New clues on dark matter from the darkest galaxies

A study by SISSA provides important information on its composition and on its interaction with luminous matter

Scuola Internazionale Superiore di Studi Avanzati

IMAGE: NASA/ESA Hubble Space Telescope image capturing UGC 477, a low surface brightness galaxy located just over 110 million light-years away in the constellation of Pisces (The Fish). Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt

IMAGE: NASA/ESA Hubble Space Telescope image capturing UGC 477, a low surface brightness galaxy located just over 110 million light-years away in the constellation of Pisces (The Fish). Credit: ESA/Hubble & NASA Acknowledgement: Judy Schmidt

They are called low-surface-brightness galaxies and it is thanks to them that important confirmations and new information have been obtained on one of the largest mysteries of the cosmos: dark matter. “We have found that disc galaxies can be represented by a universal relationship. In particular, in this study we analysed the so-called Low-Surface-Brightness (LSB) galaxies, a particular type of galaxy with a rotating disc called this way because they have a low-density brightness “says Chiara di Paolo, astrophysicist at SISSA and lead author of a study recently published in MNRAS together with Paolo Salucci (astrophysicist at SISSA) and Erkurt Adnan (Istanbul University).

The researchers analysed the speed at which the stars and gases that compose the galaxies subject matter of the study rotate, noting that the LSBs also have a very homogenous behaviour. This result consolidates several clues on the presence and behaviour of dark matter, opening up new scenarios on its interactions with bright matter.

Lights and shadows on matter

It is there but you cannot see it. Dark matter appears to account for approximately 90% of the mass of the Universe; it has effects that can be detected on the other objects present in the cosmos, and yet it cannot be observed directly because it does not emit light (at least for the way in which it has been searched for to date). One of the methods for studying it is that of rotation curves of the galaxies, systems that describe the trend of the speed of stars based on their distance from the centre of the galaxy. The variations observed are connected to the gravitational interactions due to the presence of stars and to the dark component of matter. Consequently, the rotation curves are a good way to have information on the dark matter based on its effects on what it is possible to observe. In particular, the analysis of the rotation curves can be conducted individually or on groups of galaxies that share similar characteristics according to the universal rotation curve (URC) method.

The novelty of the research lies in having applied the URC method for the first time, already used for other types of galaxies, to a large sample of low-surface-brightness galaxies, obtaining similar results. “We have compared rotation curves of various LSB galaxies finding that there is no discontinuity but gradual and ordered variations starting from the small to the large. Something similar was also observed for spiral galaxies,” explains Salucci, the other author of the study: “This method was applied for the first time in 1996, and to date it has shown that all disc, spiral, dwarf and now also the LSB galaxies can be represented by a universal relationship. This means that we are able to express an ordered trend through a formula which, keeping account of very few parameters, describes how dark matter and luminous matter are distributed”.

New possible scenarios

As it often happens in scientific research, the study has revealed further surprising and unexpected results. “We have discovered relationships of scale between the properties of the stellar disc and those of the dark matter halo, for example a relationship between the dimensions of the stellar discs and the dimensions of the internal region with a constant density of the dark matter halo” explains Chiara Di Paolo. “Furthermore, by comparing the relationships found in the LSB with those obtained in different types of galaxies, we have found that they are all almost coincidental. And it has been a great surprise to verify that galaxies with a very different morphology and history show the same relationships between the properties of dark matter and those of luminous matter”. This result, together with some specific features of LSB galaxies, opens up a new series of scenarios including that of the existence of another type of direct interaction, in addition to the gravitational one, between the two types of matter that form galaxies. A fascinating idea to be verified by new observations.

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From EurekAlert!

77 thoughts on “New clues on dark matter from the darkest galaxies

  1. What I don’t understand is how dark matter can be 90% of the universe, yet we can see all the other 10%. Wouldn’t the dark matter block it out?

      • Dark matter does not react with other matter , does not react with EM radiation : in short there is not evidence it exists at all except that it must be there otherwise our cosmology would be wrong. That is clearly not possible, so the answer is fairy dust we can’t detect.

        “… a constant density of the dark matter halo”

        A halo is a bright ring. They now have a bright ring of dark matter which does not emit any light and does not interact with light. Do they even realise what BS they are talking?

