No, ``totally dark matter" is impossible, since any form of matter has an energy-momentum tensor, with certain specific properties, known as energy conditions.

The existence of dark matter doesn’t have anything to do with the existence, or not, of other ``Universes"-but the term ``other Universes" doesn’t make any sense, absent any way of defining Universes other than ours.

The Multiverse is something else. Classical objects are in one state, quantum objects can be in a superposition of states. The superposition of states thecUniverse could be found in is called the Multiverse. The problem id that it’s not known how to define such superpositions. The only measurements that have been possible, to date, only refer to the Universe as a classical object. Attempts to probe the time before inflation, when quantum effects would be relevant aren’t yet feasible.

Thank you very much for your thoughtful answer. I’m sorry for the delay of several days in my reply. Because any freely moving particle follows a geodesic in spacetime, it indeed seems that all matter (which of course includes all energy) must feel gravity G, and hence that totally dark matter is impossible. But: Could there be a coexistent spacetime with its own gravity G´ and hence its own geodesics? Could matter that is totally dark with respect to our (G, E, S, W) Universe exist in the (G´, E´, S´, W´) Universe? Of course, our matter would then be totally dark with respect to the (G´, E´, S´, W´) Universe. The aspect of the Multiverse that you mentioned seems to be the Level III Multiverse, or at least closely related to the Level III Multiverse, discussed by Max Tegmark in his book “Our Mathematical Universe”. Note that if (G´, E´, S´, W´), (G´´, E´´, S´´, W´´), etc., Universes exist, they, like Universes in the Level III Multiverse, could be coexistent with our own (G, E, S, W) Universe (not spatially separated from it by distance). Thus they would be totally dark with respect to our Universe, and our Universe would be totally dark with respect to them.

Matter exists absolutely independently. It does not exist as the result of theoretical considerations, mathematical derivations and descriptions.

Dark matter was never observed. Its existence as the result of theoretical conclusions and their mathematical derivations. One should keep therefore a critical distance to this human mind creation which reflect a certain, rudimentary level of the cognition.

Jack Denur, Stam Nicolis, Hans-G. Hildebrandt

Dear Sirs,

We create our own problems. This is especially clear with dark matter. Dark matter is an effect, not a physical object. This is the effect of increasing the speed of stars on the periphery of galaxies. How to understand it?

We live in an electromagnetic field that fills all space. This is the field of Faraday and Maxwell. The smallest streams of this medium - gravitons - constantly randomly move at the speed of light. The electric and magnetic fields are the directed translational and vortex flows of this medium. We confirm the presence of the field environment every time we bring a smartphone to our ear.

In space, the medium exists in the form of vortices. They are primary in relation to galaxies. In the center of any vortex, the pressure of the medium is less than at the edges. Vortex funnels are sinks for matter. Galaxies are formed in the vortices of the field medium.

The gravitational force of gravity is the pressure gradient of the field medium. The Earth does not attract on the Moon. The pressure of the interplanetary medium pushes the Moon towards the Earth. The stars in the Galaxy are affected by the pressure gradient of the medium inside the galactic vortex. This gradient is more along the edges of the funnel. It creates additional centripetal force.

Thus, the medium of the electromagnetic field can be called "Dark matter". But you don't have to look for it anywhere.

More details are in my profile.

Yours

Valeriy Pakulin

“…. Dark matter interacts with ordinary matter (and ordinary energy) via gravity (G), but not via electromagnetism (E), the strong nuclear force (S), or the weak nuclear force (W). But is totally dark matter that does not interact with ordinary matter (and ordinary energy) at all, not even via gravity (G), possible or impossible?....”

- to answer to this question it is necessary before to understand – what is “matter”? what is “fundamental Nature force”? – and fur her more concretely what are “G”, “E”, “S”, and “W”, Forces?

- including really in the mainstream physics the Force “G” doesn’t exist, since the well observed gravitational objects/systems/interactions/processes in the mainstream are claimed as actualizations of interactions in systems ““mass-spacetime-mass”, for what, though, so it is necessary before to understand what are space/time/spacetime?,

- and, relating to

“….. If totally dark matter is possible, could there be other Universes with their own sets of forces (G´, E´, S´, W´), (G´´, E´´, S´´, W´´), etc., coexistent with our own (G, E, S, W) Universe, with each such Universe (including our own) interacting within itself but not with the other Universes? Is this a possible or impossible aspect of the Multiverse?..”

- what is “Universe”? – including so further what is “Multiverse”?

Really all the questioned terms/fundamental phenomena/notions in the questions above in the mainstream are fundamentally transcendent/uncertain/irrational ones, and the questions in the mainstream can be answered only as some transcendent, in better cases phenomenologically correct, claims that to certain extent are fitted with experimental data.

Correspondingly, say, that in framework of the mainstream

“…Because any freely moving particle follows a geodesic in spacetime, it indeed seems that all matter (which of course includes all energy) must feel gravity G, and hence that totally dark matter is impossible. ….”

- is [besides that the words “freely moving” isn’t applicable in this case, particles move freely inertialy in the flat Euclidian space; if it moves in a Gravity field, it isn’t free] really - in very certain sense - correct, however in this case again quite natural question appears – why and how the “curved spacetime” forces particles, bodies, etc., to move following concrete “geodesics” in spacetime?; what is postulated in the GR really completely ad hoc, and so the theory doesn’t contain any answers on the last question, or at least some rational physical grounds for such postulate.

