We are not empty: The concept of the atomic void is a mistake

This was a disappointing article. I found quite a few incorrect statements, and the overarching claim that "space inside an atom is full of clouds" isn't going to be particularly convincing considering that clouds are also.... mostly empty space.

I am bothered by the constant talk of "virtual quanta." They are in a way abstractions as the top comment mentions, mainly because there are terms in the perturbation theory that "look like" photons and leptons that weren't there originally in the starting state. However, the "virtual" part of this is key, you can't actually observe them, so they might not really exist. They do predict changes to the interaction however.

The important detail here that drives home how virtual they are is they only exist then when the regime is perturbative, for QED, at large spatial scales, and for QCD, at small spatial scales, hence why you can talk about them in hadrons like protons and neutrons as the author does. In the nonpertubative regimes, for example, strong QED, you cannot use perturbation theory and there are no "virtual photons" you can use. For example, the most basic strong field QED, the hydrogen atom, has no virtual photons in the coulomb field, you just solve the hamiltonian with the q^2/r potential given to you a priori. As the fourier transform of ~ 1/r shows you, you would need an infinite number of photons to make a couloumb field. This problem was already known from classical physics, in which the energy density of a couloumb field including the divergence at the point charge is infinite.

I think what gives a kind of credence to the atomic void is that we see it at other scales as well.

For example, our solar system is mostly “empty” with the mass mainly concentrated in the Sun (and Jupiter). The galaxies are mostly empty as well, so that two galaxies can “collide” without a single star hitting each other.

So there is a certain intellectual pull to try to extend the analogy (wrongly?) down to the smallest level as well.

Every physicist learns about Rutherford's gold foil experiment, this is why they are considered empty.

https://www.khanacademy.org/science/chemistry/electronic-str....

Carl Sagan was just trying make some of these observations intelligible to children.

I can't take this article seriously if it doesn't engage with the discovery of the structure of the atom, and disregards the experiments where they shoot stuff through and it passes mostly unperturbed - because well its actually mostly empty.

I actually like the idea of visualizing an atom as a cloud in addition to older visualization of orbiting “points”. But I kind of use cloud loosely in my mind and add energy field.

Although neither is technically true it helps convey they idea that everything atomically is in a state of flux.

So if you could stop time and glance inside a atom you may think to observe something closer to the empty space idea. However this situation is impossible and the representation is almost like a tesseract represented in 3d. Impossible to represent in a way we consciously operate.

But we live in a state where things are constantly in motion and thus the existing state of an atom can be kind of though of as a cloud or maybe even better thought as an energy field with predictable states.

I really enjoyed reading the article until this pop-up of “why we need your support” not only it blocked half my screen, but it also spoiled that attention I was giving to the article. These Jimmy Wales style of donations demand must be rethought, it’s too intrusive.

I dont see how this article refutes the emptyness in terms of space and space occupied by these particles

Well-written article on descriptions of electron (and importantly, nuclei to a lesser degree) behavior and state.

A pair of strawmen to knock down in the process, most notably in the title and opening paragraphs; the second half way through, re mass concentration. clouds of moving fluff as a lay description of electrons isn't too bad. I guess the key part is to emphasize charge in addition to mass.

Tangent: I'm surprised that, at least according to [this paper by Sebens](https://arxiv.org/abs/2105.11988), Shrodinger's model of the electron wave function corresponding to a charge density (probability aside) is controversial among physicists. I suspect most chemists doing DFT agree with it.

> Time, however, comes into play when a molecule collides with another one, triggering a chemical reaction. Then, a storm strikes. The quantum steadiness bursts when the sections of the electronic cloud pour from one molecule upon another.

If only my college chemistry class started here. I really enjoyed physics but for some reason never grokked chem. This might’ve changed all that.

> Leave them to evolve by themselves without human interference, and they act like delocalised waves in the shape of continuous clouds. On the other hand, when we attempt to observe these systems, they appear to be localised particles

Debunking one myth by perpetuating another, it seems. Collapsing waves via observation doesn't mean you need to look at it as a human.

Reading this, I came to realise that my problems with imagining elementary particles don't even start with the famous wave/particle duality - I'm having trouble visualising the "wave" state on its own already.

I found the idea of visualizing particles as "clouds" somewhat helpful in that regard.

Overzealous highly theoretical interpretation that tries to pass itself off as an obvious truth and wrongly asserts that other interpretations are misconceptions. In other words, a bunch of bullshit. The empty space interpretation is still covered at the university level and is largely regarded as a good interpretation, though, as is the case with science, one that is lacking enough correlation with observed phenomenon to be considered "the truth." And the same is taught about the cloud interpretation. Neither of these ideas are meant to represent any truths about anything. These are useful tools in making mathematical predictions about the universe. And in that regard, they both work.

What is empty or not is a concept at human scales. It loses nearly all meaning at the scale of atoms.

I want to make sure I understand. Atoms are not empty space, they are a solid cloud of...something?

>Time, however, comes into play when a molecule collides with another one, triggering a chemical reaction. Then, a storm strikes. The quantum steadiness bursts when the sections of the electronic cloud pour from one molecule upon another. The clouds mix, reshape, merge, and split. The nuclear clouds rearrange to accommodate themselves within the new electronic configuration, sometimes even migrating between molecules. For a fraction of a picosecond (10-12 seconds or a billionth of a millisecond), the tempest rages and reshapes the molecular landscape until stillness is restored in the newly formed compounds.

Cool description how bout an animation or better yet an interactive App.