        Well, I’m sure all these cosmic cosmologists are getting paid handsomely for propping up a failing “consensus” orthodoxy.

    • It’s “dark”, as in completely invisible to light. It doesn’t interact with the Electro-Magnetic Force, and apparently the Weak and Strong either. It’s just perplexingly there, affecting gravity unevenly throughout the cosmos.

      There hasn’t been this bad of a head-scratcher since the late 1800’s and the hunt for the mysterious substance “helium”.

      • I always hunt for helium balloons at parties, and then inhale it before singing “We represent the lollipop guild” song from “The Wizard of Oz”.

      • The more I try to visualise and understand dark matter, the more amazed and dizzy I get. Here is this stuff (or is it stuff??) you cannot see – and yet it comprises 90% of all the matter in our universe. Responding to gravity, as does all the rest of matter (like us!!), it must end up in black holes – but then what?
        -How does it behave in there?
        -And what happens to it there, eventually?
        -Is it just pure energy?
        -How does it relate to, or interact with, neutrinos – and vice versa??
        -Is it neutrinos, in a weird way??
        -Does it also comprise 90% of Mother Earth – and 90% of little old me??

        Please, Mr Einstein – will you help me??.

        • Think of magnetic lines. You cannot see them but by their interaction with things we know they are there.

          • Could dark matter include Jupiter-sized objects not attached to solar systems? Or mini solar systems not massive enough for the “solar” part to light up?? Just asking . . .

          • Tom.

            Simple statement here.
            My self, since the further back I can recall,
            never able or capable to see the very air I breathed.
            No any chances I will ever be able or capable to ever see it.

            But still, I will never ever consider the air I breath as “dark matter”, mate.
            And still, I will accept that many there have the right to, whatever claim.

            Do you think you can see the air you breath?
            Will you in some given circumstance consider it as “dark matter”?

            cheers

          • Whiten,
            I did not make a claim about what dark matter is or isn’t.
            The question posed by Andy was :
            “The more I try to visualise and understand dark matter, the more amazed and dizzy I get. Here is this stuff (or is it stuff??) you cannot see ”

            I was simply using the magnetic lines as an example of things we cannot see but know they are there by how they interact with things.

            And remember that “dark matter” is just a term used for something that has an effect but that we cannot tell what it is that is causing that effect.

          • So we can prove dark matter existing by its interaction with visible matter? If it’s in the center of the galaxy, the outer stars would rotate fast but the inner stars, being closer to the gravity well, would rotate faster!
            Not happening.
            If dark matter was a halo around the galaxy, the other stars would be pulled towards it as would the inner stars creating a doughnut near the 90% of the matter. Not happening.
            People assume the galaxy works on the planetary model where the closer you are to the center star/mass, the faster the planets move. Like a Vortex. In reality, it’s more like a hurricane where wind speeds are greatest around the very calm and mild eye at the center.
            The entire spiral disk moves like a record where the inner stars move at the same velocity relative to the outer stars. It is consistent with the simple model that the fast moving outer stars are held in check by the combined mass of billions of stars at a right angle to its Momentum. The inner stars have equal gravitational pull to the billions of stars that surround it allowing it to have very little momentum or velocity. If a slower star was caught in a slingshot, such as a black hole, increasing its velocity, it will be thrown out of the center to a point at which the combined mass/gravity of the galaxy will pull it in balance giving it a new position relative to it’s mass like other stars moving at the same velocity.
            This is also the observed condition when two Galaxy’s moving past each other, which should have the momentum to continue the journey forever with very little interaction, are pulled towards each other converting their speed to circular/angler momentum combining the galaxies. This proves that the normal weak force of gravity is greatly intensified as observed on the galactic size/ scale. (Except for the quasar/ pulsar, with has the mass of entire galaxy in one star, are ejected from the now faster spinning galaxy and continue on their way)
            The only other explanation for dark matter and its lack of visibility or interaction is that it’s quantum in nature which means normal rules do not apply. Mass popping in and out of our existence then returning to where it is shared from. It can be categorized as subspace/ Black hole or worm holes connecting in a subatomic way, hyper space, dimensional space, ether, infinite universes or astral projection/fantasy realm.

