We are not in the Eighth dimension, we are over New Jersey

August 30, 2023 3:59 PM

My criticism of the empty atom picture isn’t meant to shame people’s previous attempts to describe atoms and molecules to the public. On the contrary, I applaud their effort in this challenging enterprise. Our common language, intuitions and even basic reasoning processes are not adapted to face quantum theory, this alien world of strangeness surrounded by quirky landscapes we mostly cannot make sense of. And there is so much we do not understand. from We are not empty by Mario Barbatti
posted by chavenet (40 comments total)

I'm sure that in the miserable annals of the Earth this new insight will be duly noted.
posted by Meatbomb at 4:22 PM on August 30, 2023 [10 favorites]

Beautifully written, thank you for sharing this.
posted by rebent at 4:37 PM on August 30, 2023 [1 favorite]

Mario Barbatti wrote the article. Pam Weintraub edited it. Great article. It gave me a better way to think about atomic structure.
posted by njohnson23 at 6:16 PM on August 30, 2023 [2 favorites]

Maximum kudos for the post title. Now off to read the article ...
posted by Illusory contour at 6:25 PM on August 30, 2023 [5 favorites]

The man's been through solid matter, for crying out loud. Who knows what's happened to his brain? Maybe it's scrambled his molecules!
posted by rmd1023 at 7:03 PM on August 30, 2023 [3 favorites]

A good read. Thank you. I think spin gets a bit of a short shrift , considering its role in magnetism. But Hilbert spin state math taxes my tiny brain.
posted by mrzz at 7:09 PM on August 30, 2023 [1 favorite]

We are not empty, yet neutrinos can pass right through us without any interaction. Physics is so weird.
posted by Grumpy old geek at 7:31 PM on August 30, 2023 [3 favorites]

This is me joking around - not sure if allowed - but the 4th grader in me always liked the bra ket notation. I wonder if Dirac had that sense of humor?
posted by mrzz at 7:42 PM on August 30, 2023 [1 favorite]

This a very good read, and there a couple of lines I really, really like. Electrons are the orbitals really gets me, and it's something I really struggle to accept even though I sort of understand the layperson's idea of the underlying theory. Our ultimate goal is to tell stories about our Universe also really resonates with me. I think science works better much of the time, or at least translates better to nonscientists or even other scientists who are not experts in a particular field, when scientists understand they are trying to tell stories about what they observe.
posted by mollweide at 8:01 PM on August 30, 2023 [3 favorites]

This is me joking around - not sure if allowed - but the 4th grader in me always liked the bra ket notation. I wonder if Dirac had that sense of humor?

Not obvious to me which usage of the word came first, actually...
posted by kickingtheground at 8:34 PM on August 30, 2023 [1 favorite]

QCD is a surprisingly readable book. Not that I could make predictions off Feynmans insights - but wave theory really comes through.
posted by mrzz at 8:50 PM on August 30, 2023 [2 favorites]

This was the first thing I've ever read about quantum mechanics that helped me to understand it.

I usually find that articles trying to explain counter-intuitive phenomena start by saying, "Here's how it's usually presented, but that's all wrong! Here's how it actually works...". What they focus on is what people are misconceiving which is easy to explain. This article focuses on how people misconceive the quantum realm and works effectively to describe in plain language how to overcome the gap between popular understanding and a more sophisticated grasp of reality.

It is a brilliant article.
posted by Ickster at 9:28 PM on August 30, 2023 [2 favorites]

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. Quantum theory does not predict vibrating nuclei or orbiting and spinning electrons; those dynamic features are classical analogues to intrinsic quantum properties. Angular momentum, for instance, which in classical physics quantifies rotational speed, manifests as blobs in the wave function. The more numerous the blobs, the bigger the angular momentum, even though nothing rotates.

I don’t know how to reconcile "time is irrelevant" with the consistency in time of the rates of decay of particular radioactive nuclei. In other words, how is it that all collections of U 238 seem to display half-lives of ~4.5 billion years, while U 235 always shows a half-life of a couple hundred thousand if nuclei in atoms are utterly static and have no internal clocks?

