Dark Matter Doesn't Exist

Cosmology's collective delusion

The current cosmological model only works by postulating the existence of dark matter – a substance that has never been detected, but that is supposed to constitute approximately 25% of all the universe. But a simple test suggests that dark matter does not in fact exist. If it did, we would expect lighter galaxies orbiting heavier ones to be slowed down by dark matter particles, but we detect no such slow-down. A host of other observational tests support the conclusion: dark matter is not there. The implications of this are nothing short of a revision of Einstein’s theory of gravitation. Why the scientific community is in denial about the falsification of the dark matter model is a question that requires both a sociological and philosophical explanation, argues Pavel Kroupa.   


Astronomers and physicists today understand the observed Universe in terms of a model universe in which the normal matter we see around us in the form of atoms makes up only 5% of all the energy in it. About 20% is made up of exotic dark matter particles and about 75% is made up of even more exotic dark energy. This dark-matter-based model (for each gram of normal matter there are 25 grams of the exotic dark matter) is about 20 years old, but the strong belief in the scientific community that dark matter exists goes back 30 years.


There is a simple test that these scientists are ignoring and which has already been applied and it tells us that dark matter does not exist.


The many searches worldwide for evidence of dark matter particles, going on since at least 30 years, have come up empty handed, and yet today the scientists are even more convinced that dark matter rules the Universe. This dark matter can be extremely light weight "fuzzy" particles that are extended over thousands of light years, or it may be made up of particles that are heavier, such as "weakly interacting massive particles" (WIMPS), or even primordial black holes that formed from exotic physical processes during the Big Bang. The theory of dark matter makes no predictions as to what the particles ought to be and what to look for, and so a very large number of scientists searching for it with laboratories and experiments deep under ground, in the polar regions or in space and in all countries try to prove the existence of dark matter particles and to get the Nobel Prize. Many tens of millions of tax-payer dollars are being used up each year on this search.

22 04 27 Most complex thing.dc SUGGESTED READING The most complex thing in the universe By Marina Cortês But there is a simple test that these scientists are ignoring and which has already been applied and it tells us that dark matter does not exist. This test goes back to Subrahmanyan Chandrasekhar who, in 1943, showed that a massive body (e.g. a dwarf galaxy) that moves through a background of comparatively low mass particles (e.g. dark matter particles), will slow down. This process of "Chandrasekhar dynamical friction" is exceedingly well understood. It is the same physical mechanism by which our space craft are slingshot to the distant realms of the Solar System, by them first passing close-by a planet (e.g. Venus) in the inner Solar System, the planet slowing down a tiny little bit after the encounter, while the comparatively light-weight probe gets catapulted away, e.g. towards Pluto. A satellite galaxy slingshots myriads of dark matter particles to more distant regions around the major galaxy and so slows down and sinks towards the major galaxy to merge with it.


The galaxies behave as if they were naked, i.e., as if they did not possess the huge and massive haloes of dark matter particles which the theory predicts to be there.


With my collaborators and students, we have applied a number of observed galaxy systems to the calculations of Chandrasekhar dynamical friction we would expect to see if dark matter existed, and in all and every case it turns out that the slow-down is not in the data. We have studied the motions of the satellite galaxies around our own Milky Way at distances of a hundred thousand light years, the motions of galaxies a few million light years away relative to each other, and we also checked how quickly the bars of spiral galaxies rotate, and none of these systems show evidence for dark matter particles. The galaxies behave as if they were naked, i.e., as if they did not possess the huge and massive haloes of dark matter particles which the theory predicts to be there. Rather than observing the slow down of galaxies through Chandrasekhar dynamical friction, we observed a speed-up as the galaxies fall towards each other. This is the same as two stars that fall towards each other in a star cluster. They get faster until they pass each other and then they recede again from each other.

galaxy min SUGGESTED READING Escaping cosmology’s failing paradigm By Bjørn Ekeberg We established this in a number of scientific research publications over the past decade [e.g. 1,2]. The implications of these findings are that the dark-matter-based models of the universe are not valid descriptions of the real Universe. Without dark matter, the current cosmological model breaks-down. Since the model rests on Einsteinian gravitation to be valid, it also means that we need to find a different theory of gravitation. But this would change the whole dynamics of the universe, its expansion rate and with dark matter having been rigorously falsified to exist, it also becomes senseless to consider dark energy as being relevant.