          • Except that magnetic field lines are not there, any more than the contour lines or lines of latitude and longitude on a map will be found engraved on the ground.

          • Think of magnetic lines. You cannot see them but by their interaction with things we know they are there.

            No Tom, magnetic lines only exist in highschool note books to help explain magnetism. They do not “exist”. There are not “magnetic lines” in the real world. There are no lines around a bar magnet, not lines around the Earths poles, not lines around the Sun.

            I never saw evidence of a magnetic line interacting with anything, other than the human eye.

          • Greg,
            Yes, it would have been better if I had said magnetic fields rather than lines. I was just trying to paint a verbal picture to answer the original question.

    • If it has neither electric charge nor magnetic dipole moment, it wouldn’t interact with light in any strong way (i.e. absorption, emission, or scattering). If it has mass, however, it can bend light through gravitational lensing. That’s a weak interaction, and it has been observed.

    • You might want to look up the Neutrino, it is speculated by a lot of scientists that dark mater is a kind of heavy neutrino that has not been discovered/detected yet.

    • The vast, vast majority of space is empty, even with 90% of matter being dark matter.

      Think of it this way. The sun itself is less than a light second across. The entire solar system is a few light days across. The closest star to our sun is over 4 light YEARS away.

      Even if our solar system contained 10 times as much mass as it does, how much extra light would it block?

  2. “This result, together with some specific features of LSB galaxies, opens up a new series of scenarios including that of the existence of another type of direct interaction, in addition to the gravitational one, between the two types of matter that form galaxies.” I think electrical charge will be a logical candidate as a second type of direct interaction besides gravity; furthermore we do not know what gravity is, we know what it does..

    • The defining characteristic of dark matter is that it *doesn’t* interact with electromagnetism at all. At least with neutrinos, which also don’t, occasionally interact with matter when they collide with atomic nuclei. Dark matter seems not to do even that.

      • As far as we can tell, no. Atoms are held together by nuclear forces. Dark matter, however, seems to be wholly immune to the nuclear forces as we know them. As such, dark matter particles just keep loosely zipping around forever, or maybe until they fall into a black hole… maybe.

      • No.

        Dark matter appears not to interact with baryonic matter, except via gravity. Baryonic matter consists of the subatomic particles, atoms and compounds of observable chemistry and physics.

        Dark matters seems to exist in spherical halos, composed of hypothesized massive halo objects, ie MACHOs, around galaxies. Some astrophysicists have argued for WIMPs, particles forming disks around galaxies like those seen of baryonic matter particles, and weakly interacting with them.

      • Patrick, so called “dark matter” doesn’t fall into black holes

        – the other way round:

        Black holes, born baryonic, gather around: “dark matter”.

  3. Another explanation for the observations is that we don’t have a complete understanding of the force of gravity.

    • If gravity was simply misunderstood, that would make things so much simpler. Alas, while not entirely ruled out, that hypothesis has suffered greatly over the past year or so. It just doesn’t have a good explanation for the arbitrariness and lumpy distribution of gravity found in observations.

    • Jeff,

      Thanks for the link. If their theory is correct, all the Black Matter proponents would no longer need to be funded by government to “Study” the cosmos to “Find” black matter/energy.

      It is all about the money, and the nature of “MAN”. Once they are invested in an OPINION, they will fight for it to the end. The end, for taxpayers, is to END THE FUNDING.

      Theory, hypothisis, proof. If “science” fails this process, it should not be funded.

      And ALL government funded data MUST be required to be PUBLICLY archived for ALL to use. WE paid for it, not the so-called scienists like Mann.

        • Fudge and fairy dust, they just don’t fully understand how the two interact with each other yet !

          Thanks for that link Jeff. That makes a lot more sense. Occam rules.

          When you need to start hypothesising hole shells a invisible non detecatable dust around every galaxy, it should be a good clue that you are heading along a long dark path to nowhere.

      • Drake, I know where you’re coming from, but I can’t completely agree. In particular, funding for defense research should not necessarily be made public IMHO.

        On the other hand, Climate Science is trying to save all mankind, and not a jot nor tittle should be hidden from the public.