I suppose you could say these decay events are completely random, not caused by any prior event, and therefore not in a timeline, but that they are collectively constrained to conform to a particular half-life seems to contradict that.
posted by jamjam at 11:54 PM on August 30, 2023 [1 favorite]

Mario Barbatti wrote the article. Pam Weintraub edited it.

[facepalm emoji]. Sorry about that.

Here are links to more about Mario Barbatti
posted by chavenet at 1:58 AM on August 31, 2023

I don’t know how to reconcile "time is irrelevant" with the consistency in time of the rates of decay of particular radioactive nuclei.

I believe he means time is irrelevant within the atom itself. The equations which define the phase space are fixed and known. There is no 'motion' within the atom itself but simply wave functions.

However, the atom interacts with the universe, even in a vacuum there are vacuum fluctuations and this may cause alterations in the phase space. There is always a non-zero probability of various configurations including the one corresponding to radioactive decay. The probability is a direct result of the shape of that wave function which is the same for every U238. The term 'half-life' is just a name for the collective probability deduced for this type of decay.

In other words, 'time' shows up because the timeless atom exists in a Universe. And Time is an aspect of Spacetime which is the theater for where all these events occur. Time and Space are what we use to quantify things that are not-this-one-atom.
posted by vacapinta at 2:25 AM on August 31, 2023 [2 favorites]

I don’t know how to reconcile "time is irrelevant" with the consistency in time of the rates of decay of particular radioactive nuclei.

If you think you understand quantum mechanics, you don't understand quantum mechanics.

-- Richard P. Feynman
posted by DreamerFi at 4:13 AM on August 31, 2023 [2 favorites]

That explains everything. Or does this?
posted by y2karl at 6:31 AM on August 31, 2023 [1 favorite]

I don’t know how to reconcile "time is irrelevant" with the consistency in time of the rates of decay of particular radioactive nuclei.

I am not knowledgeable w.r.t. physics, but I would like to offer a perspective complementary to vacapinta's above.

Imagine rolling a bucketful of dice. After your roll, you remove any dice that rolled a six. Gather the dice, roll them again, and remove the dice showing six again. Repeat the process of rolling and removing sixes over and over.

If your dice collection (and bucket) are large enough (certainly the quadrillions or quintillions of atoms in a radioactive sample would be enough), there will be very little variation in how long it takes for half of the dice to be eliminated by this repeated process. This is despite their being no memory inside any particular die to keep track of how many die rolls that die has "survived".
posted by a faded photo of their beloved at 6:32 AM on August 31, 2023 [7 favorites]

I suppose you could say these decay events are completely random, not caused by any prior event, and therefore not in a timeline, but that they are collectively constrained to conform to a particular half-life seems to contradict that.

They just occur with different probabilities in different isotopes. Even a particle with a very long half-life could decay almost immediately, it's a purely chance event. When you have a chunk of an isotope it averages out to decaying at some rate, but that's because you're summing many, many independent random events.
posted by BungaDunga at 6:42 AM on August 31, 2023 [1 favorite]

And all the uranium on earth could just decay at once tomorrow morning. Possible, improbable. I used to have fun at university house parties telling people that nothing really ever touches, it's just the electrons on the outside pushing against each other. If you could touch, you would melt/weld together and if it wasn't for that electron repulsion we'd all start just sinking through the ground and bouncing up and down through the earth due to gravity. I'm fun at parties.... :)

I've only made it half way through the article, but the idea that the atomic wave is static and timeless in some way is bogus. The things that create the strong force that holds the nucleus together are also bound by the speed of light and distance. Therefore there is time, therefore there is fluxuation and non-static. You can't get the Platonic solid if bits and pieces inside have to travel through space-time. There will always be fluctuation even on the local scale. Just not enough to be statistically significant. Time is hard to remove.
posted by zengargoyle at 8:53 AM on August 31, 2023 [1 favorite]

It gave me a better way to think about atomic structure.

