Cosmology Physics

Rob Sheldon on dark matter as a “superfluid”

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Rob Sheldon

At Aeon, we are asked to consider the “superfluid universe.” Physicist Sabine Hossenfelder offers:

Quantum effects are not just subatomic: they can be expressed across galaxies, and solve the puzzle of dark matter

Most of the matter in the Universe is invisible, composed of some substance that leaves no mark as it breezes through us – and through all of the detectors the scientists have created to catch it. But this dark matter might not consist of unseen particle clouds, as most theorists have assumed. Instead, it might be something even stranger: a superfluid that condensed to puddles billions of years ago, seeding the galaxies we observe today.

This new proposal has vast implications for cosmology and physics. Superfluid dark matter overcomes many of the theoretical problems with the particle clouds. It explains the long-running, increasingly frustrating failure to identify the individual constituents within these clouds. And it offers a concrete scientific path forward, yielding specific predictions that could soon be testable.

Superfluid dark matter has important conceptual implications as well. It suggests that the common picture of the Universe as a mass of individual particles bound together by forces – almost like a tinker toy model – misses much of the richness of nature. Most of the matter in the Universe might be utterly unlike the matter in your body: not composed of atoms, and not even built of particles as we normally understand them, but instead a coherent whole of vast extension. More.

Proposals such a this take us well beyond the usual view of dark matter as collisionless particles that do not emit light.

Rob Sheldon writes to say in response:

In a previous post, I mentioned how the idea of a “second dark matter inflation” was a 4th epicycle on the whole “fine-tuned” Big Bang problem. That is, to avoid the conclusion that the Big Bang is designed, physicists have come up with a series of ad hoc explanations that add epicycles to epicycles.

This discussion is a different way to put lipstick on the pig, let’s call it the 4′ epicycle. Instead of invoking a second magical “inflation” for dark matter, this author thinks we could get by with a semi-magical “superfluidity” for dark matter. In both cases 4 and 4′, the problem is that dark matter should have collected in the center of the galaxy that it helped to form. Since it isn’t concentrated there, then there must be a new property of dark matter that prevents its clumping. Epicycle 4 suggested “inflation”, epicycle 4′ suggests “superfluidity”, in both cases it is an “anti-clumping” artifice.

Unlike an inflation that has never been observed, superfluidity was observed and explained in the 20th century as a quantum property of helium-3. What is weird about this paper, is that quantum phenomena aren’t supposed to be observed over distances of millimeters, and with galaxies she’s talking distances of light-years. For the record, that’s some 18 orders of magnitude bigger. If quantum mechanics had that kind of a range, we’d all be living in Gamow’s world of Mr Tompkins.

Philosophically, physicists have become so convinced of the reality of exotic particular dark matter, despite having never seen it, that they are willing to build entire castles out of their poker cards. A century ago, Ernst Mach argued that we should not accept the existence of atoms unless we had seen them, and Einstein took to heart this radical realism, this anti-metaphysicalism of Mach when he proposed his “Special Theory of Relativity”. Other scientists had done all the math–principally Poincare and Lorentz–but it took Einstein to reject the “classical” metaphysics of Newton and Kant, and accept the results of experiment as “real.”

The point of this article is that physicists are engaging in the exact same behaviors as the turn-of-the-century physicists who added epicycles like the “Fitzgerald-contraction” to keep the Newtonian universe happy in the face of contrary evidence. Being able to reject the status quo, being able to “question everything” is not a common trait, but Einstein had it.

And the common wisdom about “dark matter” is that it is an exotic particle without interactions like a neutrino. But what if it is not exotic at all?What if it is something as ordinary as black comets–which release jets of steam when encountering a star, and thus are repelled by the high star densities of the center of galaxies, and thus, all the attributes of dark matter can be represented by ordinary objects with ordinary physics. Why is this so controversial? Could it be because particle physicists are accorded more esteem, more funding than astronomers?

What I find most fascinating about these conundrums, is their sociological aspects. Like the “New Synthesis” in Darwinism, the intractable problems are neither biological nor mathematical, but always sociological. More so now than ever, because science is now done as a group project, with hundreds or thousands of kibbitzers, willing to start a twitter storm over every perceived political blunder. No wonder science has stalled in the 21st century!