    • Really excellent link. Paper is open access.
      Kepler had nothing to offer his benefactor for New Year around 1611, so offered a story on Nothing.

      I just wonder, they mention the temperature of a galaxy, relate it to entropy. What about redshift?
      Have they an explanation for intrinsic redshift?

      Very interesting indeed…

  4. Remember to remain skeptical. If experiment (and/or observation) belies your theory then that theory is wrong (or at least inadequate). Thus far, despite a massive effort, the failure to “find” the dark side sounds hauntingly familiar…

  5. Anth*ny & mods — I like these articles. Keep ’em coming.

    This method was applied for the first time in 1996, and to date it has shown that all disc, spiral, dwarf and now also the LSB galaxies can be represented by a universal relationship.

    I notice they don’t mention elliptical galaxies, but that may be because rotation-rate is more difficult to determine in these galaxies.

    • Sure you invent a ring of fairy dust , adjust the parameters to fit and you can explain anything with your new “universal” rule.

      This is pretty much how climate models work, just on a galactic scale.

  6. Shakespeare had the best, and still valid, comment on such mysteries:

    “There are more things in heaven and earth, Horatio,
    Than are dreamt of in your philosophy.”
    – Hamlet (1.5.167-8), Hamlet to Horatio

  7. If gravity could exist independently of mass, as well as being a property of mass, would that explain all the observations?

    On a different front: why aren’t planetary orbits, and the orbits of multiple star systems perturbed by the gravitaional effects of all this dark matter?

  8. Measuring the effects on rotation etc. is precisely how they came up with dark matter! So there is nothing new to discover here. First thoughts should be on effects of gravity itself over large distances. Pioneer 1 and 11 in signals after leaving the solar system indicated stronger gravitational pull from the sun than calculated. Yeah, they came up with internal issues with heating in the satellite itself as a fairly unsatisfactory explanation because of the sanctity of gravitational law!

    Maybe, like an elastic band, the “bond” stiffens with great distance, something we can’t yet measure in solar system distances? Maybe their is a small correction needed with the existing law? Maybe? But to cement dark matter into the hypothesis eill only make us happy with another phlogiston theory for a couple of centuries.

    • I don’t believe measuring the effects on rotation is exactly how Kelvin came up with “dark matter.”

      Kelvin guesstimated that the stars in the Milky Way should not have been holding together so much, and rotating together so much. He developed a place-holder answer, or non-answer of sorts, by saying, in so many words, “there must be more mass there; we just cannot see it.”

      Since then, other measures have been consistent, and the dark matter idea has hung around to explain what we are observing. So, “Dark Matter” is a place-holder answer and we are trying to fill in that blank.

      • “… to explain”. I think you really mean to cling. It’s the modern way with science, although Max Planck opined that science advances one funeral at a time! So the observation has been around for about a century. We will get to reappraise Max’s insight with Dangerous Global Warming Science before long. It’s been thoroughly debunked and its dead body is being carried forward by activists with a alternative agenda for it.

  9. Maybe everything that gets ‘sucked’ into a black hole actually comes back out of it but in a higher dimensional state where it’s only interaction with our, physical, universe is as unobserved mass that has gravitational effect and nothing more.

    Cheers

    Max

  10. ‘Dark matter is on the move: Scientists find the material can be pushed out of a galaxy‘s center’
    (https://dentondaily.com/dark-matter-is-on-the-move-scientists-find-the-material-can-be-pushed-out-of-a-galaxys-center/)

    > “The dark matter at the centres of star-forming dwarfs appears to have been “heated up” and pushed out.”

    Dark matter is pushed out by the visible matter a galaxy consists of. The more quarks a galaxy contains the greater the dark matter is pushed out, the larger the dark matter halo associated with the galaxy.

  11. Check Sabine Hossenfelder on the subject of dark matter and the concurrent theory of modified gravity:
    https://www.youtube.com/watch?v=468cyBZ_cq4&list=PLwgQsqtH9H5c4IXKj82g-Kzbs0EXaq5T3&index=25

    Same thing about dark energy:
    https://www.youtube.com/watch?v=oqgKXQM8FpU&list=PLwgQsqtH9H5c4IXKj82g-Kzbs0EXaq5T3&index=1

    If you check her other videos you’ll find out she gives a fair description of all those different phenomenons and the evidences for or against them.