The way I like to think about atomic structure is that every part of the universe is unique, and that if an observer believes that some feature of reality is exactly the same as some other feature spatially and/or temporally separated from it, that's because that observer has made a deliberate choice to ignore some amount of context for the sake of convenience.

I object to the idea that reality "is made of" particles or empty space or whatever because I can find no justification for thinking of reality as something that is made to begin with. We make particles, waves, fields and so forth, to give us a vocabulary with which to describe reality to ourselves and each other. Reality itself just is, regardless of how any of us chooses to think about it, and insisting that reality has a "true nature" best described this way or that way or the other way - material, spiritual, unitary, atomistic, many-worlds, conscious, divine, unknowable, whatever - is nothing more than hubris. In any conflict between description and reality, reality wins.

I'm quite glad that heavily compressed summaries of reality can be composed in the language of patterns and that doing so confers such useful amounts of predictive power, because I think life would be much less fun if they couldn't.

Starting from there, I am completely comfortable with the idea that the "elementary" particles from which "material" reality "is made" interact in ways for which the only satisfactory description is statistical. We find these things and their interactions when we go looking for them, and we find characteristic patterns of interaction and can describe these in enough detail to do some excellent engineering with the results, and I'm happy with that.

But uniqueness and randomness go hand in hand, randomness being only and exactly information for which no précis is available. "Principled" objections to the lawlessness of it - "God does not play dice" and so on - are just hubris in disguise. I have no expectation that a physical theory suitable for use by Laplace's Demon should exist even in principle, causality itself being no more than another explanatory pattern that we have made up to suit our own purposes.

According to quantum theory, the building blocks of matter – like electrons, nuclei and the molecules they form – can be portrayed either as waves or particles. 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, something like bullets in the classical realm. But accepting the quantum predictions that nuclei and electrons fill space as continuous clouds has a daring conceptual price: it implies that these particles do not vibrate, spin or orbit. They inhabit a motionless microcosmos where time only occasionally plays a role.

I like to think of those delocalised waves in the shape of continuous clouds as summarizing our best understanding of what we think can happen in and to the systems they describe, on the basis of how we've seen systems like that behave before. What actually does happen remains strictly unpredictable because no part of reality is exactly like any other, but we've seen this kind of thing happen enough times to be certain enough for practical purposes that what happens next will be that kind of thing as well.

So it's not necessarily the system that those wave functions describe within which time only occasionally plays a role; it's the wave functions themselves. And we don't and can't have a better predictor than functions of that sort for what's really happening or about to happen, because when it comes right down to it the regularities that are the only thing we could possibly base such a predictor on are themselves only statistical. Every piece of reality is unique.
posted by flabdablet at 9:12 AM on August 31, 2023 [3 favorites]

What ARE electronic orbitals? (Three Twentysix, Youtube/Piped, 21m33s)
posted by flabdablet at 9:41 AM on August 31, 2023 [2 favorites]

What's that watermelon doing there?
posted by Naberius at 9:58 AM on August 31, 2023 [4 favorites]

Meh, third semester university physics. Not sure I want to read the rest of the article, sounds like a lot of "duh" we knew that in the 80's didn't you pay attention in science class? Oh and 3d waves don't cancel on universe scale because they would never even make it to the edge in the expanding universe to be reflected. You need a wave reflective boundry for the reflection to occur. Not happening on any possible human timescale to observe.
posted by zengargoyle at 10:29 AM on August 31, 2023 [1 favorite]

Oh, and the whole bead thing was a bit of bogus. A bit of theatrical let's flip things around that is fucking bullshit. The standing waves in the tube are sound waves and compressed or expanded gas (air as it were). The little balls go up because they are pushed from both sides, do the same thing and punch holes in the pipe and pump say propane through it and set it alight and you will find the opposite pattern, the high pressure points are the high flame points. Fucking failing first/second semester physics there or just lying to try and make a point.
posted by zengargoyle at 10:48 AM on August 31, 2023 [1 favorite]