The implications for theoretical physics are immense, and it is therefore necessary to double, to triple, and even to quadruple check if the falsification of dark matter is truly correct. In fact, dark matter models of galaxy formation and evolution have already been falsified in 2012 [3]. A particularly strong reason to reject the dark-matter models is through the observation that satellite galaxies are typically orbiting their host galaxies in vast disks of satellites, much like the planets orbit the Sun in one plane, while according to the dark matter models, they should be orbiting in all possible directions [4,5].


Without dark matter, the current cosmological model breaks-down. Since the model rests on Einsteinian gravitation to be valid, it also means that we need to find a different theory of gravitation.


So the above mentioned newer tests merely confirm the rejection of the dark matter models, with overwhelming confidence. Still, to be completely and totally sure that dark-matter-based models do not account for the real Universe, further tests have been made. This is necessary, also because the research community has largely ignored these falsifications, has been awarding itself many important research prizes on work on dark matter, and has even been quite actively trying to discourage young researchers to follow-up on the implications, while at the same time proposals for research money to study the most successful alternative, Milgromian gravitation (MOND), are being largely turned down.

Three other very major tests of the dark-matter based models have been published recently:

(A) One test relies on how rapidly a dark-matter-filled universe can form extremely massive clusters of galaxies that also penetrate each other. The El Gordo galaxy cluster is immensely heavy, weighing a thousand times the mass of the Milky Way and Andromeda together. This cluster is actually composed of two such clusters which have formed and transgressed through each other at a time when the Universe was only half its present age. It turns out that the dark-matter-based models cannot, under any circumstances, grow such massive clusters and also have them falling through each other by that time, falsifying the dark-matter based models rigorously [6].

(B) Astronomers have also discovered that the local Universe expands more rapidly than the distant Universe. This problem, known as the "Hubble Tension", has triggered many concurrent conferences and hugely long texts written by hundreds of scientists in which all possible solutions are being discussed and explained. Very exotic dark-matter-based models are being developed, with additional processes being speculated to act on dark matter (e.g. dark matter could be decaying, there could be dark photons) or that dark energy has some complex time behaviour or multiple dark forms. Impressive is that this vast expert community, that includes or is driven by major-prize-winning scientists, is entirely ignoring the obvious solution to the Hubble Tension: we are in a region spanning more than a billion lightyears across which contains fewer galaxies by about a factor of two than should be there. Galaxies in this void fall towards its sides (like apples falling to the ground) which is why we witness an apparently faster expanding Local Universe. While this "KBC Void" naturally accounts for the Hubble Tension, the KBC Void is entirely incompatible with the dark-matter-based models because these constitute a model universe which is homogeneous and isotropic on scales larger than a few dozen million lightyears [7].

(C) Another test of the dark matter models is to compare the thickness of galaxies with those observed in the real Universe in which more than 90 per cent of all galaxies are very thin spiral, or disk, galaxies. In the dark matter models galaxies grow over time mostly by merging with other galaxies. These galaxy-crashes typically destroy the thin disks. Our sophisticated analysis of thousands of observed galaxies show the dark matter based models to be totally incompatible with the real Universe, as the model produces galaxies that are typically too roundish compared to the profusive thin disk galaxies in the real Universe [8]. Other problems between the real Universe and the dark-matter models include massive galaxies to have been observed at an early time at which they should not yet exist [9], that modern observations tell us there to be dust between galaxies which challenges the interpretation of the cosmic microwave back ground as being the photosphere of the Hot Big Bang [10] and that the cosmic microwave background has features in it that are incompatible with an inflationary origin, suggest that the Universe is structured on all scales [11] (like a fractal perhaps) such that it may be understandable in terms of dust emission rather than a Hot Big Bang.


We need to scientifically understand why the dark-matter based model, being the most falsified physical theory in the history of humankind, continues to be religiously believed to be true by the vast majority of the modern, highly-educated scientists.


Three implications arise from the above:

(a) Modern cosmological theory is totally wrong and we need to develop a new theory based on MOND. MOND is a modern non-relativistic theory of gravitation which extends that of Newton by incorporating data from galaxies which were neither available to Newton nor to Einstein, both of whom had to base their deductions on data limited to the Solar System only. All predictions made 40 years ago by Mordehai Milgrom in the foundation papers [12,13,14] have been verified, and in Prague and Bonn we (with Nils Wittenburg and Nick Samaras) are now performing the first ever full cosmological calculations with star formation of a MOND universe. MOND comes from a simple space-time scale symmetry [15] and may be a consequence of the quantum vacuum [16], opening a possible path towards unifying gravitation with standard-model particle physics. A major recent review for further in-depth reading has just been published [17].