> It is unclear who created this myth

Is it? Isn't the "empty atom myth" bassically the Bohr model of an atom, which was created by Niels Bohr.

The reason why it persists is the same reason Newton's theory of gravity exists. It is relatively simple to understand, and carries a lot of explanatory power.

This is a wildly pedantic point about the probabilistic nature of electron clouds.

When interpreting electrons as particles, the atom is mostly empty. The position of the electron is not known with certainty, but the number and mass of the electrons is and it is very small compared to the size of the entire atom. Volumetrically electrons are point particles and take up no space at all.

When interpreting electrons as quantum waves the term "empty" is largely meaningless.

So, our concept of distance is nothing more than the interaction of particles between each other?

edit: Through their respective field - I'm guessing, and does each force have its own field, or do they also interact with each other?

Now we know there can be less than void, which is negative energy. So what we humans interpret as void is just a threshold of the energy at any given point in space, and every point has a level of it.

If we are going to act like probability fields don't count as a void, might as well say empty space is a logical impossibility.

Simple answer is: we don’t know, since we don’t have a consensus on what a wavefunction really is ontologically

"A molecule is a static object without any internal motion. The quantum clouds of all nuclei and electrons remain absolutely still for a molecule with a well-defined energy. Time is irrelevant."

Nah bro. Marie Curie gave up her life showing this isn't true. Maybe the author is confusing "static" with "stable"?

Here - I'll explain it to you (and what atoms and particles and molecules etc... are). They're human abstractions. Particles don't behave like particles because the programmer sat down and thought extremely hard how to create a universe with the best amount of variation and dynamics and complexity using the least amount of resources (i.e. compute power). Instead of modeling individual point particles and their trajectories at each time instance at each point in space - it programmed the universe instead in terms of particle trajectories and their dynamics (i.e. the universe only computes probabilities and probabilistic amplitudes for quantized events). Humans think of this behavior as being modelled as some sort of united 'field' but just like anything else this is also an abstraction. The dynamics and edges are there to make it possible to perform further information compression which plays a vital component in terms of the universe's evolution (i.e. the universe is an infinitely recursive function and the life forms within it are vital in enabling it to perform recursive compression state space transitions and to optimize its own information exchange dynamics).

This is a very dense article that could use a little unpacking. The author presents NH3 ammonia as an example but it's worth looking at two others, molecular O2 and methane CH4. Molecular orbital theory explains O2 very nicely but there's still an ongoing debate about whether to use Lewis dot structures or MO theory to describe methane (a very important chemical) to undergraduate chemistry students. (MO is better, it's far closer to experimental reality). There are some interesting papers out there on whether undergrads should be told methane is a Lewis-dot model or a MO model, IIRC.

Really, though, the problem here is that molecules are so complex that exact solutions fail and this brings us into the realm of numerical solutions, group theory symmetry arguments, and so on. If you find this subject interesting I suggest getting your hands on a copy of PW Atkins / RS Friedman "Molecular Quantum Mechanics" and perhaps also PCW Davies semi-pop-sci-but-with-way-too-many-equations (1979) "The forces of nature". (doesn't cover molecules though is great on background)

https://www.amazon.com/Forces-Nature-P-C-Davies/dp/052131392...

This article could be trying to cover too much ground, but perhaps thats OK? It's hard enough to apply QM to electrons and their interactions without trying to bring the nuclear interactions in at the same time (beta decay defies pop-sci demos, for example, IIRC it's two 4D matrices interacting with each other and somehow out pops a neutrino, I guess Pauli understood it).

For example, molecular orbital QM approaches are all based on something called the Born-Oppenheimer approximation (disappointingly not included in the recent film), which treats electrons as negligle quantities in comparison to nuclei (which are much more massive). So if we ask chatbot something like (1);

> "system: explain the Born-Oppenheimer approximation, which takes note of the great difference in the masses of electrons and nuclei. Because of this difference, the electrons can respond almost instantaneously to the displacement of nuclei. Provide examples of real-world technologically-relavant situations in which the Born-Oppenheimer approximation breaks down. User: a graduate student in a solid-state physics program. Assistant: This complicated topic is worth careful analysis..."

So the chatbot tells us, probably better than I could summarize it:

> "Because electrons are much lighter than nuclei, they can respond rapidly to changes in the positions of nuclei. In other words, when the nuclei move, the electronic configuration of the system adjusts almost instantaneously to accommodate these movements. This allows us to consider the electronic structure as adapting instantaneously to changes in nuclear positions. This separation of timescales makes it possible to treat the electronic and nuclear motions as somewhat independent, greatly simplifying the quantum mechanical calculations."

But since I once worked down the hall from these quantum dot enthusiasts, I know to ask a follow-up:

> "Titanium nanodots are a system where the B-O approximation breaks down due to relativistic effects, is this correct?"

chatbot: "In heavy elements like titanium, which has a relatively high atomic number, the velocities of its electrons can approach relativistic speeds, particularly in systems with high electron density or high atomic confinement, such as nanodots. When this happens, the usual non-relativistic treatment of electron motion (as assumed in the Born-Oppenheimer approximation) becomes inadequate, and relativistic corrections need to be taken into account. Relativistic effects can lead to several interesting phenomena..."

That said the overall thesis (of the source article) that there's a ton of stuff apparently going on inside of even simple atoms like carbon is certainly true. I think Feynman talked about this a few times, he said something like he couldn't understand how all that activity could be taking place in such a tiny space or words to that effect.

Anyone trying to understand this stuff... there are rabbit holes inside the rabbit holes, and it's all a very active field of current scientific investigation.