Australian Student Uncovers the Universe’s Missing Mass

Article written: 25 May , 2011
Updated: 24 Dec , 2015


Not since the work of Fritz Zwicky has the astronomy world been so excited about the missing mass of the Universe. His evidence came from the orbital velocities of galaxies in clusters, rotational speeds, and gravitational lensing of background objects. Now there’s even more evidence that Zwicky was right as Australian student – Amelia Fraser-McKelvie – made another breakthrough in the world of astrophysics.

Working with a team at the Monash School of Physics, the 22-year-old undergraduate Aerospace Engineering/Science student conducted a targeted X-ray search for the hidden matter and within just three months made a very exciting discovery. Astrophysicists predicted the mass would be low in density, but high in temperature – approximately one million degrees Celsius. According to theory, the matter should have been observable at X-ray wavelengths and Amelia Fraser-McKelvie’s discovery has proved the prediction to be correct.

Dr Kevin Pimbblet from the School of Astrophysics explains: “It was thought from a theoretical viewpoint that there should be about double the amount of matter in the local Universe compared to what was observed. It was predicted that the majority of this missing mass should be located in large-scale cosmic structures called filaments – a bit like thick shoelaces.”

Up until this point in time, theories were based solely on numerical models, so Fraser-McKelvie’s observations represent a true break-through in determining just how much of this mass is caught in filamentary structure. “Most of the baryons in the Universe are thought to be contained within filaments of galaxies, but as yet, no single study has published the observed properties of a large sample of known filaments to determine typical physical characteristics such as temperature and electron density.” says Amelia. “We examine if a filament’s membership to a supercluster leads to an enhanced electron density as reported by Kull & Bohringer (1999). We suggest it remains unclear if supercluster membership causes such an enhancement.”

Still a year away from undertaking her Honors year (which she will complete under the supervision of Dr Pimbblet), Ms Fraser-McKelvie is being hailed as one of Australia’s most exciting young students… and we can see why!

46 Responses

  1. Aussie, Aussie, Aussie, oi, oi, oi!!

    (Pity they are mostly incoherent fields of only a few micro Gauss, though.)

    • Ian Manson says

      I look forward to the day that chant finally dies and never re appears.
      The British sing great long songs and all we can muster is a lousy 2 word chant…

    • Anonymous says

      Waltzing Matilda is alright, and I’ve heard that sung at Aus v Eng rugby and cricket matches. Seeing as it’s a song about a criminal, you’re drawing directly on your country’s cultural lineage too!

  2. Anonymous says

    This is somewhat unexpected. There are no links here, so I can’t read further. However, I am wondering if I am to presume this changes luminous and dark matter’s percentage in the universe from 4% and 24% respectively to something more like 8% and 20%. This is just based on the doubling statement in the article.


  3. Anonymous says

    This is somewhat unexpected. There are no links here, so I can’t read further. However, I am wondering if I am to presume this changes luminous and dark matter’s percentage in the universe from 4% and 24% respectively to something more like 8% and 20%. This is just based on the doubling statement in the article.


  4. the one says

    Comic Microwave Background Courtesy of NASA / WMAP Science Team(comic or cosmic)?

  5. You go, girl! A good job that proves science is still a valid pursuit for promising students.

  6. Anonymous says

    Unfortunately the details are sketchy as usual in the mainstream media with regards to how much”missing matter” was found. This is however measured evidence and appears to be legit. The findings are consistent with what was theorized. What is cool here is the methods where this student with technical expertise in the x-ray field pulled a rabbit out of a hat with the data which originally appeared inconclusive do to significant uncertainties.
    This is a link to the abstract/article which is accepted but pending publication:

  7. Member
    Steve_Nerlich says

    I think the deal is that this study confirms Bregman’s prediction outlined here:

    The universe recipe of 74% dark energy, 22% dark matter and 4% baryonic is unchanged. It’s just that Bregman predicted that a lot of the baryonic matter would be in the form of Warm-Hot Intergalactic Medium (WHIM) – or filaments. This appears to be confirmed now, so good science all round.