(b) We need to scientifically understand why the dark-matter based model, being the most falsified physical theory in the history of humankind, continues to be religiously believed to be true by the vast majority of the modern, highly-educated scientists. This is a problem for the sociological and philosophical sciences and suggests a breakdown of the scientific method [18].

(c) What role does the modern fixation on prize-money, awards and rewards play in the unparalleled stagnation of physics? Does the modern homo-cosmologicus only want prizes and awards, rather than to advance our understanding of the physical cosmos?



[1] "Galaxies as simple dynamical systems: observational data disfavor dark matter and stochastic star formation" Kroupa, P., 2015CaJPh..93..169K

[2] "Fast galaxy bars continue to challenge standard cosmology" Roshan, M. et al., 2021MNRAS.508..926R

[3] "The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology" Kroupa, P., 2012PASA...29..395K

[4] "Phase-Space Correlations among Systems of Satellite Galaxies" Pawlowski, M., 2021Galax...9...66P

[5] "Are Disks of Satellites Comprised of Tidal Dwarf Galaxies?" Bilek, M., et al., 2021Galax...9..100B

[6] "A massive blow for ΛCDM - the high redshift, mass, and collision velocity of the interacting galaxy cluster El Gordo contradicts concordance cosmology" Asencio, E. et al., 2021MNRAS.500.5249A

[7] "The KBC void and Hubble tension contradict ΛCDM on a Gpc scale - Milgromian dynamics as a possible solution" Haslbauer, M. et al., 2020MNRAS.499.2845H

[8] "The High Fraction of Thin Disk Galaxies Continues to Challenge ΛCDM Cosmology" Haslbauer, M., et al., 2022ApJ...925..183H

[9] "The Impossibly Early Galaxy Problem" Steinhardt, C.L., et al., 2016ApJ...824...21S

[10] "Universe opacity and CMB" Vavrycuk, V., 2018MNRAS.478..283V

[11] "CMB anomalies after Planck" Schwarz, D., et al., 2016CQGra..33r4001S

[12] "A modification of the Newtonian dynamics as a possible alternative to the hidden mass hypothesis." Milgrom, M., 1983ApJ...270..365M

[13] "A modification of the Newtonian dynamics - Implications for galaxies." Milgrom, M., 1983ApJ...270..371M

[14] "A modification of the newtonian dynamics : implications for galaxy systems." Milgrom, M., 1983ApJ...270..384M

[15] "The Mond Limit from Spacetime Scale Invariance" Milgrom, M., 2009ApJ...698.1630M

[16] "The modified dynamics as a vacuum effect" Milgrom, M., 1999PhLA..253..273M

[17] "From Galactic Bars to the Hubble Tension: Weighing Up the Astrophysical Evidence for Milgromian Gravity" Banik, I. and Zhao, H.S., 2022Symm...14.1331B

[18] "A Philosophical Approach to MOND: Assessing the Milgromian Research Program in Cosmology" Merritt, D., 2020, Cambridge University Press, ISBN: 9781108492690, 2020


Latest Releases
Join the conversation

Konstantin Pavlovich 22 October 2023

Dark matter, dark energy, the big bang and other inventions are the grossest mistakes of cosmologists. Such elementary mistakes made by these so-called "cosmologists" are not permissible even for middle school students of the most mediocre school. These errors are analyzed in detail on a solid foundation of physical laws (without any scientific delusional fantasies of cosmologists) in the book "Big Bang of Scientific Idiocy", author Pavlovich Konstantin. The book can be downloaded from аmаzon for 10 days for free.

Bud Rapanault 25 July 2022

@Roy Lofquist

I don't believe there is any historical evidence that the precession anomaly was a motivating factor behind the development of General Relativity. Rather, beyond the obvious desire to establish a principle of general relativity - that the laws of physics apply in any reference frame, it is well documented that Einstein considered the primary goal of GR to be the unification of gravity and inertia:

It is also worth keeping in mind that the field equations of GR have never functioned well at the scale of galaxies and above without the ad hoc additions of dark matter and dark energy.

Roy Lofquist 20 July 2022

@Bud Rapanault

A 38 arcsecond anomaly in the precession of the orbit of Mercury led to General Relativity.

Bud Rapanault 17 July 2022

@ Mark B, People who propose and publish strong statements with cosmological implications based on a set of flimsy data points regarding the dynamics of 5 pairs of widely separated stars, that they then couple to some speculative physics, aren't practicing science, they are engaging in mathematicism.