  12. So Dark Matter is 90% of the universe, but we can’t see it. Is there any evidence of something running into a big chunk of Dark Matter? Planets suddenly exploding, getting chunks knocked off, blasting through a star? Will this deny us travel to the stars until we can actually determine the location of these ubiquitous, but unseen stellar land mines? Personally, I don’t want to hop on a ship to Alpha Ceti IV if there is a risk we’re going to hit a chunk of Dark Matter. Because if we do, you will see some dark matter in my pants as well!

  13. While I’m not disputing the existence of either dark matter or dark energy they sure look like an ad hoc type of explanation for observations that don’t fit our standard theories. They remind me of the wheels within wheels inserted into pre-Copernican earth centric models of the solar systems. We should be cautious in accepting either dark matter or dark energy until we have some experimental proof that they actually exist or until all other explanations have been ruled out.

    It looks awfully convenient that dark matter forms halos outside of galaxies. If it feels gravity but isn’t pushed away by solar wind or light, why wouldn’t enormous amounts of dark matter fall into the sun and other stars and wouldn’t that throw off all our calculations about how stars behave?

    • You’re onto something there.
      Estimates of what galactic rotations “should be” are based on estimates of the galactic mass, and it doesn’t seem to jive with observations, ergo – there must be some other mass involved. They propose “dark matter.” Maybe it’s just the mass that has already crossed the event horizon of the central black hole, and they haven’t taken that into account….Or maybe it’s the one stray He atom in every 100 cu m of otherwise empty interstellar space?

  14. Here is some background on the subject of dark matter and spiral galaxy properties/formation.

    Dark matter the concept has been dead for at least a decade, as there are observations that it cannot explain and 40 years of searching has confirmed there is no dark matter particle based on the searches and the standard particle model.

    As noted below, there are spiral galaxy observations that require a mechanism that increases angular momentum with spiral galaxy mass (Disney’s paper Galaxies are simpler than expected). The concept dark matter does not have the ability to do that.

    The concept ‘dark’ matter was invented to try to provide an explanation for the fact the rotational speed of spiral galaxies (disc galaxies) is constant with increasing radial distance from the center of the spiral galaxy to the outer edge. What would be expected is the rotational speed should decrease with increasing distance for the spiral galaxy center.

    Rotational speed is of course directly related to the angular momentum of the spiral galaxies.

    The big bang theory produces angular momentum by random torque interactions of gas clouds. The angular momentum (Spin speed) of a spiral galaxy should therefore be random and limited.

    As this key paper by Disney shows for some unexplained reason spiral galaxies gain angular momentum as they get larger.

    As Disney notes in his and other’s paper, the big bang theory cannot produce the large amount of angular momentum observed in large spiral galaxies and cannot produce increasing angular momentum with increasing galaxy mass.

    http://arxiv.org/ftp/arxiv/papers/0811/0811.1554.pdf

    “Galaxies are Simpler than Expected
    Galaxies are complex systems the evolution of which apparently results from the interplay of dynamics, star formation, chemical enrichment, and feedback from supernova explosions and supermassive black holes1.
    The hierarchical theory of galaxy formation holds that galaxies are assembled from smaller pieces, through numerous mergers of cold dark matter2,3,4.

    The properties of an individual galaxy should be controlled by six independent parameters including mass, angular-momentum, baryon-fraction, age and size, as well as by the accidents of its recent haphazard merger history. Here we report that a sample of galaxies that were first detected through their neutral hydrogen radio-frequency emission, and are thus free of optical selection effects5, shows five independent correlations among six independent observables, despite having a ….

    … This implies that the structure of these galaxies must be controlled by a single parameter, although we cannot identify this parameter from our dataset. Such a degree of organization appears to be at odds with hierarchical galaxy formation, a central tenet of the cold dark matter paradigm in cosmology6.

    …Consider spin alone, which is thought to be the result of early tidal torquing. Simulations produce spins, independent of mass, with a log-normal distribution. Higher-spin discs naturally cannot contract as far; thus, to a much greater extent than for low-spin discs, their dynamics is controlled by their dark halos, so it is unexpected to see the nearly constant dynamical-mass/luminosity ratio that we and others14 actually observe.

