Dreams of new physics fade with latest muon magnetism result
nature.com
nature.com
(Other one, still on HN front page as of while I write this https://www.theguardian.com/science/2023/aug/11/scientists-f...)
> “They are different experiments, measuring different things, and there may or may not be a connection,” he said.
It depends what answer you're looking for! We can tell you how photons behave, how to recognize them, and how to predict what they do. For hard philosophy questions, that's more under sections 100-119 of the Dewey Decimal than something physics aims to answer
>what medium is present in a vacuum that allows things like gravity to propagate
That's a little like asking who is in charge of pushing the sun around the Earth. There's a presupposition in that question, you should first ask why you expect there to be a medium, besides nondescript vacuum
We can observe and describe stuff interacting. The stuff is positioned in space. We can see that some stuff takes up space, and it can move to take up some other space. What we describe interacting is the stuff itself, the space around it is where it is.
Throw an apple through the air, and you can watch it sail through that medium. Remove the air, put it in vacuum, the apple is still able to move around despite the lack of anything meta or extra besides the apple and where the apple is.
The story is similar with light, gravity, other phenomenon. Things have some particular location in space, and that location can evolve with time.
You can still try to define the word, pick something within that description and call it a medium if you like, but it's not fundamentally necessary. And it won't be something "present in a vacuum that allows things like gravity to propagate". Things propagates on their own, their location within space simply evolves.
Like the problem of gravity is described by the curvature of spacetime. Does spacetime "exist"? If not it's just a tool, and not an actual observation that maps onto reality. In other words we don't know how gravity actually "works" and interacts or what "spacetime" is, if it is a thing, regardless of how powerful the description is. The description is just a mathematical tool that is very useful, but that's just about it.
"You can still try to define the word, pick something within that description and call it a medium if you like"
Yes... that's how language works. "Spacetime" is mapped onto something. Language is a medium of communication. Spacetime is a medium of interaction/causality. Whether such things "exist" is an epistemic discussion or a discussion for experimentalists. But any medium is just the means by which something occurs or happens. So what is the means by which gravity "happens", or exerts influence on other bodies if not the curvature of "spacetime", which itself hasn't really been established. Does gravity just magically happen?
I think using that definition is fine! I tried to talk about things positioned in space directly instead of using a notion of medium because that word comes with a lot of imagery, and it can make discussion difficult, it's easy to talk past each other when we start using words that don't have a very well settled definition
I was originally responding to a formulation where the medium is defined as something "present in a vacuum" that allows propagation of things. This is where imprecise language creates trouble, and why I don't like that word. You can say space is the medium, but you can't say space is a thing present in the vacuum that allows propagation. Vacuum is located in space, there's not a very meaningful sense in which space is a medium found within vacuum that helps things propagate, or at least that definition of the word is not very helpful to my understanding of the world
For gravity, I'm okay with calling spacetime the medium, as long as you're careful to not imagine that there's some more ethereal thing within the vacuum that physics doesn't say anything about
>But any medium is just the means by which something occurs or happens
That's fine. That's not an invalid definition. I just think it's important to separate the concept of a physical medium from more philosophical notions that everything happens in a medium, even if that sometimes means defining the word medium as an immaterial concept whose existence makes people question the definition of the word "exist".
In response to the original post, that definition of a medium inside the vacuum is something that doesn't exist. With your definition of space as the medium for gravity, you can make that work, as long as you can communicate what you really mean to other people when using that particular word!
I thought spacetime was supposed to be identical with the gravitational field. It can't be gravity's "medium" if that medium is itself gravity.
I find this extremely hard to think about; gravity both generates spacetime, and warps it. It's really hard to escape from the earthman's experience of space as a sort of instantaneous volume; we don't really experience time at all, except in the sense that we have a sense of certain events as being not the present (i.e. the past). We know that time exists in some sense; but all we experience of spacetime is the space bit.
but then, according to the Uncertainty principle, it has a less particular momentum..
