# Another Dark Matter Theory



## Joshua Jones (Feb 1, 2019)

From my lay level reading, this seems like an interesting theory to describe what I call the Problem of Phantom Gravity (also called Dark Matter, but I don't like how that seems to attribute causal attributes to a gap in our knowledge). Of course, it is also an argument from ignorance, but this relates to an ignorance regarding a force's behavior in circumstances outside our immediate context, rather than ignorance of a form of matter which effectively cannot be detected... 

Any thoughts from those better educated on this field? Is this total hogwash or is this actually viable?

Dark matter may not actually exist – and our alternative theory can be put to the test


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## Brian G Turner (Feb 1, 2019)

There was another article this week about the inability to find WIMPs.

Personally I still think the incidence of gas, dust, and particle radiation has been hugely underestimated. That could certainly explain why "dark matter" supposedly passes through galactic centres during collisions, because all that's being observed is the Center Of Mass rather than an object with mass.

EDIT: Here's the latest failure to find "dark matter": New detector fails to confirm would-be evidence of dark matter


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## Venusian Broon (Feb 1, 2019)

Regarding the OP, interesting, but my intuition is that it suffers from 'give me enough points and I'll curve fit an elephant'.

Conveniently it seems to not impact anything on 'reasonable scales that we might actually mess with and test and when it is invoked for the strange large scale data - is it mathematically flexible so that all data will describe a solution? I.e. is it therefore merely a mathematical artefact of the data?

I fully admit I know little about it, so my question would be: is it, like inflation, something invoked to explain the problem like a mathematical trick, or does it have something fundamental to say about the nature of the universe - which may be tested by other experiments?

Regarding dust and gas - no I doubt it. If dark matter where just big fogs of said stuff around galaxies, they would be instantly detectable - dimming the light of the stars of the galaxy and showing up clearly in light spectra.

What ever dark matter is, or how it will be explained - whether a new force or whatever - it is tied to the fact that it only weakly interacts with normal matter via gravitation.

At least that's my post gym Friday thoughts on the subject. Possibly may change by Monday.


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## Joshua Jones (Feb 1, 2019)

Venusian Broon said:


> Regarding the OP, interesting, but my intuition is that it suffers from 'give me enough points and I'll curve fit an elephant'.
> 
> Conveniently it seems to not impact anything on 'reasonable scales that we might actually mess with and test and when it is invoked for the strange large scale data - is it mathematically flexible so that all data will describe a solution? I.e. is it therefore merely a mathematical artefact of the data?
> 
> I fully admit I know little about it, so my question would be: is it, like inflation, something invoked to explain the problem like a mathematical trick, or does it have something fundamental to say about the nature of the universe - which may be tested by other experiments?


Yeah, I thought it did seems a bit convenient as well, which happens to be my critique of particle explanations of the phenomenon in question as well. I know I'm biased, but it just seems to me more likely that we are missing something regarding gravitational theory than there is a basically undetectable particle which makes up the overwhelming majority of galactic gravity. But that is assuming one thing accounts for all of what we see. It seems more likely that our scientific knowledge is this puzzle...




...and the likelihood of one piece being found to solve the entire thing is a bit low...


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## RJM Corbet (Feb 1, 2019)

I like the idea that we need to bracket things to analyse them.

An example is music. In western music 'middle c' is bracketed and from there a scale of seven whole and six half notes moves outward in a pattern which is unique and forms the basis of our concepts about what music is.

But of course other people have their own brackets and scales and musical forms: Indian music, aboriginal music, etc.

So it's the original 'bracketing' that dictates the analysis. Dark matter and inflation are results of this bracketing. But it may be possible to move the brackets and that will change the whole way of analysing the universe.

String theory does this, but of course the LHC energy hasn't been enough to give evidence of super-symmetry?

Dark Matter may be more about our standard model perception of the universe, than about what the universe really is. 

Any thoughts on this Roger Penrose stuff, posted in an earlier thread in this forum?

