back to article Nope, we can't find dark matter either, says LUX team

An international team of researchers working on the Large Underground Xenon dark matter experiment announced today that they have failed to detect any dark matter particles. Results from LUX were presented at this year’s Identification of Dark Matter conference after the team completed its final 20-month run of the detector …

  1. DNTP

    371kg of cold liquid xenon

    Too bad they didn't detect anything, it was a noble effort.

    Seriously, though- nondetection does not imply that the experiment was uninformative (and therefore uesless). If a certain particle model predicted that a detectable event was highly probable within the 20-month period, then the negative result means that the scientists studying dark matter need to re-think either the detectability threshold of an interaction, or the validity of the model.

    1. Anonymous Coward
      Anonymous Coward

      Re: 371kg of cold liquid xenon

      "Too bad they didn't detect anything, it was a noble effort."

      I see what you did there, and was not too inert to vote you up.

      1. Paul Crawford Silver badge

        Re: 371kg of cold liquid xenon

        I should react to that, but seem to find my shell full just now.

        1. Cynical Observer

          Re: 371kg of cold liquid xenon

          And I get left with some silly pun because all the best elements argon!

          1. Paul Crawford Silver badge

            Re: 371kg of cold liquid xenon

            At least you did not go for anything kryptic...

  2. FBee

    LUX-ZEPLIN?

    Needs heavy metal, not noble gas - LED-ZEPLIN

    1. This post has been deleted by its author

    2. x 7

      Re: LUX-ZEPLIN?

      LUX-ZEPLIN experiment.?

      well if that experiment is going to work, the Zeppelin will need Helium, not Argon

  3. This post has been deleted by its author

    1. Brewster's Angle Grinder Silver badge

      Re: "Scientists named it dark matter as it did not seem to emit any light"

      No, it was called dark matter because we couldn't see it: we estimated the mass of the galaxy by counting stars and by looking at how fast they rotated; there was a discrepancy that increased the further out you went. So we inferred there was a lot matter that wasn't in stars -- matter that wasn't emitting light; dark matter.

      It's true WIMPs wouldn't interact with the EM field. But it could be ordinary baryonic matter if you could come up with a good explanation. Many years ago I did a study looking at whether dust lanes might be obscuring stars, causing us to underestimate the amount of light-emitting matter (at the time, it wasn't ruled out).

      1. entropyk48

        Re: "Scientists named it dark matter as it did not seem to emit any light"

        Maybe could it be dark matter because it is matter that has been sucked into a black hole? And maybe there are universes of WIMPs that are still quantumly entangled with matter in our side of the black holes, since gravity is still so unexplainable? I dunno, just wondering....

        1. lglethal Silver badge

          Re: "Scientists named it dark matter as it did not seem to emit any light"

          I'm going to throw an idea out, feel free to shoot it down if someone has data! :)

          Could the missing mass in our view of the universe simply be that we are undervaluing the amount of mass found a) in star systems (i.e. planets, meteor debris fields, star system dust, etc all add up and we are just underestimating that for the star systems we see out there?); and b) that we are massively underestimating the number of brown dwarfs and other "star" systems that never actually became light emitting "star" systems? What I mean by that is that I can imagine MANY star systems existing that feature at their centre a Jupiter-like "star", i.e. an almost star, not large enough to actually ignite. This would still have a fair bit of mass, but would not emit detectable light.

          Since we can track down so many star systems, and so many brown dwarfs, surely there would be an even larger number of "star" systems which never made it to light emitting status, because there just wasn't quite enough dust around. They would also be relatively small from a viewing perspective (a Jupiter sized exoplanet is only really visible when it crosses in front of its parent star, and we measure the change in light. This is only confirmed when it actually does an orbit in front of the star. A Jupiter sized star system is not in orbit and so would be super hard to detect by current methods.

          Anyone see anything obvious with this idea which shoots it down entirely?

          1. cyfahead

            Re: "Scientists named it dark matter as it did not seem to emit any light"

            @iglethal: I agree... the problem may be largely one of experimental capability

            The most recently released 'switch on' of the SKA 16 element segment in South Africa increased the known galaxies in a moon sized area of the sky from 19 to somewhere near 1200 in the few minutes it took to collect some radiation. It looks like the brown dwarf content of galaxies also looks set for some serious revision... perhaps also 2-order of magnitude like at 'proto-SKA' . SKA will have 4 types the resolving power when complete at 64 elements. But then it will link with the Australian and South American patches in a substantially more sensitive composite array. Can we reasonably outlook a 10-magnitude increase in galactic count estimates... when looking out of the Milky Way!!?