She discusses nine levels of what we could call "nothing" as in "there is nothing present in this container". It may be useful since she discusses the various substrates that are still present even in what we might normally think of as a "vacuum"
[0]: What is "Nothing"? https://youtu.be/PhfqdBk8qxk
Hope I cleared that all up. Don't ask any follow up questions.
IMO, this desire to "simplify" something that cannot really be simplified is why so much pop sci around quantum stuff is just nonsense. Even normal words mean entirely different things in the realm of quantum physics. The layman doesn't understand what quantum computing does because the layman doesn't even have a knowledge of calculus, and all the intuition about the behavior of mathematical systems that comes with it, let alone the kind of linear algebra, discrete math, and higher level math like fields.
People need to stop pretending that the most advanced mathematical constructs humankind has conceived, standing on ten thousand years of the smartest minds we have ever birthed, is something that John Q Public can expect to understand.
It's no different than me being unable to discuss influences on Picaso's work because I have never taken an art history class. Sure, I could parrot some dumbed down thought someone else feeds me, but I emphatically do not have the context and surrounding knowledge to extract any meaning from that.
Photons are merely quantized ripples in the electromagnetic field (according to quantum mechanics, the momentum and energy in these ripples come in discrete chunks).
It's instructive to wonder what could possibly be a simpler ontology. Perhaps one imagines a "medium" like that of sound, consisting of little atoms of some sort spread throughout spacetime. But then immediately this would beg way more questions: what are the atoms themselves made out of? When neighboring "atoms" are displaced why and how do they affect a given "atom" in order to propagate disturbances? What other properties might these atoms have and what would such a word as "properties" even mean since they are supposed to be the elemental constituents of light/gravity itself?
According to modern physics, none of this: just 4 + 10 = 14 numbers, no substructure whatsoever.
(Of course, there are other fields too, like matter fields and gluon fields and one a necessary part of the whole story is a declaration of what these numbers look like according to different observers, but these features are just elaborations on the basic picture of a collection of numbers attached to events.)
Also quantum field theory seems be just plain bad at explaining classical phenomena, which dominate general relativity. To me at least it seems quite difficult to describe a basic electromagnetic from the QFT, other than pointing at the Lagrangian in the path integral and saying something about how contributions outside its extremum will cancel out. Though perhaps I'm simply missing some trick here.
The way to deal with that is to use mathematics. Once you yield to its power and give up trying to "understand" particle physics, things are a lot simpler (for certain values of "simple" ofc!)
They may turn out to be right, but you have to admit they sound arbitrarily made-up for lack of a better understanding.
Well, yeah. Dark matter and dark energy are the bug ticket names, so to speak. Thousands of physicists are coming up with ways to "look harder."
Dark matter and dark energy are just placeholder names for something we don't understand and don't know what it is. We didn't make them up. We just observe the effects and conclude that there must be something there that is making the universe behave the way it does.
Mostly, but they have a lot of behaviors attached to them at this point due to various measurements and accompanying assumptions. Not to mention that labeling the sets of interactions each exhibit with a single name creates the appearance to the public that they are created by a single source. Dark Matter could be several different things interacting, likewise for Dark Energy.
But you have to name them something to talk about them. There probably would have been better names, but physicists are no better at naming than programmers
Descartes, Leibniz, Hume, Kant and others, while disagreeing with each other in major ways, all agree on one big concern: We're fundamentally limited in our knowledge about "things in themselves" outside of our consciousness and the perceptions we receive.
Naively we think "oh, looks there's a flower!" but for these philosophers a big question was: how much can we really know about the actual thing that is the flower, beyond the (potentially suspect) information that our mind receives through the senses and our mental models (include the concept of 'flower').
In a very practical way I think we might be bumping into these limits. Which isn't surprising since what was driving these questions for those philosophers was concerns about the foundations of the then rapidly emerging scientific fields.