    I’m not sure what the link with Zwicky is – who is not obviously cited in either the Fraser-McKelvie or Bregman papers, but might have missed something.

  8. Anonymous says

    I read the paper, which does make a case for high signal statistics. Even for filaments restricted to superclusters this gives n = sqrt{S/jL}, S = surface brightness, j = emission coefficient, and L = length through filament, with ~ 5?. So the statistics look pretty good. The number density n is the 2.6×10^{-4}cm^{-3} for the X-ray energy in the range.9-1.3 kev . That is about 10^2 electrons per cubic meter. This is 2 orders of magnitude larger than H density in intergalactic space. Clearly this also means there are an equal number of protons per unit volume as well.

    This density of dark matter is about 2.4×10^{-22}kg/m^3 in a galactic halo, which corresponds to a figure somewhat larger than about 10^4 proton mass equivalents per m^3. So it appears that this result is not able to account for dark matter, as it is around two orders of magnitude lower than what is needed.


  9. HeadAroundU says

    Very confusing article. 😀

  10. I was studying mercury for a school project then I found this article and I only understood two words: year and a 😛

  11. Jon Hanford says

    I see the same confusion here as at other sites reporting this story. Dark matter is NOT directly mentioned at all in the paper. The paper discusses the discovery of X-ray emission from hot *baryonic* matter (gas) that was theorized to exist in filaments between galaxies and galaxy clusters. The original press release is rather vague and confusing on this matter (but it too has no mention of DM).

    Of course, this discovery does have implications for the study of DM in these filaments (useful in constraining DM models of filaments, for one), but this could be seen as peripheral to what is discussed in the paper (hence no mention of it there).

    I’m a bit confused too as to claims of *discovery* of this postulated WHIM (see the 2 links posted by Al Wilson here).

    • Anonymous says

      The UT article here appeared to imply a massive amount of matter was found, but in looking at the actual research paper this looks like a few percent adjustment in favor of luminous matter, but not a major shift in the distribution of matter in the universe. This might change the luminous and dark components of matter from 4.5% and 23% to 4.7% and 22.8% or something like that.

      I suspect that most of this matter which is observed here, or inferred from ROSAT data, is gravitationally bound to dark matter in these filaments. The observed 10^2 baryons per m^3 may not be sufficient to maintain a structure bound by gravity from this matter alone.


  12. Anonymous says

    A Nobel Prize ?

  13. This link is to an image from her Facebook page… She seems like a typical, care-free, goofy college student. I love it that the internet grants us the ability to immediately access information on a person at this level. It makes the sober text of a news article crackle to life, adding SO much more depth and ‘wholeness’ to it’s contents. Cute image of her and a dog, BTW… How cool. ‘^.^,

  14. Anonymous says

    The missing dark matter is due to the mistaken and unproven belief that Newton’s law of gravity is a universal law valid at cosmic distances although it is only based upon observations in our solar system.

    When used in conjunction with observations of motion of stars in spiral galaxies (by Vera Rubin) Newton’s gravitational constant does not agree with the observations unless massive amounts of dark matter is proposed to provide the necessary gravity to explain the cosmic observations.

    Actually basic physics equations suggest that for the observed balance of inward forces and outward forces of rotation show that the product of the central mass and the gravitational constant G is a linear function of distance r and for the observed case of constant rotation velocity v, the product of M and G is a linear function of distance to explain the observations.

    Rather than assigning the distance dependence to M requiring dark matter, we should assign the r dependence to G which is already invisible to give additional gravity in the form of G + A*r .

    This isdifferent than the MOND theory of Milgrom which involves acelleration.

    The linear term only becomes significant at cosmic values although it cab detected in our solar system to explain the very small changes in gravity is shown by the NASA Pioneer 10/11 space probes.

    It is time for abandoning the search for dark matter.