God does play dice.
And cheats, for that matter...
posted by y2karl at 3:13 PM on August 31, 2023 [1 favorite]

I'll tell you later.
posted by Meatbomb at 3:39 PM on August 31, 2023 [2 favorites]

I really enjoyed this article, I'm just having trouble squaring it with my understanding of Rutherford's gold foil experiment. Without a heavy point mass, what is the alpha particle being deflected by? What am I missing?
posted by Hactar at 6:07 PM on August 31, 2023 [1 favorite]

I don't think you're missing anything so much as adding a quality to your mental model of alpha particles and nuclei that there's actually no experiential justification for: the quality of object permanence that familiar, identifiable macroscopic objects have.

Billiards balls and BB pellets are nice polite objects that stay where they're put and remain identifiable as themselves all the way through any trajectories they describe. The structures identifiable on the fine scales best modelled by quantum theory are not.

One useful way to think of familiar, polite object permanence is as an emergent quality of macroscopic structures, an emergence that proceeds from the statistical regularities that are only to be expected given their utterly titanic scale compared to that of their quantum substructures.

Those statistical regularities make it reasonable to ignore almost all substructure behaviour when modelling the behaviour of macroscopic objects, allowing us to have really good predictive success using only intuition augmented by the relatively straightforward mathematics of Newtonian mechanics.

Once we're working down at the scales where alpha particles and electrons are the kinds of objects in the models, though, we can't rely on half of our metaphorical collection of fair coins turning up heads and need instead to deal with the consequences of not only not being able to predict which way any given coin is going to land but being unable to justify claiming with certainty that any given coin is the one we just flipped.

We can predict, successfully, that if you poke a structure over here in some precisely describable way then you'll observe behaviour over there with some specific degree of likelihood. Exactly what goes on between stimulus and observation remains unknowable because the only structural description of what even exists on these scales is statistical.

If all of the above reads like handwaving, that would be because that's exactly what it is. But the same applies to any "explanation" of physical theory that is not, in fact, physical theory.
posted by flabdablet at 9:03 PM on August 31, 2023 [2 favorites]

When I was a teen I sometimes went to 1/4 mile drag-strips, all these beautiful unreal fast dangerous as fuck cars, all of the people who put it all together -- I'd wander around the pit area, these unreal competent mechanics completely rebuilding new motors in between races, they seemed casual but they were in fact serious as polio.

The races are great, esp top fuel and funny car races, get close to the start line and here they are, doing these unreal burnouts, to warm their tires -- the beauty of it, the unreal noise, fire flaring out of the exhaust. But really, most all of the races were cool, a kick to be there.

I've rebuilt a motor, and worked with friends on their cars, I've got a shitload of tools and I can use them, to a limited degree; putting that motor together is a pretty cool thing, I've changed out clutches, rebuilt a zillion brakes in various vehicles I've owned, changed out the rear end on a pickup truck on the coldest day of winter here in ATX, put the rear end on and then changed out the brakes that were on the old rear end. I don't know that I'd call that fun, but it was fun.