Roger Penrose: Dark Matter


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## Venusian Broon (Feb 1, 2019)

Joshua Jones said:


> Yeah, I thought it did seems a bit convenient as well, which happens to be my critique of particle explanations of the phenomenon in question as well. I know I'm biased, but it just seems to me more likely that we are missing something regarding gravitational theory than there is a basically undetectable particle which makes up the overwhelming majority of galactic gravity. But that is assuming one thing accounts for all of what we see. It seems more likely that our scientific knowledge is this puzzle...
> View attachment 49751
> ...and the likelihood of one piece being found to solve the entire thing is a bit low...



Well we know there's still a big step to go with gravity and that's merging it with the world's most successful theory - Quantum Mechanics (I'm biased )

Although all these differences on the very large scale are really the antithesis of how we might naively expect a theory of quantum gravity to differ from General Relativity! But who knows.

There's still plenty of avenues of inquiry regarding what lies beyond the Standard model of particle physics to poke about with. Get that bigger CERN built!


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## Joshua Jones (Feb 1, 2019)

Venusian Broon said:


> Well we know there's still a big step to go with gravity and that's merging it with the world's most successful theory - Quantum Mechanics (I'm biased )
> 
> Although all these differences on the very large scale are really the antithesis of how we might naively expect a theory of quantum gravity to differ from General Relativity! But who knows.
> 
> There's still plenty of avenues of inquiry regarding what lies beyond the Standard model of particle physics to poke about with. Get that bigger CERN built!


Indeed! I, for one, like a world where there is still science to do, and more powerful things to smash together things (assuming, you know, they don't create a black hole that consumes the entire planet...)


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## Joshua Jones (Feb 1, 2019)

Double post... I love Internet issues...


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## Venusian Broon (Feb 1, 2019)

Hey @RJM Corbet - I recently watched Penrose on Joe Rogan, but as far as I could tell - despite being fascinating - he didn't really explain Dark matter or Energy. Rather his theory on some sort of Eternal Universe.

I haven't had time to go over the lecture you posted, but I've put it into my Library and 'to watch' list, so I'll give it a go soon.


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## RJM Corbet (Feb 1, 2019)

Venusian Broon said:


> despite being fascinating - he didn't really explain Dark matter or Energy. Rather his theory on some sort of Eternal Universe.


That seems to be what he's saying. A recurring universe, no inflation, and dark matter 'eribon' particles a sort of gravity hangover from the previous universe. He's a smart guy and seems to me, as a total amateur, to have his research quite well sorted,  etc.

It will be interesting to know your reaction. It's an hour long you tube thing.


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## Brian G Turner (Feb 1, 2019)

Venusian Broon said:


> Regarding dust and gas - no I doubt it. If dark matter where just big fogs of said stuff around galaxies, they would be instantly detectable - dimming the light of the stars of the galaxy and showing up clearly in light spectra.



I've posted a few articles recently about discoveries of huge clouds of cold gas and dust that have previously evaded detection. That in itself isn't enough to cover the "missing mass", but I take it as a strong clue that we've not been looking hard enough, and hugely underestimating the amount of ordinary matter already out there. Anyway, we had a thread on that before here: Half the universe’s missing matter found


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## RJM Corbet (Feb 1, 2019)

Brian G Turner said:


> There was another article this week about the inability to find WIMPs.
> 
> Personally I still think the incidence of gas, dust, and particle radiation has been hugely underestimated. That could certainly explain why "dark matter" supposedly passes through galactic centres during collisions, because all that's being observed is the Center Of Mass rather than an object with mass.
> 
> EDIT: Here's the latest failure to find "dark matter": New detector fails to confirm would-be evidence of dark matter


They're looking for axions now;
Super-Sensitive Device Seeks Axions, Proposed Dark Matter Particles


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## Venusian Broon (Feb 1, 2019)

Brian G Turner said:


> I've posted a few articles recently about discoveries of huge clouds of cold gas and dust that have previously evaded detection. That in itself isn't enough to cover the "missing mass", but I take it as a strong clue that we've not been looking hard enough, and hugely underestimating the amount of ordinary matter already out there. Anyway, we had a thread on that before here: Half the universe’s missing matter found



Yes, but this normal 'extra' matter is nowhere near galaxies. 