The set of sceptical propositions, say S, which make this "naive" are far more naive than the truth of there being a flower.
That era of philosophy had yet to learn that philosophical propositions are themselves subject to scepticism, and when balanced against the ordinary, are far far more doubtful.
What falls away, as naive, under scepticism is scepticism itself.
Surely you'll at least agree that the concept of "flower" is a mental object that we use to classify a set of related sense perceptions.
If you're going to call skepticism "naive" then you have to at least outline what you mean by "a flower" in relation to the experience of observing one. I think you'll find the number of propositions required is not small.
> That era of philosophy had yet to learn that philosophical propositions are themselves subject to scepticism
Hume's fundamental point was that even causality cannot be meaningfully verified as real so skepticism about philosophy itself was already alive and well at that point.
> that even causality cannot be meaningfully verified as real
So much for how awfully limited Hume's philosophy is. If your premises are insufficient to evidence ordinary propositions; so much for your premises. The toy model here is the deficiency, not the world.
> then you have to at least outline what you mean by "a flower"
I do not. Philosophy answers to reality, not the converse. When I pick up a flower, there is a flower. Our ability to put that into words may, or may not, be limited. The power of our philosophical cognition here is irrelevant.
That I am holding a flower invalidates all systems of philosophical propositions which assign that proposition 'False'. Scepticism does not falsify reality, rather, it is the converse.
That there are systems of propositions which succeed in accounting for the truth of ordinary such claims makes scepticism doubly absurd.
There is a world. It is the cause of my perceptions. My perceptions are caused by the world they present. I learn to perceive the structure of the world because the world has that structure. And so on.
I don't understand why you're even making this statement, no philosophical skeptic would disagree with this. Skepticism has always attacked our understanding of reality, not reality itself.
If anything it is the idealists, like Leibniz that argue that "reality is only in our minds", verging on solipsism. You seem to be misunderstanding Hume who more so points out that the only thing we can really "know" is our inner experience of reality, which is a bit closer to what you're arguing.
And the idea that there's an "inner experience" which is the object of our knowledge is the premise of idealism.
The objects of our knowledge are the world, directly.
When I open my eyes and see a flower, I see a flower. I don't see my seeing of a flower; nor do I see my inner experience of a flower --- where indeed, is the eye which sees inner experiences? And which eye sees that one?
This premise is the dogma of scepticism. Weighed against everything else it comes out vastly improbable.
When I see a flower, the object of my seeing (and my knowing) is the flower. My knowledge consists in having the experience of the flower, as caused by the flower. Without much scientific knowledge I do not know, indeed, that I am having an experience of a flower.
This talk of "having experiences" is a post-theoretical description of an event which is much more primitive. A dog which sees a flower knows there's a flower in front of it. It knows basically nothing about what kind of experience its having.
The dog succeeds in being oriented to the world as it is; the dog succeeds in knowing. As do we.
Neither of us are oriented towards ourselves. We are not peering inside our heads. Such muddles are the religion of scepticism.
Then you must have a fundamentally different qualitative experience of consciousness than I do.
The flower I am holding right now, it is real to me because I can observe myself experiencing it, however the flower you are holding I cannot experience because I am not observing your experience of observing the flower.
It is quite remarkable that you can experience that flower that I am holding and say that it's real while I cannot do the same for the flower you are holding.
> "A dog which sees a flower knows there's a flower"
I certainly don't know enough about the state of my dogs mind to know that my dog is seeing a flower, as opposed to say, merely experiencing clustered sensations in the same location as I am seeing a flower. I've looked at a flower and seen my dog eat it, so I have a suspicion that he recognizes something there, but only because my beliefs about how his actions might correlate with seeing something.
I also have friends who have seen a purple flower in the exact space I am looking where I cannot see a purple flower. What is the explanation for this?
There is no such thing as "real to me". You are observing a flower. Seeing that flower means having a visual perception caused by that flower. That visual perception presents your knowledge (indeed, is) your knowledge that there is a flower.