    Sol Aienberg, PhD

    • Torbjörn Larsson says

      LOL! When an observation comes up that tests the standard as consistent with observation (missing, not superfluous, matter), and now _more_ consistent, you take the opportunity to declare a problem?

      We could abandon the standard cosmology, but only if you provide a theory that predicts all it does and something more. MOND or MOND type GR modifications doesn’t do that, and in fact it has failed to predict most anything that the standard model does.

      NASA Pioneer 10/11 space probes.

      The Pioneer anomaly is explained by proper analysis of the probes thermal radiation. If you go to the paper, you see that the predictions now are consistent with the observations.

      • Anonymous says

        You contradict yourself. Current we need this mysterious dark matter for observations to match the theory. What Sol said is that if you base the theory on the observations, you don’t need to -add- dark matter to make things work.

        Dark matter is, after all, the stuff that is required to MAKE the theory match observation/experimental results.

      • WaxyMary says

        Ok, I’ll bite, provide a theory which can explain, in addition to these recent observations, ALL prior facts which are not in contention — in other words even those which currently support much of our standard model with DM as a part of the theory leading us to the standard model, which is, by your statement, a failed theory.

        Telling us we missed the point being made by Sol, which TL addressed correctly, is not providing us with much of anything testable.

        The observed data pulled from history along with careful study of all specific points over the years is what allows DM to remain a part of the current standard model. Please show how it (the standard model) is in error with those observations made and predictions as stated from results of testing the standard model. Exactly how DM does NOT fit, your words I think.

        While you are at this task please keep in mind the even greater need to explain what is pushing the universe apart; because whatever it is it seems to have a constant acceleration profile, in other words, dark energy is still needed. The term dark means we do not know much of anything about these two parts of the standard model. It does not mean they are just tossed into the model to make the observations fit the current model but rather the current model suggests these two types of matter and energy exist and all this determined from observation.

        Please enlighten us all, either Kernshala or Sol.

        Form the needed equation, make sure all that you state fits all observations, predict something NOT in evidence presently and show how only this changed or NEW theory accounts for all the observations to date and the prediction(s) made from the replacement theory you claim would explain the universe better (since it is simpler than the current model).

        That is how science works isn’t it?


      • Anonymous says

        I don’t have to prove anything. I’m just trying to get you to remember/realize that DARK MATTER is a fictitious substance used to make the current theories work. Dark Matter may be real … on the other hand, the currently accepted theories that rely on dark matter in order to match observations could be wrong.

        It is obvious from your post, however, that you fail to understand this and do not wish to even consider it. So much for the Scientific Method …

      • WaxyMary says

        Yes, you do have to prove — well, anything you claim is replacement for the current — ah, to the reaches beyond our kin with ya… I will not even ask you to explain how what I wrote gave you any impression the scientific method was to be discarded since you can not, the words are NOT there, the lines to read them between are not there either.

        You are sidestepping and you will continue to do so. Aside from this I hope your stepping leads you to where you are happiest and the company pleasant –converse, chat, what have you. Enjoy what you can of life and please, do it soon.


      • Anonymous says

        I’m very sorry, but I am having a great deal of trouble parsing your comment into common English.

        To answer the one mostly clear sentence on your first paragraph: What gave me the impression the Scientific Method was being discarded was your blatant disregard for the fact that “dark matter” is a filler value to make the existing, commonly accepted scientific theories match observed values and experimental evidence. If you think “dark matter” is a real substance because of this then you quite obviously do not understand HOW the Scientific Method works.

        I’m not side stepping anything. I’m stating that nobody on this planet knows for sure whether the fictitious substance commonly referred to as “dark matter” really exists or not. Or to phrase it another way — Show me the scientific evidence for the existence of “dark matter”? I’m sure you will claim that observations “prove” that dark matter must exist … and my counter argument, which you have so far failed to grasp, is that those same scientific observations could just as easily (and probably more likely) prove that there is a flaw in currently accepted theories and that a more accurate theory would not need to resort to “dark matter” to make theory match observation.