Galaxies are fundamentally very bright in the sky, hence my reply. And the problem with galaxies is that many of them clearly show that they are much heavier than we can account for, because of the anomalies in the rotation speeds...hence there can not be this 'dust and gas', or normal matter anywhere near them. Because WE WOULD SEE IT!  Hence gas and dust is not the answer. 

Yes there can be some gas and dust in the cold and dark in-between, in the filaments of the grand universal structure, but that does not actually explain anything at all about the dark matter mystery.


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## RJM Corbet (Feb 2, 2019)

RJM Corbet said:


> dark matter 'eribon' particles a sort of gravity hangover from the previous universe.


Sorry. I got it wrong. The dark matter decays. It's the dark energy continues ...


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## Venusian Broon (Feb 2, 2019)

RJM Corbet said:


> Sorry. I got it wrong. The dark matter decays. It's the dark energy continues ...



My god, the introductions went on a bit....

Yes he does discuss his version of dark matter - Erebons - at the end. Really massive 'classical' particles. 

Of course again, with respect to the theory above, these particles are framed by the constraints of his theory. For there to be eternal big bangs and expanding universes he needs all mass to disappear. Hence these Erebons have a half-life. 

The idea that mass, any mass, has a half-life and will eventually fade away, is actually something that has been speculated a lot. For example, many other theories _need _the proton to decay. 

Some of these decay pathways don't work for Penrose's model, because we still could have Baryonic conservation - i.e. you're just shifting a proton to a positron and a burst of photons. So the positron still happily exists and has a mass. 

But the counter argument could be - well, why do we exist in an universe that consists of Baryons, when it seems more plausible that at the big bang there should have been equal numbers of Baryons and anti-Baryons? They should have all annihilated each other. To explain this there must have been a subtle asymmetry that did not conserve Baryon number. Hence perhaps these extremely long-term decay events don't preserve Baryon number either and, as at the start where the net Baryon number at the big bang was Zero, it will slowly fall to Zero in the very (very) far future. 

Anyway just some thoughts. Yes an interesting idea, that I was also heartened to see might have a possibility of being tested. Which is always a good thing


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## RJM Corbet (Feb 2, 2019)

Venusian Broon said:


> ... that I was also heartened to see might have a possibility of being tested.



In his own words he's hoping LIGO don't ditch the contents of their wastebasket?

Thanks for watching and giving your opinion, VB. 




Venusian Broon said:


> My god, the introductions went on a bit....


Yes, cut straight to 06.31, lol


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## Brian G Turner (Feb 2, 2019)

Venusian Broon said:


> hence there can not be this 'dust and gas', or normal matter anywhere near them. Because WE WOULD SEE IT!



I'll freely admit I don't have empirical data to support my assertion, so here's hoping we'll continue to see further discoveries of ordinary matter with significant masses that have been overlooked.


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## RJM Corbet (Feb 2, 2019)

To me it's like a bucket of water on the end of a rope, being swung in a circle so the water doesn't fall out. You've got 10 feet of rope, but the bucket's still out there 100 feet away still going in a circle with only 10 feet of rope. Where's the other 90 feet of rope to hold the bucket from flying off away?

Ok. More MACHOS (Massive Halo Objects). Perhaps

Different parts of the universe seem to have different gravitational character -- there are galaxies without dark matter;  such fundamental differences may be true of other stuff as well?


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## RJM Corbet (Feb 2, 2019)

repeat


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## RJM Corbet (Feb 3, 2019)

Massive compact halo object - Wikipedia

MACHOs may sometimes be considered to include black holes. 

... Cosmologists doubt they make up a majority of dark matter because the black holes are at isolated points of the galaxy. The largest contributor to the missing mass must be spread throughout the galaxy to balance the gravity. 

A minority of physicists ... believe that the widely accepted model of the black hole is wrong and needs to be replaced by a new model, the dark-energy star; in the general case for the suggested new model, the cosmological distribution of dark energy would be slightly lumpy and dark-energy stars of primordial type might be a possible candidate for MACHOs.