When I look at you holding a flower I see the flower and I see you holding it. There's no mystery here. The objects of my seeing are things in the world. There is no 'private world'.
> I certainly don't know enough about the state of my dogs mind
What you 'know enough' to say is irrelevant. The proposition that the dog is seeing a flower is true regardless of what you do, or do not know. Knowledge models reality --- reality doesn't model knowledge. The proposition is true; your theory of knowledge should be revised to account for it.
> I also have friends who have seen a purple flower
The presentation of knowledge we call a visual perception, uses the mechanism of presentation we call 'my visual system' (which includes what I have learned to see). Just as a mountain is presented by different cameras, with different lenses, in different perspectives.
Insofar as I make linguistic utterances based on this presentation I'm engaged in theorising about the causal origins of my perception. Here mistakes are possible, but quite uncommon. If we think the stick is bent, we need only take it out of water to realise that the prior visual perception was caused by the refraction of light.
In this manner we learn what the causal origins of our perceptions are; and hence, rarely make mistakes.
Visual systems may be better at recognising some features of the world than others -- some cameras have zoom lenses. Likewise some may be broken. How your visual system presents your knowledge via seeing is arbitrary (water color, pastel, chalk...). Its built only to ensure that you can reliably infer its causal origin (ie., properties of the world).
But this theorising is irrevelant to what's going on. The propositions, "i know there is a flower", "there is a flower", "i am seeing a flower directly" etc. are all true. Our ability to give a linguistic account of the causal origin of this knowledge is fallible, but reality isnt.
Hofstadter in GEB refers to positions like these as "axioms": statements that are impossible to formally prove within a particular system but from which we can derive statements that follow from those axioms through rules (the most fundamental of which are themselves axioms, like the statement in geometry that two points make a line) governing symbolic manipulation within a particular system. I like the concept and find it useful for wrangling logic and philosophy although I also note that it is itself subject to accepting certain axioms.
" but by definition we can't perceive what's beyond our perception "
This is one of those sceptical propositions I'm talking about. All these sceptical claims which follow "by definition" follow only by the definitions of sceptics -- definitions held (with no sense of self-awareness) with certainty.
How I would define "perception" would make such a claim incoherent or trivially false.
The light which hits a camera from a tree does not travel via some daemon. And a camera so-positioned can indeed photograph its own mechanism.
We have for at least half a century being using perception, without trouble, to perceive the mechanism of our own perception (visual cortex, retina, lenses, etc.).
All these alleged impossibilities begin from the premise that we are not within, part of, and directly causally engaged with, the world.
This is the most outrageous of all 'philosophical' propositions, the most naive, the most absurd --- and yet lies as the undoubted presumption of nearly all scepticism.
The idea that we should discount science based on rhetoric vs science based on evidence still isn't a popular one in the lay community. People hate being told that there are things they may never understand, because the human brain is just a really good monkey.
There is no evidence in rhetoric, and a more convincing argument should not be considered a more realistic one.
We is used colloquially. I am not a physicist. I am a mathematician working as an SDE.
When teaching ML I talk about adding loops to the Ptolemaic planets-orbit-the-Earth-model - and how it actually worked pretty well because they spent a lot of time adding loops to the orbits to make it fit. It was overfit.
> Overfitting is an undesirable machine learning behavior that occurs when the machine learning model gives accurate predictions for training data but not for new data.
However, most of the particles introduced in physics have been done with concrete predictions. For instance, when the top/bottom quarks were first proposed (1973-1975) the theoretical paper also included a bunch of predictions. In the following years all of the predictions turns out to be true.
Trust me, everyone wishes the Standard Model was simpler and was more "fundamental", but no one has figured out how to make it work. I'm not quite sure how "overfitting" fits here.
With enough lawyering, one can argue that statements around whether model #53sa7r describes a phenomenon accurately qualify as hypothesis. But the success or failure of such hypothesis rarely make for interesting papers to anyone but statisticians.