    Heirarchical galaxy formation simply does not fit the constraints set by the correlation structure in the Equatorial Survey.. ”

    After a spiral galaxy has formed there is no mechanism in the big bang theory to add angular momentum.

    If two large spiral galaxies collide what is expected to form Is not a spiral galaxy but rather a spherical galaxy or at least a spiral galaxy with a large bulge in the center. This is not observed.

    The majority of galaxies which we can see in sufficient detail to determine galaxy type are spiral. What we would expect that with time there should be less and less spiral galaxies, do to collisions. This is not observed.

    There is in fact a vast class of bulgeless spiral galaxies including our own and Andromeda which have somehow grown to a massive size without producing a bulge around the center of the spiral galaxy or turning into an elliptical galaxies.

    http://arxiv.org/pdf/astro-ph/0702585v1.pdf
    THE MILKY WAY: AN EXCEPTIONALLY QUIET GALAXY; IMPLICATIONS FOR THE FORMATION OF SPIRAL GALAXIES
    Disk galaxies constitute the majority of the galaxy population observed in the local universe. They represent 70% of intermediate mass galaxies (stellar masses ranging from 3× 10^10 to 3 × 10^11 M⊙), which themselves include at least two-third of the present-day stellar mass (e.g., Hammer et al. 2005).

    We conclude that the standard scenario of secular evolution driven by the accretion of gas and disk instabilities is generally unable to reproduce the properties of most (if not all) spiral galaxies, which are well represented by M31. However, there are several outstanding difficulties with this standard scenario. One such difficulty is the so-called angular momentum problem.

    That is, simulated galaxies cannot reproduce the large angular momentum observed in nearby spiral galaxies (e.g., Steinmetz & Navarro 1999). Another is the assumed absence of collisions during and after the gas condensation process. Indeed, the hierarchical nature of CDM cosmology predicts that galaxies have assembled a significant fraction of their masses through collisions with other galaxies.

  15. I am expressing something here, which may not have any meaning at all in the end, but just in case.

    We have the best minds in cosmology still considering dark matter at an ever increasing hot hypothetical and theoretical, exotic supper duper approach, without telling any one concerned,
    that at the very best this happens to be supported, only in the consideration of the 3D universal model, when in a very cherry picking proposition dependence of it,
    where all happens to be relying in only something as at most in consideration of ~90 degrees of observational angle,which happens to be ~270 degree short of the full 360 degree 3D model, that these very “silly clever” guys actually rely and depend on…

    Technically, or some other way meaning,
    that there is no support thus far anyway, from the very 3D model, these “clever” guys rely on, in the rest and respect of the ~270 degree observations angle as per the very 3D model under consideration.
    3 parts out of 4, in the very meaning of their “own” 3D universal model, do not offer any support there anyhow and anyway to this “bill nayers”, in this further attempt on explaining of the “dark matter”

    It simply, from this angle, happens to be considered as only an extreme exploitation, extrapolation, which barely has some minimal support only within the factor of 1 versus 4, as per their “own” 3D universal models…

    Aka, only at best,
    25% consideration of merit there basically,
    and that still only so, due to the condition of the huge effort required when considering the prospect of a full 360 degree 3D evaluation of the universe there, as per the very model, in the very given consideration of this condition…

    But still;

    This later day attempt in explaining “dark matter”, still very much relying in a very very selective and narrow intended fully biased approach…
    cleverly sold out, to who ever ready and willing to bye there.

    Please be kind, and get the main claimed point put forward here;

    It simply states that the observation and data considered in the consideration of this latest day approach in “dark matter” explanation, it simply consist as not universal properly based,
    just only regional to a small part of the observed universe there as per the merit of the 3D universal model…
    not yet a universal condition to consider, still regional.
    and still only regionally utilized, selectively.

    Whether wrong or right, that happens to be the claim forwarded!