Mark B 15 July 2022

What do people think of this?

--- Testing Newton/GR, MoND and quantised inertia on wide binaries ---

M. E. McCulloch & J. H. Lucio
Astrophysics and Space Science volume 364, Article number: 121 (2019) Cite this article

5076 Accesses
2 Citations
75 Altmetric
Metrics details
Wide binary stars are within the low-acceleration regime in which galactic rotation curves deviate from Newtonian or general relativistic predictions. It has recently been observed that their rotation rates are similarly anomalous in a way that dark matter cannot explain, since it must be smooth on these small scales to fit galaxy rotation curves. Here, it is shown that Newtonian/GR models cannot predict these wide binaries since dark matter cannot be applied. It is also shown that MoND cannot predict these systems. However, a model which assumes that inertia is due to Unruh radiation made inhomogeneous in space by relativistic horizons (QI, quantised inertia) can predict these wide binaries, and it has the advantage of not needing an adjustable parameter.

Mario Ljubičić 14 July 2022

MOND is abstract - it might predict gravity with distance but what is the physical interpretation of this separation from Newtonian gravity?
The problem with all these hypotheses and theories (GR included) is abstract treatment of space and lack of relativity (GR is not completely relative).
And while dark matter doesn't work as proposed, exotic particles could still form an interpretation of observable phenomena.
If anyone is interested in a solution that works in all cases, check my Complete Relativity theory on amenoum org.

Kevin McBride 14 July 2022

Hi there.
I'm an accomplished research scientist and faculty in another field but I have a dispassionate interest in cosmology. I love science and cosmology was always a favorite of mine. The career in science went into a different field but i've always had a passing interest. A couple of observations from your article Pavel.

1) You do a great job of pointing out the short comings of dark energy hypothesis and the problems with current thinking of the field. The models don't work (but that is an exciting thing.... see my comments below)
2) You do a terrible job of self-evalution on the MOND hypothesis. Even an out of the field "amateur cosmologist" scientist like myself knows and can point out studies where MOND has shortcomings and issues with describing observational data. Look I get it, you think MOND is a better fit but as a fellow scientist be careful about putting aside critical analysis of your own hypothesis. Please reevaluate some of the wording in this article and how it fits with the philosophy of science i.e. "does not in fact exist", "overwhelming confidence" and "most falsified physical theory" (see below my comment about theory)
3) Accusing colleagues in the field of "continues to be religiously believed to be true by the vast majority of the modern, highly-educated scientists". that's pretty insulting. Most physicist I've interacted with don't "religiously believe" the current dark matter model, they are looking to modifiy hypothesis because they know it doesn't fit. Frankly none of the hypothesis completely fit and NONE reach the level of theory, including MOND. Religious comment implies "faith" e.g. belief without fact. We have plenty of "religious" zealots denigrating science and policy made with science in mind. Let's be thoughtful of how we use that word. Science is under attack politically all over the world. Last thing we need is accomplished scientists feeding that fire.

4) A theory in science is a totally different thing than a hypothesis. MOND and dark matter are models. They don't reach the level of theory, they are at best hypothesis. I really have an issue with scientists who don't clarify the basic philosophy of scientific methods to the masses and ones that don't make that distinction. Please everyone stop calling these things theory, you're using it as common venacular definition which people get confused about. Are you a scientist? use the word theory correctly.
5) Its pretty clear the dark energy models stink, MOND solves many of the observational issues dark energy has, but then has it's own issues. The scientific field has alot of issues with upturning dogma. "Paradigm" is overused but when its real is often met with resistance. The journal publishing models suck but there aren't really better ones that are practical. Scientific progress is as much about big headed egos as it is facts and data. We just realized we don't know diddly squat about how cosmology operates. Its exciting and gives importance to the field, outside of the field people take interest, that feeds progress. Embrace it, don't denigrate it. advocate for MOND don't denigrate fellow scientist. Politicians and the public are already doing that plenty enough, especially in an era where science probably matters to the common good more than ever in history. Stand up for science, the philosophy of it and your colleagues, even if you don't agree on specifics.
6) From a rather dispassionate distance without deep knowledge, MOND model seems to carry more weight. But I've experienced hypothesis being disproved by data, multiple times and that's usually the most exciting science I've done. Are we in this field because our ego demands we win ever time or because we love science?
7) Loved the discussion on why dark matter models are bad. Hated how you put down your colleagues that are working in that area

Joe Bakhos 14 July 2022

I very much agree with Dr. Kroupa's position. I've recently put forward a modified gravity hypothesis that explains galactic rotation rates and also cosmological expansion without the need of dark matter or dark energy. I am wondering if these methods might be used to prove or disprove the hypothesis I have put forward?