      • WaxyMary says

        I’ll make this as simple as you require. Try to follow along, here we go.

        Currently observations and measurements from a large number of variably different persons and methods are what give us the standard model. All of these observations are repeatable, measurable and coherent.

        Follow so far?

        From this you wish to subtract one of the ‘suggested (by observation and logic) unknowns’, and replace it with something _you_ can not name, have not posited yet and will never be able to describe, ever.

        Still with me?

        If I have I understood your non-reply correctly, then what you really are saying is ‘the Current Theory is FLAWED’, and have no other great or small additions to change this ‘flawed’ theory other than to say ‘YOUR (our) brains have FAILED, think of something else’, to add to the conversation. Have I condensed this soup you spewed into the conversation here correctly, if not tell me which word or words you need explained to you.

        Testing the current theory via the many and complex methods and measures, as has been done over the years, affords us a great deal of confidence in that theory. You would have us improve the “accuracy” of this theory so as to not need to insert or ‘resort’ to DM, DE, and I imagine any number of other unknowns in this complex system we casually refer to as the standard model. Please, suggest a more accurate way to deal with all the observations to, as you have said…

        “…those same scientific observations could just as easily (and probably more likely) prove that there is a flaw in currently accepted theories and that a more accurate theory would not need to resort to “dark matter” to make theory match observation.”

        Nice having you play but next time try to color with the crayons and put down the pinking shears. They do a poor job in what you are attempting to accomplish here. You are such a cut-up!


      • Torbjörn Larsson says

        DARK MATTER is a fictitious substance

        No, it isn’t.

        For comparison, a fictitious force, which nevertheless exists, is an apparent force that is used for convenience. (Appears from acceleration of the non-inertial reference frame, not from physical interaction on the observed object.)

        Dark matter does not only unequivocally exist according to standard cosmology and observations such as the Bullet cluster. It is real matter, not “apparent”.

        The thing is that it is noninteracting with EM. There is nothing uncommon in that, we know of lots of baryonic examples (say, non-luminous gas).

        It is obvious from your post, however, that you fail to understand this and do not wish to even consider it.

        Standard cosmology is precisely _about_ considering the reality of this and the wish to consider it by testing. It is you that tries to implicate problem with a successfully tested method, and can’t deliver a good enough alternative.

        For your benefit, the first rule of holes: when you are in one, stop digging. Put up or shut up.

      • RUBBISH!
        Dark Matter and or Dark Energy is the direct result of a gross misunderstanding of proper physics! And in particular glazed over a very important aspect of Physics which involves Energy constructs..

        Once proper Physics is applied and understood it will expose those advocates to dark matter and dark energy as frauds, who have NOT paid attention to the aforementioned details..

      • Consider this Mary,

        Our location is a Galaxy, and lets now consider we may be located beyond a theoretical event horizon to an observer located a considerable distance away from our Galaxy..

        Now lets postulate that our local distances to us remain constantly x amount of light years away from each other, but to an observer beyond our Galaxy, we are in fact – situated at some point.. and mind you this point seems to that observer is shrinking, and yet to us it seems beyond our galaxy the Universe presents as doing the opposite.. Mind you to us that’s an accelerating expansion! And Blow me down thats exactly what Red-Shift detections suggest!..

        Therefore it should be obvious to most well learned Physicists, that as portions of the Universe expands, then conservation laws must have other portions reciprocate and or experience compression and or the conversion of KE to PE compression points and or Black-Holes, Black holes that in fact are Blue-shifted regions of the Universe..

        One last thing, and that is if we consider the ratio of PE & KE to all respective mass and then sum PE & KE for each and every theoretical mass represented or modelled, including the mass that repulses all less kinetic mass around and towards each other, {Err~ commonly and incorrectly referred to as Space,}, all shackles to Physics will be eliminated!

        That’s right TOE has and will be confirmed as being resolved once the majority of Physicists clearly understand Basic Energy constructs and apply it correctly to theories involving “QM”..