... Neutron stars, unlike black holes, are not heavy enough to collapse completely, and instead form a material rather like that of an atomic nucleus (sometimes informally called neutronium). After sufficient time these stars could radiate away enough energy to become cold enough that they would be too faint to see. Likewise, old white dwarfs may also become cold and dead, eventually becoming black dwarfs, although the universe is not thought to be old enough for any stars to have reached this stage.

Dark Matter Isn't Made From Black Holes - Universe Today

These results suggest that none of the Universe’s dark matter consists of heavy black holes, or any similarly massive objects like MACHOs.  “We are back to the standard discussions,” said Seljak. “What is dark matter? Indeed, we are running out of good options. This is a challenge for future generations.”


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## Daysman (Feb 3, 2019)

I always equate dark matter & dark energy with phlogiston & aether... but that's just me 

By the way, I couldn't get to the paper from the article so I found it here (pdf download top right}:

Long Range Effects in Gravity Theories with Vainshtein Screening


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## RJM Corbet (Feb 3, 2019)

Daysman said:


> I couldn't get to the paper from the article so I found it here (pdf download top right}:



Long Range Effects in Gravity Theories with Vainshtein Screening

Phew! Do you understand that?


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## Daysman (Feb 3, 2019)

The math? No, my math was never strong enough... I can do special relativity but general remains a black box to me...

That said, when I find time, I'll always struggle through _original papers_, if only to gauge the intentions of the authors --  it's a habit from when I was a kid in a public library... also cuts through typically horrible popular science articles...

Edit: sorry, a bit off topic


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## Venusian Broon (Feb 3, 2019)

This is the theory that Joshua Jones highlighted in the OP. Essentially this theory, from my understanding, eventually says that at large distances from very large clumps of matter the effects of gravity of these masses will be altered from what we would normally expect from General Relativity/Newtonian Mechanics. And these alterations and their effects on normal matter are what we're seeing when we see 'Dark Matter'.

Regarding MACHO's in your other post RJM, Penrose skated around it a bit with little explanation, but I think the problem with really heavy individual particles is that because they are very heavy and in a tiny volume, at certain masses then they really are just very small black holes. You have to invoke some principle, or just a hand-wavy 'let's just say they aren't' idea , that they do not collapse into black holes.


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## RJM Corbet (Feb 3, 2019)

Venusian Broon said:


> Regarding MACHO's in your other post RJM, Penrose skated around it a bit with little explanation, but I think the problem with really heavy individual particles is that because they are very heavy and in a tiny volume, at certain masses then they really are just very small black holes. You have to invoke some principle, or just a hand-wavy 'let's just say they aren't' idea , that they do not collapse into black holes.



Ok. Thanks.
Sure I posted it to indicate that neither MACHOS nor black holes are suitable sources for dark matter.

I apologise for labouring the point that the cosmological science from which the DM problem originates, seems to determine that the total amount of baryonic matter won't ever substiantially exceed around 4% of the universe. This is based on big bang calculations, or something?

Even if all the hidden baryonic matter is discovered, it will never bring the total much above 4%. And there seems to be quite a lot of it hidden.

Penrose's 'erebons' would be heavy bosons. They would not add to the baryonic mass of the universe.

His hypothesis does away with the need for inflation -- which no-one seems to like.

Beyond that I'm confused. He seems to be compressing the expansion of the universe, at the 'top' end? Would that do away with the 'lambda' dark energy?


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## Venusian Broon (Feb 3, 2019)

RJM Corbet said:


> Ok. Thanks.
> Sure I posted it to indicate that neither MACHOS nor black holes are suitable sources for dark matter.
> 
> I apologise for labouring the point that the cosmological science from which the DM problem originates, seems to determine that the total amount of baryonic matter won't ever substiantially exceed around 4% of the universe. This is based on big bang calculations, or something?
> ...



Sorry, I was imprecise with my language and also got confused. You are correct, Erebons are not MACHOS.