And they don't often contribute to the human ability to reason about reality, build new things or predict the future. Like econometric models that never forecast with accuracy >10 years in advance.
That should be very satisfying.
Einstein "simply" took the observation that the speed of light is constant in all reference frames, and relativity followed from that. Granted, he had to throw out the idea that time is constant.
So what assumption might we take for granted that needs to be thrown out? Or more specifically what is the core set of things that conflict between QM and relativity? I'm asking for something far more specific that "QM and relativity can't both be right". It's in details that are probably way beyond my understanding.
A true paradigm shift that would have implications in our scales would be much more meaningful.
Or creative ways of using large masses, like planets and even stars, to make measurements of tiny things - similar to how Earth-size telescopes can be approximated by much smaller ones, spread over a large area.
But this for example is so freakishly absurd that it seems impossible even for scifi.
A type 3 civ, if it exists, could potentially do that; but it’s one thing to extract energy off stars, type 2 and 3 and another thing to manipulate the inner core of neutron stars.
Tangible ambiguities and loose ends are mostly evident in cosmology,eg in the form of this or that "dark stuff" but it is conceivable there are other very subtle phenomena hidding in plain sight (e.g., accessible with desktop experiments)
An indicator of this is show in the plot from the Fermilab presentation here[2], where they replaced the previous low-energy e+e- data (from LEP?) with that from CMD-3 and got a result which agrees very well with the lattice calculations.
The presentation also contains a nice intro to the whole Muon g-2 thing btw.
[1]: https://www.physicsforums.com/threads/when-will-fermilab-rel...
That is the significant step change here.
Being wrong is just as much part of science as being right. ...all part of the process.
It's used in the very old sense of "perplexing", not "to make someone feel awkward".
1b, not 1a: https://www.merriam-webster.com/dictionary/embarrass
And that's been an embarrassment well-known for the last century. The word has a metaphorical use of the sore spot, that which sticks out, which is ugly, which is confusing or awkward. "This code is embarrassing" doesn't necessarily mean the author should literally feel embarrassment. It's just messy. (Yes, really. It's in the dictionary as a sense of the word.)
What is the gain exactly in using language (like "embarrassing") that discourages mistakes and makes people feel worse about being wrong (even if they technically shouldn't). Plenty of better words exist.
Side note, I would definitely feel embarrassed if someone publicly called my code "embarrassing". Even if I shouldn't.
I suppose "how to talk to journalists" should be a major skill of scientists, but really: no matter what they say, you know journalists will turn it into "Scientists Now Claim Parallel Universe Full Of Aliens".
"Common sense" isn't merely a myth, but also often is propaganda, that everything we know is obvious and easily understood by a layman from first principles that you can reason through, rather than having to rely on extremely specialized people to do real tests of things we think we "know" to find out what reality is.
Remember that next time someone wants to push "Common Sense" regulation on anything. Humans are explicitly ANTI-rational creatures, and the ONLY defense against that is to verify everything we can against reality's judgement.
At no point could anyone have just "thought about it harder" to get from aristolean physics to Newtonian physics. Rhetoric cannot provide answers or new information, it can only convince.
Our corner of the universe has particular physics, but other places have other physics.
That's why far off galaxies are moving too fast, and why there seems to be not enough matter and energy to explain distant gravitational effects.
There could be multiple layers of parameterization before "what we know as physics" falls out. The stuff behind what we know as physics? We don't even have words for those meta-forces and meta-meta-forces, (maybe like, derivatives of derivatives).
And what if it's not just a "linear scale" where other places have the same forces, but with different "strengths", but other places in our universe have a completely different set of forces and laws.
What if aliens just found a way to "bring a bubble of their own physics" into our little corner? That's why it seems so inexplicable to us, because it's literally alien physics.
https://www.pbs.org/wgbh/nova/article/are-the-laws-of-physic...