But when I was in the pit around those people who can do anything and do it well and do it fast, that showed me clearly that I am not a heavy hitter.

~~~~~

When I come to Metafilter and into a thread like this one the feeling is familiar. I do what I can to understand physics, I find myself shaking my head over its complexities yet I do follow as far as I can. All of the heavy hitters here on MetaFilter, it's like watching those ppl who could and did rebuild top fuel motors in almost no time at all, and followed along by being there and watching close as I could.

It hurts like hell that I don't have the right head to follow Feynman but only so far. I read the article, I read what you've written, and while I can only understand only so far, I get a sense of it, I pay attention to you all, I read it deep as I'm able to grok it.

I'm really grateful that you all are here.

And I'm grateful that I'm here, gleaning what I'm able..

Which is to say: A great thread, OP, thank you for posting it here on The Blue.
posted by dancestoblue at 11:25 PM on August 31, 2023 [3 favorites]

Without a heavy point mass, what is the alpha particle being deflected by? What am I missing?

The way I read it, the nucleus' wavefunction is much much much more concentrated in the middle than the electrons are, so that's where the positive charge and mass mostly is.
posted by BungaDunga at 7:03 AM on September 1, 2023 [1 favorite]

Meh, third semester university physics.

Most folks don't go to college, much less major in physics.
posted by device55 at 6:06 PM on September 1, 2023 [3 favorites]

the nucleus' wavefunction is much much much more concentrated in the middle than the electrons are

This is a quality that nuclei share with brontosauruses.
posted by flabdablet at 6:44 AM on September 2, 2023 [1 favorite]

Most folks don't go to college, much less major in physics.

I knew this in high school. I went to university as a physics major and switched to computer science rather quickly, had one university physics lab.

I learned this around junior year of high school at like 15.

It is not something mysterious and unapproachable or hard. A teenager can manage it. It just might take a bit of time if you're actually interested. You don't have to go to college and major in physics. It might take a month or two, to get the foundation, after that (unless you're trying to write a paper or something) just a bit of keeping up enough to pontificate.

I never actually had real university physics and it wasn't my major... make of that what your will.
posted by zengargoyle at 7:36 AM on September 3, 2023 [1 favorite]

I learned this around junior year of high school at like 15.

I took non-AP highschool chemistry and physics; neither got into the modern understanding of electron orbitals. Physics spent most of its time trying to convince students of Gallilean relativity, and chemistry was mostly learning about how to calculate moles and such.

Probably AP Chem and/or AP Physics do, but I didn't do either of those, even though I took a bunch of other AP courses. This stuff isn't hard, exactly, but it's not common knowledge because only a fraction of people are exposed to it. It's not surprising that most people never got much beyond the Bohr model, not least because it's reinforced everywhere.
posted by BungaDunga at 10:08 AM on September 3, 2023 [1 favorite]

It is that strangest of physical phenomena, the Schrodinger's article, which simultaneously tells you something new and interesting, and yet something you learned back in grade school!
posted by mittens at 11:06 AM on September 3, 2023 [2 favorites]

I knew this in high school.

I learned this around junior year of high school at like 15.

It is not something mysterious and unapproachable or hard. A teenager can manage it. It just might take a bit of time if you're actually interested.

... make of that what your will.
posted by zengargoyle at 9:36 AM on September 3

You have no idea how lucky you are, that's what I make of it.

I was shoved into all of the dummies classes. Most of us in those classes were not dumb. Some of us were messing around with drugs, maybe most of us -- it's what was expected of us, drugs were cheap and plentiful. Almost every one of us came from homes without structure, families that were broken, under the gun in whatever way. None of us had anyone to make sure we weren't falling behind, no one in our homes and no one in the schools, who had already thrown us away.

I was working in the trades, had already had my first good fall -- 14 feet, head over heels, hit on the back of my head and shoulders, my body whipped around so hard it threw my shoes off. Dirt, not concrete, or I'd likely have died. Not soft dirt -- it was in December. I was 14. I already knew my future -- I was going to make a lot of money working construction, have a pickup truck, a Buick for my wife, a picket fence and a dog barking. I didn't notice how only a few men lasted long enough for that house note and Buick; my body was trashed by my early 30s.

I didn't see physics until I read about it, Carl Sagan, Cosmos. I've tried to piece it together but without being conversant in math you can only go so far. I love Feynman, I follow far as I can but hit the wall fast. I do want to know. I do what I can.

You are incredibly lucky.
posted by dancestoblue at 11:03 PM on September 3, 2023 [2 favorites]