It just spurred a thought from the Penrose thing, where he states, essentially, that he thinks Dark Matter are these Erebons, but the mass density of them is, I believe, so high, they should really effectively _also _be black holes. Bosons can have mass and I don't see why they can't form or be part of black hole entities (Black holes will happily absorb photons for example). But he hand-waves the issues away saying, 'they are particles, and I want them to remain as particles, so there's probably a Quantum mechanical reason they don't collapse into miniature black holes'. 

Regarding your question about mass in the universe. I believe you can calculate it from measuring the curvature of space (it's almost zero and you can get this info from the Cosmic Microwave Background Radiation data), Now General Relativity says that mass curves space. And therefore there is a certain amount of mass implied by the observation, which can be calculated.

You can then estimate the average mass & energy-mass equivalent density of all the particles we can see (it works out at about one proton for every four cubic metres of space) - apparently 4.9% of the total implied above. (At least that's what Wikipedia thinks.)

And observations of the accelerating expansion of the universe, the Dark Energy, will give you an average energy-mass equivalent density. Which actually turns out to be much smaller than the average density of normal/dark matter within and around galaxies...but this is applied to _all_ space, whereas these high densities of normal and dark matter are confined to galaxies, so when it is all added up by using estimates of the total size of the universe, it is the dominant component with about ~68% of the Universe.

Hence, I guess, the remaining ~27% is Dark Matter, purely by fixing the other two!

Regarding trying to see if there's more normal matter and if it will go above 4.9%.

Yes, you're probably correct. There is matter in the dark voids between galaxies, and this can be estimated by observations of distant galaxies and quasars - via observing absorption lines in their spectra. Perhaps a little paradoxically, given the voids are so dark and empty looking, I've read that only 10% of the ordinary matter of the universe is actually in galaxies. The rest has a very lonely and boring existence in this (mostly!) dark inter-galactic space*. But, by god, there is such a lot of this inter-galactic space compared to the rest! So it adds up.

Finally regarding Penrose's model. From my listening, I believe he is saying that this expansion, or Lambda term, is eternal.

With this 'compression of the top end' he describes this as a mathematical trick. He's not saying the universe actually compresses...but that it's properties are such, when all mass disappears, that one can describe it using some 'hyperbolic' transformation. He points out that this similar property can be used to describe the situation at the very start of the big bang.

So my reading of that was - when all mass disappears and there's just some photons in this empty vast universe, scale and time 'become irrelevant' and the end of the old Eon becomes the seed for the next Eon and it's big bang because all of the conditions and hyperbolic properties are then correct.

I've probably got a lot wrong up there, but I'll leave it there for the mo' 

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* Okay, filaments and halos around and between galaxies seem to be a lot more fun and have much more gas and dust, but there's a small volume of the total size of the universe!


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## RJM Corbet (Feb 4, 2019)

Venusian Broon said:


> Sorry, I was imprecise with my language and also got confused. You are correct, Erebons are not MACHOS.
> 
> It just spurred a thought from the Penrose thing, where he states, essentially, that he thinks Dark Matter are these Erebons, but the mass density of them is, I believe, so high, they should really effectively _also _be black holes. Bosons can have mass and I don't see why they can't form or be part of black hole entities (Black holes will happily absorb photons for example). But he hand-waves the issues away saying, 'they are particles, and I want them to remain as particles, so there's probably a Quantum mechanical reason they don't collapse into miniature black holes'.
> 
> ...


That's extensive. Thank you


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## Parson (Feb 4, 2019)

My interest so exceeds my abilities in physics that I might be considered "dark matter."


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## RJM Corbet (Feb 4, 2019)

Parson said:


> My interest so exceeds my abilities in physics that I might be considered "dark matter."


I sort of like the idea of a recurrent universe, born and reborn from the eventual evaporation of black holes. It somehow rings fair. Although I quite understand that quantum stuff is mostly not fair

Brahma breathes out and the universe comes into being. Brahma breathes in, and the universe is reabsorbed. Again and again eternally.

The wonderful 21st century science available free at home from you tube talks by eminent scientists for laymen is fun to follow -- no maths -- and learning something is one payback of existence at any age that no-one can take away, imo.

Then we can still come here and request clarification of details from resident quantum science dudes, in between work and gym, lol


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