See also: Rob Sheldon on the epicycles of today’s cosmology

Arrow of time points to missing dark matter?

and

Big Bang exterminator wanted, will train

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10 Replies to “Rob Sheldon on dark matter as a “superfluid”

  1. 1
    Whitehead says:

    The Cooper-Hofstadter paper is a variety of the superfluid vacuum hypothesis that has been around for a long while. While the “surface of superfluid” and “surface strain” could be fascinating turns, it appears somewhat difficult to comprehend what it could mean quantitatively – presumably in light of the fact that it implies nothing…..
    write my paper for cheap

  2. 2
    Mung says:

    The Cooper-Hofstadter paper is a variety of the superfluid vacuum hypothesis that has been around for a long while.

    You mean to tell me those guys on the show The Big Bang Theory really are scientists?

  3. 3
    Mapou says:

    What if there is no dark matter? What if physicists are just groping in the dark, blinded by their false assumptions about gravity and the way particles move? What if physicists cannot even explain something as basic and fundamental as why a particle in motion remains in motion? What if physicists are full of themselves?

    What if?

  4. 4

    Mapou,
    most of these questions in cosmology get so very hairy because they are so close to metaphysics that it really does matter what the meaning of the word “is” is. Dark matter can be parsed as two words: “dark: yet to be observed using photons and telescopes”; and “matter: substance with the gravitational properties of bending space, so that it prevents spinning galaxies from throwing out stars, and it focusses the starlight of even more distant galaxies.”

    Okay, neither of those two definitions is by itself controversial. Telescopes have never seen the back of your closet, and every forgotten shoe not only has the gravitational property of bending space, it also has the unexplained property of attracting dust. With so many things in this universe still unobserved by telescopes, there really isn’t anything magical about dark matter. So why is it getting so much press?

    First off, nothing is gained by denying its existence. We would still have no explanation for why the galaxies spin too fast while focussing starlight so well. Numerous physicists have toyed with gravity to see if they could get rid of dark matter by modifying the way space is bent, and despite some holdouts, their calculations came out all wrong, and few think this approach worth pursuing. So dark matter still remains the most parsimonious solution.

    Second, we are all groping in the dark, and mostly blinded by our false assumptions. In our more sober moments, we all admit that we have no surer path to true knowledge than an Indian Guru or a Amerindian shaman. Many of us fall back into a pragmatic view, that despite not knowing why we can be sure of knowing–As Nobel prize-winning physicist Eugene Wigner entitled his lecture, “The Unreasonable Effectiveness of Mathematics in the Natural Sciences”–we nevertheless pursue a physical explanation because it has worked so well in the past.

    In this last regard, I feel privileged to be a physicist who does know why math has been so unreasonably effective–because math is of God, and is one of the languages of heaven. Physics only makes sense if it reflects the attributes of God. But of course, that is exactly what most of the popular press are replacing with “Dark Energy” and “Dark Matter”.

    This is why I find the debate, both in the press and in the research literature, to be so very frustrating. So much bad philosophy and theology is being forced into the phrase “Dark Matter”, that I have to first explain why it is an innocuous term before I then can explain why it is being co-opted by a bunch of religious nuts. But I keep hoping that my efforts are not in vain, and that some day my colleagues will come to their senses.

  5. 5
    PaV says:

    Rob:

    I’ve still to read the Aeon article, but from your comments and inserts have got a feel for this “superfluid” notion. I wouldn’t be too quick to dismiss it.

    My own musings on the quantum world lead me in a direction very similar to theirs. If my view turns out to be correct, then they’re only a step or two away from a proper understanding.

    In the meantime, it might look like an ‘epicycle’ added to another; but, here, I think they’re closing in. I suspect that the whole notion of the ether–considered by the enlightened world to long ago have been dismissed by weighty scientists, Einstein first among them–must be reconsidered. A new vantage point must be taken. Then all falls into place (or, at least, begins to). So, I, for one, am withholding any criticism.

  6. 6
    PaV says:

    Just as a follow-up on the “ether” comment, Einstein in 1920 (21?) wrote a paper on the “ether,” saying that something like it MUST exist. Why? Because otherwise general relativity would have nothing by which it could “curve” space. Most people are completely unaware of this paper. Dirac, too, threw his hat in the ring in favor of some kind of ether. Is it the simplified notion of Maxwell’s day? Maybe; but likely not. Einstein said that the Maxwellian type of ether violated special relativity—end of story. But, there’s something out there, isn’t there? You can’t have weak charges and currents without something flowing, right? So, the superfluid notion fits in with this sort of view.