This hypothesis also includes an adaptation of general relativity that explains time dilation and energy increase at relativistic velocities and within a gravity well, while retaining Euclidean space.

Part of this hypothesis includes the idea that higher concentrations of neutrinos may inhibit other quantum processes. I am wondering if there is any theoretical basis for this claim that I am making?

Please take a look at my paper and comment if you wish.

A copy may be downloaded here at Vixra. Go to the Vixra site, and search for "Chasing Oumuamua" in quotes, and look for the paper by Bakhos

Carl Perizzolo 13 July 2022

I guess I'm stupid, but I've always had 2 simple explanations for the "expansion of the universe."
First, if you postulate the big bang was like a large shockwave, the universe is growing like a balloon. If you put 3 marks on a balloon, 2 next to each other and one on the opposite side, as the balloon expands it would appear that the far point is moving faster than the near one, but that is due to relative motion, not the absolute motion of moving away from a common center. The expansion is constant.
2nd option is the obvious one that the farther away a galaxy is the older it is. Therefore the farther back in time. So, the galaxies were moving faster a billion year ago than they are now, since the more closer / recent ones are moving more slowly.
One implies a constant rate of expansion, and one that's slowing down.

K Mitchell 13 July 2022

Plasma theory looks best, imo. Fits evidence. MUCH older universe - trillions of yo.

Many failed theories still in vogue, not least is CAGW, Big Bung, and mRNA vaxxes.
Let's put Dark Matter in the ground where it belongs, then we can drop these other failed and sometimes dangerous theories.

Jim Fisher 13 July 2022

It has seemed to me for some time that the idea of dark matter came about because those responsible failed to be scientific. It's as basic as that. The scientific approach, as any schoolchild can tell you, is that if you find your theory does not fit the facts, then you change the theory. In this case the so-called scientists have taken the opposite approach, keeping the theory and inventing some facts without evidence (dark matter and dark energy) to bring about the desired match.

Roy Lofquist 13 July 2022

Radio astronomy observations of Pulsars indicate that the Hubble Red Shift is caused by “Tired Light” rather than the expansion of the universe.

When Hubble published his observations of red shifted light from distant objects there were two possible explanations that came to the fore. One, originated by Georges Lemaitre, was that the Universe was expanding. The other, from Fritz Zwicky, was that light lost energy as it traveled, termed "tired light". At that time, ca. 1930, interstellar and intergalactic space were assumed to be perfect vacuums and thus there was no mechanism to redden the light. Now, 90 years later, we have actual observational evidence that Zwicky was right.

In the radio astronomy of Pulsars we find that the shorter wavelengths of the leading edge of the pulse arrive before longer wavelengths. The velocity of light, c, is NOT constant but varies by wavelength. The dispersion is proportional to the distance from us of the pulsar. The observed effect is isotropic. The conventional explanation is that the dispersion measure is the “integrated column density of free electrons between an observer and a pulsar”. The mechanism matters not. What matters is that the interstellar medium is not a vacuum but rather affects light waves in a way best described as having an Index of Refraction greater than 1, unity. We find the same phenomenon in the observation of Fast Radio Bursts from other galaxies, thus indicating that the intergalactic media is not an electromagnetic vacuum.

Bud Rapanault 13 July 2022

"Modern cosmological theory is totally wrong and we need to develop a new theory based on MOND."

Well, yes and no. Yes to the first part, the theory is totally wrong, but yes/no to the second. We need a new theory to be sure but if it is solely based on MOND while maintaining the erroneous foundational assumptions of the standard model, the result will be a model that is wrong in a new and possibly exciting (for some) way - but still wrong. There are two foundational assumptions of the standard model dating back to the early 20th century:

The first is the assumption present in the FLRW model that underlies the standard model, that the Cosmos is a unified, coherent, simultaneous entity that can be modeled with a gravitational model derived in the context of the the solar system, General Relativity. Given the observed scale of the Cosmos is @10 billion lightyears in radius and given the fact that the maximum speed of light is @3x10^8 meters/second, there is no possibility of the Cosmos we observe being a simultaneously existing entity. Another way of saying this is that there is no physical possibility of a universal spacetime frame having any physical meaning. That fact is consistent with General Relativity which does not have a universal frame but only describes the relativistic relationship between local frames. Solving GR for a model with a universal frame was an oxymoronic exercise and the result speaks for itself.