I wonder if this is the case at the “bounds” of the universe or why there are so many inverse or at least non-linear relationships between various forces. My thought is that you can’t get outside the universe, because space becomes warped in the sense that a short distance is extraordinarily “long”.
The problem with any discussion about these kinds of things is that there is zero information actually being exchanged. Our brains have several assumptions built in, like a concept of time. "Going outside the universe" is not something that can rigorously be discussed because "outside" probably isn't even something defineable """outside""" our """universe""". Hell, even the concept of "defining" something is entirely a starting assumption.
It's like asking "what happened before the big bang?", well, "happened" is not something that even can be defined "before" the big bang. None of our definitions of ANYTHING can EVER make sense outside of our reality, or one that is nearly identical to it. Even "reality" is a definition that presupposes itself.
Essentially, it's a malformed question, like "What time is blue?", there's no way to turn such a question into a meaningful evaluation.
And how can we really know what's going on out there from so far away?
Why did we need to invent the 'darknesses', and reschedule the big bang, if it's really just the same as here, and we understand it so well?
They are. One parameter, for instance, is the strength of the electromagnetic field at your location. Another is the sum force of gravity acting on you. Another parameter is your current acceleration.
The point being: that doesn't help you actually explain anything. Okay, great, that's why far off galaxies are moving too fast; they have different parameters that are making them do that. Can we actually figure out what that parameter is? Let's come up with a name for it so we can actually discuss the same thing. Let's call it, oh, I don't know, "dark energy".
Sure, the speed of light, or the permittivity of vacuum, could totally be different somewhere else. We have no evidence for that and it doesn't really help us explain anything, but if it did, then great: we figure out how that new parameter behaves and varies, which will inevitably involve something else that is constant, and then that constant becomes part of our new theory. And then someone on Hacker News comes along and says "why are we just assuming that that constant is the same everywhere? Maybe other corners of the universe have different physics! Checkmate physicists!"
It reminds me of the creationists who endlessly argue about "missing links" in evolution despite us filling in Earth's evolutionary history more and more every year. There's no insight here, you're just moving the goalposts around.
> We don't even have words for those meta-forces and meta-meta-forces, (maybe like, derivatives of derivatives).
It's called "jounce", actually. Or some people prefer "snap", followed by "crackle" and "pop", of course.
> What if aliens just found a way to "bring a bubble of their own physics" into our little corner? That's why it seems so inexplicable to us, because it's literally alien physics.
Hallucinogens may beget good music, but not very good physics.
In other words, the outside universe has moved on 200 billion years from the point of history that our "diorama" re-creates.
Earth is one of hundreds of "ancient cores" that proved significant in the eventual development of a cosmic civilization, and in honor of our legacy, we are semi-faithfully (plenty of creative license!) re-created in an artificial bubble complete with its own legacy physics (because of course physics evolves over time as well!).
So we're one of many "attractions" in a vast "theme park" that is mostly used for historical scholarship, sightseeing and alien tourism. Yay!
The headline seems to differ from the rest. They seem to suggest that the preprint paper is entirely accurate and that our previous calculation method was incorrect.
Am I interpreting this correctly? Is this just a bad and missleading headline?
> embarrassment (n.)
> 1670s, "state of being impeded, obstructed, or entangled" (of affairs, etc.), from embarrass + -ment, or from French embarrassement, from embarrasser.
> As "a mental state of unease," from 1774. Meaning "thing which embarrasses" is from 1729. Earlier words expressing much the same idea include baishment "embarrassment, confusion" (late 14c.); baishednesse (mid-15c.).
It is natural in a language that words are being used in older alongside with newer connotations. "He was embarrassed by the embarassment of riches on display" is maybe awkwardly worded but possible nonetheless.
This is a high energy physics thing about failing to find something beyond the standard model. Just your regularly scheduled "5 sigma physics anomalies that disappear on their own with better measurements" programming.
https://www.theguardian.com/science/2023/aug/11/scientists-f...