Really, as that rigorously shown in the Shevchenko-Tokarevsky’s “The Information as Absolute” conception

https://www.researchgate.net/publication/260930711_the_Information_as_Absolute, and

the informational physical model, which is based on the conception, https://www.researchgate.net/publication/354418793_The_Informational_Conception_and_the_Base_of_Physics

- Matter’s spacetime fundamentally isn’t, of course, the rather strangely postulated in the ST/GR as the real ones, strange imaginary [mathematically] Minkowski and pseudo Riemannian spaces. That is the fundamentally absolute, fundamentally flat, and fundamentally real [mathematically]“Cartesian”, [5]4D spacetime with metrics (cτ,X,Y,Z,ct), which is fundamentally nothing else than the [5]4D “empty container”, where Matter – and everything in Matter – is placed, exist, and constantly changes its state. The emptiness fundamentally cannot be impacted by anything in Matter, and fundamentally cannot impact on anything in Matter, and so in the emptiness fundamentally any “geodesics” cannot exist.

However concrete spacetime of every concrete [fundamentally only informational] patterns/systems concretely is determined just by its content – by independent degreases of freedom of changes on fundamental level of the contained elements, in the informational system “Matter”, which is based on a rather simple binary reversible logics, that are the binary reversible fundamental logical elements [FLE], which have the main 4 degreases of freedom at the state changing – “FLE binary flips” – and so Matter’s spacetime is as it is above.

Besides, as that looks rather rationally from existent experimental data, FLEs have additional logical marks, which relate to the four fundamental Forces above, including Gravity Force, and indeed, as that again follows from experiments, really practically everything in Matter, at least every particle, has the Gravity charge – “gravitational mass”, and so in Matter everything gravitationally attracts everything,

- but that fundamentally isn’t caused by some “spacetime curvature”. That is determined by the Matter’s concrete design – and that only specific particles have rather specifically in Matter the charges of the 3 other Forces is also determined by the design, more see, including about what is “dark matter”, section “Cosmology” in https://www.researchgate.net/publication/358801098_Title_page_Article_type_Review_Title_The_informational_physical_model_some_selected_fundamental_problems_in_physics

In the conception above it is rigorously proven that there exist absolutely for sure nothing besides some informational patterns/systems of the patterns that are elements of the absolutely fundamental and absolutely infinite “Information” Set, including Matter is some the Set’s element.

Correspondingly in the Set can, in principle, exist any number of Matter’s versions, if are based on the same FLE design, which are on infinite distances, and so don’t mutually interact, in the one [5]4D spacetime above. As well as in the Set can, in principle, exist any other “Matters”, FLEs of which differ from the Matter’s ones, with other fundamental Forces, etc.; however all real “Matters” can exist stably in the Set in long time only if every of which is logically closed logical structure, which so don’t interact with other the Set’s elements.

Etc. – [again – in principle] in the Set there can exist a lot of some “verses” and “Multiverses”, however that has really only too “academic” interest, and has by no means some sense in real physics, which studies the concrete Matter; note only here that such

“…The Multiverse is something else. Classical objects are in one state, quantum objects can be in a superposition of states. The superposition of states the Universe could be found in is called the Multiverse. …..”

- really don’t exist, practically everything in Matter is/are just some “classical objects”, and all “superposition of states” really are quite negligible on the macro and cosmological scales – and in most of cases on the QM scale, and introducing in physics the term “Multiverse” is really senseless fantasy. In mainstream there exist a lot of other fantasies, though.

More about what is, with well non-zero probability, Gravity Force – see section 2.9 “Mediation of the forces in the 2-nd link above.

Cheers

Jack Denur ,"Dark matter interacts with ordinary matter (and ordinary energy) via gravity (G), but not via electromagnetism (E),...."

It is widely acknowledged, and we are increasingly finding that the universe is composed of huge filamentous structures of ionized plasma with galaxies, with separate cold invisible regions of positive and negative ions that interact between electrodynamically over long distances. It follows that not gravity (G), but electromagnetism (E) is the decisive force in space.

Thank all of you for your very thoughtful answers, even though I may not agree with every point.

The fiction of so-called "dark matter" is very simply the outcome of fictitious theories of gravity of Newton and Einstein! The following publications give mathematical, scientific and philosophical reasoning as to why and how this fiction came about!

Article KEPLER -NEWTON -LEIBNIZ -HEGEL Portentous and Conflicting Le...

Article The Mystery of the Lorentz Transform: A Reconstruction and I...

Article Quō Vādis Theoretical Physics and Cosmology? From Newton's M...

Thank you for your post, Abdul Malek, even though physics is independent of political and economic opinions.

Jack Denur It seems that you made your comment on my post prematurely and with preconceived judgment, before going through any of the references cited. This is very unfortunate for the health of natural science!

Dear all, I realize it very well that what I am saying in my first comment above is stunning and unbelievable! I am questioning long established and much venerated theories of physics, talked, taught and written about and been subjects of text book for hundreds of years!

But my question is: Does my questioning have any validity? If so, isn’t science about revealing objective truth?

Hi Abdul Malek, What I meant was that the laws of physics would still be the same even if no one ever thought of dialectical materialism or of any other political or economic philosophy. Indeed, they would still be the same if life on Earth, or Earth itself, never existed. We might INTERPRET or even CONSTRUE the laws of physics in the light of our political or economic philosophy, but the laws of physics THEMSELVES are independent of our philosophies.

“…We might INTERPRET or even CONSTRUE the laws of physics in the light of our political or economic philosophy, but the laws of physics THEMSELVES are independent of our philosophies.….”

- that looks as quite typical mainstream philosophy and sciences claim, i.e. since in the mainstream everything on fundamental level is fundamentally transcendent/uncertain/irrational, any transcendent and evidently irrational claims are quite natural and completely legitimate;

- including yeah, in the mainstream some things without any problem are interpreted or even construeed in in the light of other fundamentally independent things …

The last post that is really clarifies the thread question is the SS post on page 1.

Cheers