The second foundational assumption is that the cosmological redshift is caused by some form of recessional velocity. There is no empirical evidence to support that assumption but it dovetails nicely with one of the FLRW solutions to GR that describes an expanding universe. And so we have an expanding universe model which makes no sense in terms of known physics but which a lot of scientists fervently believe in. That fervent belief, in turn, necessitates subsidiary beliefs in other empirically baseless entities, dark matter, dark energy, the inflaton field and expanding spacetime, not to mention the absurd Big Bang event with its laughably inexplicable original condition.

The expanding universe of the standard model is just as much a delusion as dark matter and dark energy. Until the expanding universe paradigm is relegated to the dustbin of history, modern cosmology will remain an absurdist mathematical fiction with no scientific basis.

Xinhang Shen 13 July 2022

The reason that celestial objects moving nearly frictionlessly is that the viscosity of dark matter (i.e. the medium of electromagnetic waves - aether) is very very small. Of course, Einstein's relativity is wrong and must be abandoned because the relativistic time defined by Lorentz Transformation is not the physical time (i.e. clock time) we use to measure the speed of light. We can see the difference between the relativistic time and clock time in Lorentz Transformation:

There are two relativistic inertial reference frames: (x, y, z, t) and (x', y', z', t'), and (x', y', z', t') is moving at a constant speed v along x-axis of (x, y, z, t), and (x, y, z, t) and (x', y', z', t') are related by Lorentz Transformation. We use the angles of two rotating plates to represent the physical times of the two reference frames. The two constantly rotating plates perpendicular to the x-axis and fixed at the origin of (x, y, z, t) and the origin of (x', y', z', t') respectively are set to have the same rotating angle alpha at any time of t observed from (x, y, z, t), that is, two events (x1=0, y1=0, z1=0, t1=t, T1=alpha) and (x2=vt, y2=0, z2=0, t2=t, T2=alpha) are set to be simultaneous measured by both relativistic time t and physical time T. When these two events are observed from (x', y', z', t'), according to Lorentz Transformation, they become (x1'=-γvt, y1'=0, z1'=0, t1'=γt, T1'=alpha) and (x2'=0, y2'=0, z2'=0, t2'=γ(t2-vx2/c^2)=γ(t-v(vt)/c^2)=γt/γ^2=t/γ, T2'=alpha). These two events are no longer simultaneous measured by relativistic times: t1'=γt is different from t2'=t/γ, but the physical times of the clocks are still the same: T1'=T2'=alpha because the vertical rotation of the plates are not influenced by the horizontal speed. Therefore, relativistic time t is not the physical time T represented by physical clocks, but a meaningless artificial time and thus special relativity is wrong. Moreover, T1=T2=T1'=T2'=alpha tells us that the physical time is absolute i.e. independent of the reference frame, that's why the atomic clocks on the GPS satellites can be synchronized relatively to all reference frames.

Steve Maricic 13 July 2022

I passed physics in high school 50 years ago, so everyone should pay attention to my latest theory of gravity.
Gravity is communicated by waves. These waves can be added or subtracted -- just like sound, sea, and electromagnetic waves. Inside a galaxy, waves from all the stars and planets and other masses tend to add to each other -- increasing the frequency of the gravitational waves.
The higher the frequency, the stronger the pull of gravity. No need for dark matter.
Between two distant galaxies, the gravitational waves tend to subtract from each other. There's a red shift in the frequency, just as with light. The lower the frequency, the weaker the pull of gravity. No need for dark energy.
I can prove my theory to my satsfaction if someone gives me a two million dollar grant. I can prove half of it for one million.

Kenneth Hughes 13 July 2022

How about 5% normal matter and 95% dark energy, (which is the energy of the vacuum due to the passing of time)

Roy Lofquist 13 July 2022

There are two models, Plasma Cosmology and Electric Cosmology, that account for the phenomenon of the anomalous rotation of galaxies. They both model galaxies as homopolar motor/generators. (Search for "Homopolar Galaxy")

Modern observations have revealed vast electrical currents and their magnetice fields both within galaxies and linking galaxies. Electromagnetism is 39 orders of magnitude stronger than gravity. Gravitation force decreases as the square of distance where as magnetic field intensity decrases linearly.

These models don't involve modifications of Newtonian Dynamics.