        Energy Constructs provide a clear knowledge as to how KE is converted to PE and in doing so, The NEAR-Vacuum is the bases for relative Solids and or theoretical particles, that are repulsed around by surrounding relative NEAR-Vacuum.. yes folks Gravity is not some magical attraction, but rather the result of proper REPULSIVE force..

        Following is a two dimensional model as proof of concept..
        Let height represent “PE” and width represent “KE”..

        I want you to consider with the following model or form what would be the result if left and right inertia were allowed?


        By today’s current understanding the three relative solids located within a NEAR-Vacuum would attract each other and or coalesce, but the facts are that the relative solids are repulsed together by the highly Kinetic NEAR-Vacuum!..

        Put simply if one Does the maths properly! one has no need to refer to some unexplainable magical force such as attraction!..

        Cheers from,

      • Torbjörn Larsson says

        No, I don’t contradict myself, see my comment. Nor do you point out such a contradiction. What you try to inject, again, is an irrelevant complaint to a working theory: “you take the opportunity to declare a problem?”.

        Btw, are you saying someone named “Sol” is using several nyms?

      • Anonymous says

        Catching all the nonsense is proving a challenge.

  15. Torbjörn Larsson says

    LOL, the missing subject matter.

    They _do_ distinguish between search inside and outside the virial radius that Zwicky used. Tenuous, but the best link I can “predict” for now. (No possibility of confirmation – unless Plotner provides more data.)

  16. Anonymous says

    The fact that these filaments are now proven to contain baryonic matter has numerous ramifications in the fields of galaxy formation, supercluster formation and evolution, and indeed the formation and evolution of the universe itself. Previous research looking for WHIM naturally focused on superclusters as that is where you would expect to find it. I did not initally think that baryonic matter in isolated strands would be superheated. So there needs to some explanation for what sustains this heating process. Dark matter is the likely culprit. Another worthwhile question is whether these filmanets are a relic of the big bang and inflation or is dark energy playing a role in their formation? Not just good science, great science I would say.

    • WHIM is mostly fiction, more fiction than dark matter, let’s say.
      jimhenson hiding just another avatar isn’t going to change opinion.

      • Please explain this. Scientists stated “if we’re looking very very long distances from earth, we’re detecting mass, but if we’re looking closer to earth we only see about half the mass we’re expecting to see.” The mass settled into filaments extending between clusters of galaxies. (1) Wouldn’t this mean, that a LOT more mass was already out there at very very long distances, that they didn’t know about? (2) Since these filaments contain million degree ionized baryons in the Universe, wouldn’t electro-magnetic forces in plasma ALSO have both attractive and repulsive forces, and mess up the measurements believed by Dark Energy, and even reduce the amount from 74% dark energy to something substantially less? The scientists stated that MOST of the baryonic mass (gravity only) in the Universe is IN filaments. Galaxies and clusters align into walls and sheets along filaments that have a dark matter gravity component, so surely an EM component analogue is right there, too! WHY NOT GRAVITO-ELECTROMAGNETISM FOR A NEW THEORY OF THE UNIVERSE !!! Kip Thorne says the effects of relativity with frame dragging and spacetime warping rule the Universe, where they only whisper in our solar system. Gravity Probe B recently confirmed Gravito-Magnetism frame dragging exists, that warps spacetime. (3) If Dark energy is increasing redshifts and recession velocities of distant galaxies, and galaxies ARE NOW FOUND to be losing half their matter, enriching ionized heavy metals into the IGM, then wouldn’t a mere 4% visible matter cosmic expansion, that is solely based on light alpha hydrogen matter DE expansion, imply foolishness in making a determination for DE expansion of the Universe? (4) Could some of the DE “expansion effect” observed in galaxies, come from the depletion of metals (mass) in galaxies?