    Yes, of course, no “Dark Supernoveas” yet there! 🙂

    cheers

  16. “Gravitational waves are disturbances in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light.”
    LIGO instruments observed number of gravitational waves while Weiss, Thorne and Barish got 2017 the Nobel Prize for it, therefore we have to take it that gravity propagates at speed of light, and as such it has to be subject to the laws of theory of relativity. When the rules of relativity and wave theories are applied to gravity as in this
    link
    conclusion is that there is no requirement for ‘dark matter’ and the ‘dark energy’ is nothing more than the energy which may be contained within gravitational wave field.

  17. My dad always used to say that a good engineer was somebody who could do for a dime what any idiot could do for a buck . (My corollary is “… and the government can do for a Benjamin, maybe, on a good day.”)
    If this article interested you, check out the Dragonfly telescope developed by Peter Van Dokkum of Yale and Roberto Abraham of U. Toronto. They designed an instrument specifically to look for low-brightness galaxies using essentially off-the-shelf telephoto lenses. The key is minimizing scattered light. Big scopes collect a lot of light, but they aren’t sensitive to dim extended objects because of the galactic background of scattered light. Here’s a good general explainer:

    https://jgroub.wordpress.com/2017/04/15/april-14-2017-the-dragonfly-telephoto-array-galactic-formation-and-dark-matter/

    For half a million bucks, van Dokkum and Abraham blew the doors off the big boys!
    https://arxiv.org/pdf/1401.5473.pdf and http://www.dunlap.utoronto.ca/instrumentation/dragonfly/
    (the Dragonfly now has 48 telephoto lenses instead of the 8 in the first paper).

    I think this is conceptually brilliant science. So does Freeman Dyson:
    https://www.edge.org/response-detail/26738

  18. Dark matter seems to be a “fudge factor” to make sure that the centers of galaxies have enough mass to exert the gravitational force needed to keep the outer stars of the galaxies in a stable orbit.

    But the orbital velocities of the outer stars of distant galaxies are deduced from the red- or blue-shift of their spectra relative an assumed spectrum for a low-velocity star (such as the sun). Assuming these velocities are correct, then the mass of the stars near the center have to be estimated from their diameters, with an assumed value for their density. But what if the density of the central stars is much higher than that assumed for them–then “dark matter” may not be necessary to provide enough central mass to keep the outer stars in orbit. Do we really know the density of distant stars accurately?

    It is also possible that these distant galaxies contain other small stars which are not necessarily dark, but are too small to be detected by our best telescopes at their distance from Earth. Perhaps if we were closer to the center of the distant galaxy, we would see those stars, and dark matter would not be necessary to close the “gravity balance”.

    Also, it is possible that some of these distant galaxies have a black hole at the center, which is so massive that even light cannot escape its gravitational field. We cannot therefore “see” a black hole with visible light, and it can only be detected by the effects of its gravity on neighboring objects far enough away so that their light can reach us. Is it possible that “dark matter” consists of black holes at the center of some galaxies?

    The main reason for conjecturing the existence of “dark matter” is lack of enough information about distant galaxies to close the “gravity balance” (finding enough mass to hold the galaxy in orbit around the center). Dark matter is merely mass we cannot see, either because it is in a black hole, or its light is too weak to be detected from Earth or satellites in Earth orbit.

  19. “One of the methods for studying it is that of rotation curves of the galaxies, systems that describe the trend of the speed of stars based on their distance from the centre of the galaxy. The variations observed are connected to the gravitational interactions due to the presence of stars and to the dark component of matter. ”

    Um… is it just me?

    The rotation peculiarities of galactic disks was WHY they invented Dark Matter and now they are using those peculiarities to explain DM?

    Shouldn’t they be looking for actual evidence rather than circular reasoning?

    • Yep, but they are very intelligent so it is better termed as torusional reasoning.

      (Mobiussinal is reserved for the politicians)

    • MarkMcD – very good point. And am I alone in thinking that Einstein’s explanation of gravity – curved space – was no explanation at all? It seems to me that if only they could work out the mechanism of gravity they might do a lot better.

      • There’s a guy by name, Reg Cahill, from Adelaide Uni. He shows that Michelson-Morley actually DID get a result as did those who tried to duplicate the M-M and explains why.
        http://www.mountainman.com.au/process_physics/hps09.pdf

        Another point of failure is James Clerk Maxwell’s original book and formulae. Far from what we were taught about the mechanics of EM, Maxwell wrote in quaternions, 4 dimensional equations, subsequently truncated by Oliver Heaviside and Heinrich Hertz into vector equations, losing 2 forces along the way.