            How many orders of magnitude of underestimation do we need for us to fully account for 'dark' matter?

            If galactic bending of light is greater than expected from current mass estimates we also need to consider where those estimates of galactic mass come from. Are we extrapolating errors that we make due to brown dwarf underestimation in our 'reference' galaxies?

            Just an observational issue... from a lay perspective. If you put a bunch of garbage in a wind centrifuge the heaviest items fall near the centre and the lighter stuff accelerates out to the periphery. If you have more light stuff than heavy stuff then the most mass ends up 'out there'. Just look at where and how gas giants form sweeping up the light far flung elements in solar systems.

            So why do the great and revered amongst us not apply the same expectation to the construction galaxies and integrate that with the expansion from the big bang? Putting Big Bang trajectory components aside for the moment. We can expect a great deal of unlit and widely scattered small light, and un-lit, objects at the edge of galaxies where they will tend to contribute to faster angular momentum.

            These objects will have built up from ejecta of star deaths, and at an earlier stages perhaps from the big bang condensations, and will have transferred some of the energy of their original acceleration along their original path into 'orbital' energy, as their path is bent towards an arc under the gravitational influence of the heavy matter at and nearer to any galactic object they approach, They will acquire the galactic spin direction if they are captured or may be sling-shot off to some other destination until they get captured. So we have a picture of galaxies 'hoovering up' light objects which tend to attach to their periphery and of heavy objects with greater momentum penetrating closer to their centres and accumulating there before gaining a measure of 'orbital' stability. Since small stuff, starting at the elemental levels, in the universe seems to outweigh big stuff we can expect more mass at lower densities to be captured in the periphery of galaxies than at their centres... since all galactic mass is acquired in the same way (just like planetary masses). They do not create their own mass nor is it all 'given' by their aggregation of locally present material in a wrinkle of expanding space time determined by the matter distribution at the time of its condensation. The pot has been stirred many times since then while it continues to boil vigorously!

            Is that a suitable practical basis for building an explanatory model of why the outer edges of galaxies seem to spin faster than we would expect them to when considering the theory together with the very incomplete measurements we have acquired in, what is after all only, the last couple of decades?

            Rob E Jarvis

          2. Anonymous Coward
            Anonymous Coward

            Re: "Scientists named it dark matter as it did not seem to emit any light"

            "Could the missing mass in our view of the universe simply be that we are undervaluing the amount of mass found a) in star systems "

            It's actually all in missing socks and coathangers.

          3. gdp

            Re: "Scientists named it dark matter as it did not seem to emit any light"

            @lglethal wrote:

            >I'm going to throw an idea out, feel free to shoot it down if someone has data! :) Could the missing mass in our view of the universe simply be that we are undervaluing the amount of mass found a) in star systems (i.e. planets, meteor debris fields, star system dust, etc all add up and we are just underestimating that for the star systems we see out there?)

            No. There is independent evidence for the amount of "normal" (AKA "baryonic") matter in the Universe based on the observed "photon to baryon ratio," as well as via the abundance ratios of Hydrogen to Helium, Deuterium, and Lithium produced by fusion reactions during the "Big Bang" (in the literature this is referred to as the "Nucleosynthesis Bound").

            The upper bound on the amount of "baryonic" matter in the Universe is only a factor of 2 more than the amount of "luminous" matter observed in galaxies, but it is ~5x smaller than the estimated amount of "Dark" matter in the Universe as estimated by cosmological dynamics, and also via the masses of galactic and galactic-cluster halos as estimated by either stellar dynamics or gravitational lensing.

            Thus, several different lines of argument all converge on there being ~5x more "Dark" than "Baryonic" matter in the Universe, and on at least half of the baryonic matter being in some "visible" form. This agreement between several different lines of reasoning is called "Cosmic Concordance" AKA "The Concordance Model" in the literature.

            The "Dark Matter" in the Universe in turn is is only about 1/3rd of the estimated amount of "Dark Energy."