  17. Yeahyouright says

    My son and I don’t understand this (he’s eight, I’m 48)

  18. Sarah Collins White says

    Amelia, CONGRATULATIONS on your amazing discovery. As a fellow “undergraduate discoverer” I know what you must be going through. Great job, and the following diatribe is NOT directed at you.

    Now onto my rant for everyone else associated with this article…
    As a former Science Teacher, I have to protest to not only a professional scientist (Dr. Pimbblet) misusing a key scientific term, but a science based magazine erring as well!!!
    A “theory” is a scientifically accepted explanation of a phenomenon
    A “hypothesis” is a prediction
    To Dr. Pimbblet, Ms. Plotner, and the editor who let this article slip by… Shame on you for using theory instead of hypothesis! Science teachers have a hard enough time teaching our students the differences between the two, and that the word “theory” has a different meaning in science than it does in general conversation, but for you to misuse these terms is a huge error. How many school children do you think will be reading this because their teachers wanted to show them this amazing breakthrough. Now we as teachers are going to have to work even harder to clear up their confusion.

  19. Finding filaments by detecting the soft x-rays emitted, doesn’t mean that the “missing mass” has been found. Some of the missing mass has been found, but no way close to finding ALL of the mass in ALL of the filaments. Scientists have been detecting the WHIM filaments in the IGM and the Hot IGM before. Taotao Fang is the expert on the matter, and stated he looked right through a long filament connecting the sculptor wall of galaxies, with a blazer and huge black hole. Fang has stated BEFORE in the discovery last year, of this same missing baryonic mass, that these filaments are easy to see right through, and scientists look through them all the time. Their density is only about 6 protons per cubic meter, and temp is ~1 million degrees. They intertwine into knots, and pervade permeate the entire galaxy as a flowing plasma. The interpretation of these findings, is what this is all about, and in no way does it support the big-bang theory. There is NO DISPUTE that the WHIM and these huge plasma filaments ACCOUNT FOR MOST OF THE MASS OF THE UNIVERSE! Half the atomic matter in the universe could be in the WHIM. The WHIM is not at all fictional, as this discovery proves, and there is a LOT more filaments that new telescopes will be able to observe. New telescopes are already under construction and being built, so that we can directly observe cosmic filaments ! Until that time, plasma astrophysics remains in its youth.

  20. If we consider the Entire universe as a body of energy so that if it were a Near-Vacuum we would have a near zero potential with near maximum Kinetic energy, to which on compression to some of the Near-Vacuum and or via introducing opposing velocities, KE is converted to PE and or a Relative Solid..

    For example let height represent PE and width represent KE so that for a relative solid we may model the following “=” which if uncompressed would presents as a Relative Near Vacuum “–”
    as in minimum PE or height and maximum KE or width..

    Or to consider it the another way..

    —- here we have four units of energy and in order to convert KE “width” to PE “height” we need to have half of the model with maximum velocity “c” to the left and the other half to the Right @c
    the result is a relative near solid “=” in the midst “-=-” where the upper 2D body could be treated to be @c relative to the lower 2D body which is also @c but mind you in the opposite direction, in reality they are in fact enmeshed and so this new Potential presents with zero velocity and or this theoretical particle expresses zero charge.. as for the two outer trailing potentials, they now can be referred to as the relative solids reason for experiencing gravity, there is also one more thing and that is to model the following is in fact inaccurate “-=- as the relative solid in the midst should have been actually modelled as such “|” rather than as per the following “=”

    The reason I modelled it as such “=” was so that I could explain how KE is converted to PE..
    in reality..

    I now have a question based upon the following 2D model..

    if the above model were allowed to behave as per the laws of Physics via the 2 defined dimensions height and width or PE & KE.. what would occur to the three theoretical compression points applied by the highly kinetic mass surrounding them?
    You would be correct if you expressed the near vacuum would repulse them together and perhaps may even cause them to spin around the main compression point and or any other compression point, much like our moon does..

  21. Dark Energy and Dark Matter is good as phased out! These inferences only came about via the total lack of proper physical understanding..

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