. It has properties. This is something.

Why would it need to be made up of anything? If I have two charged particles an inch apart, does the space between them need to be filled with anything in order for each particle to feel a force from the other?

You're talking about a "force", which isn't nothing. A force is energy.

Me: "I assume it can't be absolutely nothing, otherwise everything would collapse into a chaotic muddle of random energy."

Why do you think this?

Well you can't have 'absolutely nothing' inside a physical system. It doesn't make any sense. There must be something, even if it's information, law, or properties. These are far from 'nothing'. Even though they are not physical in the classic sense, they are what give physical entities form in the first place.

(Quoted from my article Does an atom mostly consist of empty space? from my theoretical physics FAQ, where more details can be found.)

I think the most satisfying answer comes from this article. It reads, “There is no empty space around a nucleus .. The space is filled by an electron _field_ around the nucleus which neutralizes its charge and fills the space defining the atom size.”

 

[PeterDonis]

you can't have 'absolutely nothing' inside a physical system. It doesn't make any sense. There must be something, even if it's information, law, or properties. These are far from 'nothing'. Even though they are not physical in the classic sense, they are what give physical entities form in the first place.

This is all just personal opinion. "Absolutely nothing" is vague ordinary language. So are the other terms you are throwing around.

I think the most satisfying answer comes from this article. It reads, “There is no empty space around a nucleus .. The space is filled by an electron _field_ around the nucleus which neutralizes its charge and fills the space defining the atom size.”

"Empty space" as the term is used in this article does not mean "absolutely nothing" in the sense you appear to be using that term.

 

[Kenneth Boon Faker]

"Empty space" as the term is used in this article does not mean "absolutely nothing" in the sense you appear to be using that term.

Exactly. I'm satisfied with this answer because the author isn't implying that absolutely nothing exists inside the atom.

This is all just personal opinion. "Absolutely nothing" is vague ordinary language. So are the other terms you are throwing around.

Not at all. Law and information are an intrinsic part of the fabric of all physical systems. It is what patterns and bonds particles, atoms and molecules to give form to everything that we see around us. If you think it's personal opinion, then you just need a shift in your thinking to understand the truth of it.

 

[PeterDonis]

Law and information are an intrinsic part of the fabric of all physical systems.

No, they are an intrinsic part of our models of all physical systems. Models are not the same as the things being modeled.

 

[PeterDonis]

If you think it's personal opinion, then you just need a shift in your thinking to understand the truth of it.

Sorry, but that doesn't change the fact that it's personal opinion as far as discussion at PF is concerned, and therefore is out of bounds here.

 

[weirdoguy]

If you think it's personal opinion, then you just need a shift in your thinking to understand the truth of it.

Says layman to physicist...

A force is energy.

Since when?

 

[Kenneth Boon Faker]

Since when?

To be more specific, pure energy exists out of force carriers like particles, (e.g. photons and gluons)

Says layman to physicist...

But physicists often get too tied up with physics, in the sense that they believe that anything non-physical cannot exist. What about natural law, information and consciousness?

No, they are an intrinsic part of our models of all physical systems. Models are not the same as the things being modeled.

That is very true. Indeed, the assumption that "reality consists of only physical things", is ultimately a subjective model, which might not actually be aligned with reality. Is there a deeper level of reality from which all physical things arise?

 

[PeterDonis]

What about natural law, information and consciousness?

"Natural law" is part of our models, not the things being modeled.

Information and consciousness are physical things; at least, that's what practically all physicists believe. Physicists have precise definitions of "information" (the most common one is the inverse of Shannon entropy). We don't (yet) have a comprehensive theory of how consciousness is produced by physical brains, but much progress has been made in that direction, though not by physicists--by neuroscientists and cognitive scientists. But everything they are doing is based on the belief that consciousness is a physical thing; we just have to figure out the specifics.

 

[PeterDonis]

Is there a deeper level of reality from which all physical things arise?

This is a confused question. If there were such a "deeper reality", the response of physicists would be that it was also a physical thing.

 

[Drakkith]

You're talking about a "force", which isn't nothing. A force is energy.

No, force and energy are not the same thing, nor does one make up the other.

To be more specific, pure energy exists out of force carriers like particles, (e.g. photons and gluons)

There is no such thing as 'pure energy'.

 

[HAYAO]

A vacuum isn't absolutely nothing. It has properties. This is something.

Your terminology is going everywhere. Please use the standard terms or define it well (under certain physical model) and stop playing around with words.

The "vacuum" I said above is the word I use for laymen to mean "absolute nothingness", and depending on the specific physical model we use, vacuum can surely be defined as "absolute nothingness". Indeed we have tons of physical models that treats vacuum as absolute nothingness.

Vacuum is not "absolute nothingness" from the perspective of pQFT, simply because we model it that way (and it works for several situation with high precision). Did you mean vacuum in this sense? What exactly are you asking for?

 

[bhobba]

You're talking about a "force", which isn't nothing. A force is energy.

Please look into something called Noethers Theorem to find out what energy really is:
http://math.ucr.edu/home/baez/noether.html

Newtons first law follows from the second which is a definition - namely of force. The content is really in the third law which is experimentally testable - the others are problematical. Can that be physics? I shall leave you to think about that one a bit because it really is off topic - do a new thread if what's really going on doesn't gel - its may not because it is a bit subtle, but we do like people to try and figure things out first before posting.

Thanks
Bill

 

[Derek P]

Please look into something called Noethers Theorem to find out what energy really is:
http://math.ucr.edu/home/baez/noether.html

Newtons first law follows from the second which is a definition - namely of force. The content is really in the third law which is experimentally testable - the others are problematical. Can that be physics? I shall leave you to think about that one a bit because it really is off topic - do a new thread if what's really going on doesn't gel - its may not because it is a bit subtle, but we do like people to try and figure things out first before posting.

Thanks
Bill

Well said. I have read somewhere, though I can't remember where, that Newton himself was unhappy with the idea of an entity called a force and thought it was metaphysical. Perhaps these days we would say it exists in the formalism but is not ontic :) Bohr was not the first to burden a physics theory with existential (or do I mean ontological?) philosophy!

 

[A. Neumaier]

Newton himself was unhappy with the idea of an entity called a force

Only with force at a distance!

 

[Derek P]

To be more specific, pure energy exists out of force carriers like particles, (e.g. photons and gluons).

That's vague and incorrect in many ways but I can guess what you're referring to. As a matter of fact although energy seems to drive processes, most are driven by entropy rather than energy. So don't get carried away with the idea of pure energy. The particle picture, too is an interpretation of field theory and it is by no means clear whether fields are part-and-parcel of a higher form of space or whether they simply permeate the familiar three dimensional manifold.

Is there a deeper level of reality from which all physical things arise?

If there are deeper levels then they are outside the realm of physics. To assert otherwise (pace @PeterDonis) is to impose one's own philosophical bias on the subject. There is a good reason why such speculation is called meta-physics. It goes beyond physics.

 

[bhobba]

Well said. I have read somewhere, though I can't remember where, that Newton himself was unhappy with the idea of an entity called a force and thought it was metaphysical. Perhaps these days we would say it exists in the formalism but is not ontic :) Bohr was not the first to burden a physics theory with existential (or do I mean ontological?) philosophy!

Its not metaphysical - it does make a statement about nature - but not of the usual type.

Think a bit and start a thread if what's really going on isn't clear. Don't worry if the answer doesn't become clear - I never figured it out until John Baez explained it - then you say of course.

Thanks
Bill

 

[PeterDonis]

The OP question has been answered and the thread is degenerating into personal speculation. Thread closed.