        And all our physics is based on tyhose truncated equations. At least 2 researchers used those 2 missing forces, Tesla and Thomas Townsend Brown to produce effects we still don’t understand. IIRC they are electrostatic (as a force, not an effect) and electrogravitic. TTB made things fly with no motor or fuel.

        M-M finding a result would mean there’s an Aether, (active ether) instead of the dead and unresponsive one in Einstein’s universe. So we do not need all these ‘force particles’ and Einstein’s Relativity becomes in need of radical rethink.

        And Einsteinian gravity doesn’t, as I understand it, and can’t exist so we need a rethink there as well. (which might allow us an explanation for things like how gravity lensing – e.g. around the Sun – is ONLY present out to the edge of the corona)

        Then we add in the 3 magics, Inflation, Dark Matter and Dark Energy, all solely defined as being just what is needed to make the Big Bang theory produce the observed universe .

        We need to go back to the 1800’s level and start over and come up with a physics that provides a SMP and SMC (Standard Model of Particles and Cosmology) That matches the real universe and not the fantasy one that is so complicating physics.

  20. “The researchers analysed the speed at which the stars and gases that compose the galaxies subject matter of the study rotate, noting that the LSBs also have a very homogenous behaviour.”
    ============
    Measured the speed ?, no mention of “time” ?

  21. We are told that there isn’t any dark matter around here. It’s all over there. But we can’t see it because it doesn’t interact with anything that affects what we see or how we see it. But it does affect gravity a bit. Seems to me that we could very easily be surrounded and/or occupied by dark matter – we don’t appear to have any method of detecting it if or when it’s nearby.

  22. Once mainstream science accepts that photons have real mass and multiple real spins and are attracted to matter there is no need for the dark matter/energy fudge. Physics needs to get back to the real world of hard knocks and forget the magical mathematical models.

  23. The science of “dark matter” is even more stupid than “climate science”. Of course there is a direct correlation of visible matter and “dark matter”. In fact dark matter is just where visible matter is.

    It all reminds me of a prominent crime case a few years ago which I could solve instantly by logical reasoning, and possible I should have informed authorities, though they might not have listened. They were searching for a female “Phantom serial killer” which left her DNA on a huge number of crime scenes, ranging from cop-kills to home invasions, to quite trivial burglaries. It turned out, the female owning that DNA was actually involved in the production of the cotton buds used to take the DNA..

    https://en.wikipedia.org/wiki/Phantom_of_Heilbronn

    The “dark matter” is strictly correlated to visible, or rather real matter, because what they observe is a function of real matter. Real matter, as opposed to fictuous “dark matter” has an effect on space-time and drags space along with it. This is even a well known phenomenon with regard to black holes, where neighboring space will be rotating according to the black holes own rotation.

    Since black holes are so massive, they are dominating neighboring matter in defining space-time. The closer you get to the black hole, the stronger that domination and the faster space will rotate.

    Of course the same is true for galaxies, although due to their size (relative to tiny and compact black holes) their effects on space-time are much more subtle, blurred and much harder to detect. Yet, with space rotating with the galaxy, this dramatically reduces centrifugal forces.

    So the basic mistake here is to take centrifugal forces as given and try to match gravity to it, by means of adding additional matter, in this case “dark matter”. While in reality gravity is just fine, but you need to reconsider centrifugal forces..

  24. My two cents:
    Quantum mechanics does well on the atomic scale, Newtonian mechanics on the planetary scale, and Dark mechanics on the grand scale of galaxies…We simply have not invented the Dark mechanics part. I doubt there is actually any “dark” matter at all.

  25. Dark matter and dark energy are postulated because physicists may not be open to considering a fifth fundamental force weaker than gravity, but operating over longer distances. Think about the increasing distances over which the four fundamental forces operate; using Occam’s razor, postulate a fifth fundamental force; and then develop its theory and equations which would allow for some predictions that would be substantiated by experimental measurements.

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