  7. 7
    Mapou says:

    Rob Sheldon:

    First off, nothing is gained by denying its existence. We would still have no explanation for why the galaxies spin too fast while focussing starlight so well. Numerous physicists have toyed with gravity to see if they could get rid of dark matter by modifying the way space is bent, and despite some holdouts, their calculations came out all wrong, and few think this approach worth pursuing. So dark matter still remains the most parsimonious solution.

    I have to disagree. Consensus means nothing on this topic because, as I said, it’s based on ignorance. If physicists do not have a causal explanation for either gravity or something as simple as motion, any conclusion they arrive at with regard to the cosmos at large is to be taken with a large grain of salt, IMO.

    Second, we are all groping in the dark, and mostly blinded by our false assumptions.

    I’m glad you agree.

    In our more sober moments, we all admit that we have no surer path to true knowledge than an Indian Guru or a Amerindian shaman. Many of us fall back into a pragmatic view, that despite not knowing why we can be sure of knowing–As Nobel prize-winning physicist Eugene Wigner entitled his lecture, “The Unreasonable Effectiveness of Mathematics in the Natural Sciences”–we nevertheless pursue a physical explanation because it has worked so well in the past.

    In my view, math explains nothing. It can only be used to describe observed phenomena. Newtonian or Einsteinian gravity equations do not explain gravity. And the equation for the inertial velocity of a body does not explain motion. It just describes it. The problem with math is that it is acausal. An explanation requires a separate abstraction, i.e., a cause-effect modelling of observed phenomena. Mathematical descriptions are screaming for an explanation, not the other way around. Newton admitted this. He knew that he could not explain gravity. All he could say is “Hypotheses, non fingo.” I wish modern physicists would do the same. Unless one understands the fundamental aspects of nature, one is likely to fall prey to superstitions. This is why I believe dark matter is superstition at best and crackpottery at worst. Same can be said of things like Big Bangs, wormholes, black holes, accelerated expansions and the like. We don’t know enough to preach about these things.

    In this last regard, I feel privileged to be a physicist who does know why math has been so unreasonably effective–because math is of God, and is one of the languages of heaven. Physics only makes sense if it reflects the attributes of God. But of course, that is exactly what most of the popular press are replacing with “Dark Energy” and “Dark Matter”.

    Math is an abstract (i.e., spiritual) system. As with all such systems, it can neither be created nor destroyed. So I don’t believe for a second that God created math (assuming this is what you are implying). It just is. Even God must be subject to it. My understanding is that physical phenomena are mathematically describable only because both math and physical reality are discrete dualistic (Yin-Yang symmetrical) systems. We can understand math because we are spiritual beings, IMO.

  8. 8

    Mapou,
    Blaise Pascal said it best–“there is a God-shaped vacuum in every one of us that can only be filled by God himself”. If Math “just is”, then a metaphysician would say you have defined math to be God. Only God is self-existent, everything else is derivative. This is why I say math expresses one of the attributes of God.

    Humorously, Sir Michael Atiyah, a famous mathematician in England, said: Algebra is the offer made by the devil to the mathematician. The devil says: `I will give you this powerful machine, it will answer any question you like. All you need to do is give me your soul: give up geometry and you will have this marvellous machine.’
    You may wonder what this has to do with math. Well when mathematicians get to the level of Atiyah, they know that math is more than a machine, it has a soul, and the essence of that soul is geometry. Spacetime. Being. And the absence of space, the absence of God, is a vacuum, as Pascal reminds us.

  9. 9
    Mapou says:

    Sheldon,

    It occurs to me that you are a doctrinarian or fundamentalist Christian. I’m leaving this discussion because I don’t think it will amount to anything.

  10. 10
    anthropic says:

    Robert, I sometimes post on a tech site called Next Big Future. Strongly materialist, to put it mildly.

    Your comments about cosmological epicycles have now made their appearance there. The fur will fly, I’ll get some more down votes, but your thoughts will provoke some of the more open minded into questioning their assumptions.

    Keep up the good work, and congrats on calling BICEP2 right!

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