      2. deconstructionist

        Re: "Scientists named it dark matter as it did not seem to emit any light"

        Actually dark means we "don't know" just like dark energy or dark flow , Dark relates to effects witnessed in the real world to which we have no clear definition to what they are.

        It's about "not understanding" not about "not seeing" or "does not emit light", and this is another experiment which re-enforces that.

        But a negative is sometimes as good or better than a positive, as it removes veils of theory that sometimes obscure the truth .

  4. Byz

    Where you see dark matter mentioned

    Think god of the gaps.

    So instead of some asking "why do galaxies rotate like that" and someone replying "God did it", we now say "it's due to Dark Matter".

    Just a different name for our ignorance.

    1. Robert Helpmann??
      Childcatcher

      Re: Where you see dark matter mentioned

      Just a different name for our ignorance.

      Well yes, except for the bit where the existence of dark matter can be tested for.

      1. David Webb

        Re: Where you see dark matter mentioned

        We can test for the existence of God using exactly the same tests that they used, and get exactly the same results.... Science, got to love it :D

        1. Martin Gregorie Silver badge

          Re: Where you see dark matter mentioned

          We can test for the existence of God using exactly the same tests that they used, and get exactly the same results....

          Not exactly the same, no.

          First we need a falsifiable God theory that makes testable predictions and I don't think we currently have one of those. Once we have that, and only then, we can run God tests.

          1. Anonymous Coward
            Anonymous Coward

            Re: Where you see dark matter mentioned

            "First we need a falsifiable God theory that makes testable predictions and I don't think we currently have one of those. Once we have that, and only then, we can run God tests."

            In fact we have had many falsifiable god hypotheses and they keep getting falsified, e.g. it rains because a god is jacking off. It's just that a lot of people refuse to believe it each time it happens. There is no God theory because no religion has ever been able to put together a framework of rules (laws) that provides an explanation for a set of hypotheses that have not been falsified, and that has predicted new observations.

            1. Anonymous Coward
              Anonymous Coward

              it rains because a god is jacking off

              I think you've got the concept of falsification wrong. To falsify that one you would need to see a god jacking off without rain or witness rain while simultaneously observing all gods keeping their hands where you can see them. Think about that for a while and you'll see why religion is not falsifiable (and hence irrelevant as far as philosophy of science is concerned).

              1. This post has been deleted by its author

      2. You aint sin me, roit Silver badge

        Re: Where you see dark matter mentioned

        It's a placeholder for an answer that will explain what we see. Recognition that we don't yet have the answer.

        Quite the opposite of a God, which is the answer itself.

        By the way, I thought it was "Dark" because it didn't *interact* with light. You can't shine a light on it because it will not absorb or reflect light or interact with it in any way..

    2. DNTP

      Re: Just a different name

      Except that the dark matter hypothesis makes physical assertions that could be eventually confirmed or rejected experimentally, leading to the refinement/acceptance/rejection of the model, and the God Intervention hypothesis doesn't?

      We as a species used to believe that "God Intervention" was a perfectly good explanation for things like tides, sunrises, lightning, rainbows, why-are-all-these-animals-here, etc, until we discovered that the universe (as befits the creation of a god) is more like a fantastically intricate interlocking machine, than a set of construction bricks simply being moved around by a greater intelligence.

  5. Anonymous Coward
    Anonymous Coward

    Have they tried down the back the couch? Seriously, everything ends up there, I just found my tv remote after it went missing for two whole months, I even got an all for one remote to replace it.

  6. keyvan

    "Scientists named it dark matter as it did not seem to emit any light"

    Actually, when dark matters hit earth’s atmosphere, the annihilation of dark matters with atmosphere emit high energy photos called gamma rays. Physicists can see the those gamma rays by gamma ray telescope. This can be consider as indirect observation.

    1. Brewster's Angle Grinder Silver badge

      Re: "Scientists named it dark matter as it did not seem to emit any light"

      It's "dark" because it's not in stars; not because it's incapable of emitting light - directly or indirectly.

      1. Anonymous Coward
        Anonymous Coward

        Re: "Scientists named it dark matter as it did not seem to emit any light"

        "It's "dark" because it's not in stars; not because it's incapable of emitting light - directly or indirectly."