Here we go again: The Mechanical Universe - YouTube.

Put aside your show or your book or whatever and watch some physics if you want. I watched the first half of this at 15 (the rest hadn't been made yet) and yes I was lucky to go to a summer program at a university and fill out the rest (the same university). I slept through high school AP physics, my teacher was scared of me for putting ijk with hats and writing greek things. You can right now if you want get like 80% of what I had as a poor assed fucked up family kid in the middle of the mountains in the middle of nowhere with ancient teachers and only one school. Got plenty of scars of myself.
posted by zengargoyle at 5:05 AM on September 4, 2023 [1 favorite]

Not sure I want to read the rest of the article, sounds like a lot of "duh" we knew that in the 80's didn't you pay attention in science class?

zengargoyle, I say this with the greatest respect because most of what I've seen from you has been thoughtful, insightful, helpful and generous: this seems to be a blind spot for you, one that I recognize from my own experience, and I hope you can make some use of what I've learned about trying to see around the edges of several very similar.

I have spent countless hours in a state of complete astonishment at how it is possible for people to live satisfactory lives without the grounding in basic mathematics, chemistry and physics that I acquired in my school years. All of these disciplines are built on fundamental insights that make navigating the world with confidence so much easier, and as I got older I used to experience enraging levels of frustration at watching people cause themselves so much trouble, over and over again, simply for the lack of them.

As I got older still, though, I became increasingly aware of how little effort I had personally put into studying any of that stuff. Rather, I had consumed it voraciously as a kid, partly because I had the opportunity to but mostly because I liked it, and I was a kid, and voracious consumption of learning that we like is what kids are built to do. And now that I'm of retirement age (early! Thanks, IT!) I'm much more inclined to see the relative amounts of difficulty that I and the people around me experience with the whole business of being alive as almost entirely a matter of luck.

Raising kids with far more extensive learning difficulties than I ever had has taught me that most people simply never see the levels effort that kids do put into trying to learn whatever it is that their seniors are trying to cram into their little heads. And because we're not in those little heads with them, we've basically got no idea what skills they are socking away in there that we have no clue about but they are going to be able to take full advantage of later on.

I guess what I'm trying to ease my way across these eggshells towards is that it's fine for people to come later in life to the lovely stuff that others of us have had a handle on for forty years, and dismissive snorts about their failure to do so earlier, or about materials designed to encourage them to do so now, come over as ungracious and frankly a little weird. I mean, there's stuff here that people who aren't you and me had been well across for years in the 1930s.

Do I deserve to have the shade of Einstein cock a sardonic eyebrow at me for not getting around to thinking about these things until sixty years after he did and then doing a much more half-assed job of doing so? No. Einstein's 6502 assembly language game is weak.

Thanks for the links to The Mechanical Universe. There are a couple of people I know whom those are going to suit perfectly. It's good to know where to find cool stuff that I think some of my friends will like, and the fact that not all of us are going to like the same cool stuff doesn't make any of it useless.
posted by flabdablet at 9:59 PM on September 4, 2023 [2 favorites]

I'm telling people that they can if they want to. There are some people in this thread who know stuff, and some who bemoan not knowing stuff and in the future there may be more. I might have been a precocious voracious learner at fifteen or so.... but you know a grown assed adult who want's to learn what they missed.... can probably match me if they want.

This is Metafilter and a thread on physics stuff and some know a good bit, some others don't and some say nothing. If you want, here's a good place to start. Grown assed adult who want's to know some physics but missed it... I'd start here.

I don't believe anything is beyond anyone who wants to know, may take some time, may take some basics, but not beyond anyone who's here reading this. If they don't really want to, fine. There may be other better things now that I don't know about, fine.

The rest is just clearing up misconceptions, I didn't actually learn physics in university. And that's like the eleventhteen time I've dropped that link in a physics thread for people to find and maybe get started if they want.

I can't help but tell people that they can know something if they want to. It's sorta morally wrong to sit around and not tell them.

I have that 40 years of experience.... not a teacher or anything, but not going to not point the curious where to maybe start if they want. Knowing something and staying silent is the worst choice. Annoy a few, maybe help some others.
posted by zengargoyle at 7:43 AM on September 5, 2023 [1 favorite]