        Perhaps you could have a word with both Wikipedia and dictionary.com, because they don't agree with you.

  7. Bucky 2

    The findings are consistent with my modified Terry Pratchett theory that we all live on the back of a giant turtle, swimming through the aether, on his way to mate (the "big bang").

    The aether has mass, but being ubiquitous, it is impossible to detect because we have no concept of its absence.

    Also: "There's no dark matter, really. Matter of fact it's all dark."

    1. BugabooSue
      Thumb Up

      @Bucky 2

      Also: "There's no dark matter, really. Matter of fact it's all dark."

      Nice 'Floyd' Reference. :)

      .

      @ Brewster's Angle Grinder

      One of the coolest handles I've seen (I post elsewhere as Pockels' Cellmate)

      Susi xx

  8. DJV Silver badge
    Joke

    At least...

    At least they weren't trying to find something really elusive, such as integrity in a Tory or UKIP MP!

    1. Anonymous Coward
      Anonymous Coward

      Re: At least...

      Andrew Tyrie. Easy. I'm a pinko leftie myself, but I recognise a good MP when I see one.

  9. ocratato

    Antimatter

    My wild guess is that we will see some interesting recalculations about the amount of dark matter in the universe in a year or so when CERN's experiment to weigh some anti-hydrogen is performed and they find it falling up.

    (Roughly - you fall down because the Earth's mass causes a small distortion in space-time that results in the time component having a small spacial component in the direction of down. Antimatter particles are equivalent to ordinary matter with the time dimension reversed, hence in the same gravity field their future is our past, and hence they fall up.)

    As yet there is no convincing argument as to why there is more matter than antimatter in the universe, so perhaps the antimatter does exist, but is in the intergalactic spaces providing a pressure that allows the observed rotational distribution of stars in galaxies and might also explain dark energy pushing the galaxies apart.

    1. cyfahead

      Re: Antimatter

      #ocratato: mmm... You have eclectic cultural tastes?.. mashed okra and sweet potato, or just the american spud. A friend is a stranger you do not know.... Hi! ... or a non-sibilant Socratean.

      I wonder if anybody has done a full-scale mathematical modelling of general relativity, combined with an objective re-interpretation of experimental observation, in which gravity is not presumed to be an intrinsic property of matter but is in fact the resistance of the aethereal space to its compression by matter taking up some of its space? Does Gravity suck? Or is it just Aether being pushy?

      At many levels it seems a reasonable counter-hypothesis and if true would perhaps help to unify the Quantum and Classical views of the Universe. Light matter has more interstitial voids and smaller particles than do heavy elements and disturbs less of the 'quantum-level' aether eliciting less 'push-back' from it. Aether compression nearest to concentrations of matter would still cause space-time distortions which would cause pass light to bend accordingly. Would we, at a human level, in fact actually see any differences in the normal operation of stuff around us?

      I suspect that every second mathematician will throw formula to show it does behave differently based on observations made in physical laboratories, but how many of those refutations will be tautological? In the sense that the setting up of the maths used was based upon the 'suck' hypothesis in the first place... or else are the theoretical inferences derived from measurements of physical effects which are only indirect observations at best of the reality being inferred to be the cause of those observable effects being measured and hence determined the design of the experiment being relied upon.

      Has anybody any idea if the 'Aether is pushy' concept is definitively refuted or that research in it just suffers, at this point in time, from being the world's least advisable career move? Meet me on Researchgate with an answer... Robin Edward Jarvis

  10. Neoc
    Trollface

    "..a [sic] even more sensitive LUX-ZEPLIN experiment."

    Now *there's* an experiment just begging to crash-and-burn.

  11. Silvergunner

    Another blow to Supersymmetry

    As far as I know, the theory of WIMP is mostly inspired or linked to Supersymmetry (hidden huge 'partners' of regular subatomic particles). With the failure to find WIMP and all results from LHC consistent with the Standard model, shouldn't it be time to abandon Supersymmetry and look elsewhere for an explanation?

  12. Brian Allan 1

    How about just looking for an alternative theory to dark matter/energy!? There are several excellent theories available.

  13. KamalRajpal

    Dark Matter

    http://vixra.org/pdf/1303.0207v3.pdf

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