Dark Matter

[BMAONE23]

Thanks for the ArXiv and ADS links. This is some interesting info to read through and digest.

[rodly]

Thank you Nereid for pointing out my error.

Nereid said:

First, the Shaposhnikov and Lev Titarchuk preprint includes the following:
Quote:
For the mass of the BH in Cyg X-1 we have:

MCygX-1 = [...] (8.7 +/-0.8)Msol

[...] This inferred value of Cyg X-1 BH mass is slightly lower than 10 Msol given by Herrero et al. (1995) (with no error bars quoted) and it is within the mass range found by Gies & Bolton (1986).

Second, the estimate for the Cyg X-1 BH depends upon the estimated mass of a different BH in another x-ray binary (GRO J1655).
Quote:
how many other measurements of the distant items in the universe have similar errors, and are all calculations assuming the same degree of accuracy. The above article does not state how much the figure they got differs from accepted figures but:
http://www.astro.uiuc.edu/~kaler/sow/cygx1.html
does state that Cygnus X-1 has a mass of 40 stellars plus or minus 10.

Actually, if you read that page a little more carefully, you'll see that this estimate refers to the bright O supergiant in the Cyg X-1 binary, not the (invisible) BH.

I admit I used the wrong mass, the mass I should have used:

Estimates from the effect of the compact companion on the supergiant lead to a black-hole mass of 20 (give or take 5) times that of the Sun,

The 500% should have read 300%.

I hope I do not come across as being confrontational to anyone, but my point is not so much the size of the margin of error, but that the margin of error exists.

Perhaps the keyword in the last quote is "Estimates" for Nereid used it in his post as well.

This is likely where a lot of doubt is created, for estimates built upon estimates lead to larger and larger margins of error. And I know, there is at present no other way for any measurement has a some margin of error.

While I choose an example that may not have met someone's criteria for scientific standard, it was, is, and will be the standard by which most people receive their information, i.e. some portal to science information such as APOD,New Scientist. Not all people want to discuss the subject at the astronomer's level, and not many laymen can(myself included in the latter).

Yet science is about gaining a better understanding. If we were to suddenly start floating we'd realize that someone turned off the gravity generator and we wouldn't have to be scientists of any description to make that realization. To the astronomer something is amiss, so Dark Matter has been invented, and by doing so put the rest of us afloat.

My own personal unscientific(not tested) theory is that the 'something amiss' is a combination of our not full understanding of gravity, and/or mathematics but I do not claim that it is any better than Dark Matter, but I certainly feel more comfortable with it.

[Nereid]

Thank you Nereid for pointing out my error.

Nereid said:

First, the Shaposhnikov and Lev Titarchuk preprint includes the following:
Quote:
For the mass of the BH in Cyg X-1 we have:

MCygX-1 = [...] (8.7 +/-0.8)Msol

[...] This inferred value of Cyg X-1 BH mass is slightly lower than 10 Msol given by Herrero et al. (1995) (with no error bars quoted) and it is within the mass range found by Gies & Bolton (1986).

Second, the estimate for the Cyg X-1 BH depends upon the estimated mass of a different BH in another x-ray binary (GRO J1655).
Quote:
how many other measurements of the distant items in the universe have similar errors, and are all calculations assuming the same degree of accuracy. The above article does not state how much the figure they got differs from accepted figures but:
http://www.astro.uiuc.edu/~kaler/sow/cygx1.html
does state that Cygnus X-1 has a mass of 40 stellars plus or minus 10.

Actually, if you read that page a little more carefully, you'll see that this estimate refers to the bright O supergiant in the Cyg X-1 binary, not the (invisible) BH.

I admit I used the wrong mass, the mass I should have used:

Estimates from the effect of the compact companion on the supergiant lead to a black-hole mass of 20 (give or take 5) times that of the Sun,

The 500% should have read 300%.

I hope I do not come across as being confrontational to anyone, but my point is not so much the size of the margin of error, but that the margin of error exists.

Perhaps the keyword in the last quote is "Estimates" for Nereid used it in his post as well.

This is likely where a lot of doubt is created, for estimates built upon estimates lead to larger and larger margins of error. And I know, there is at present no other way for any measurement has a some margin of error.

Welcome to the world of astronomy!

Understanding the (possible) sources of uncertainty ("error") in astronomical observations and models, and as accurately as possible estimating them, is a critical part of almost all the scientific work of astronomers (and a great many other scientists too).

If you read (observational) papers in ApJ, AJ, MNRAS, etc, you will see just how much effort goes into this aspect.

While I choose an example that may not have met someone's criteria for scientific standard, it was, is, and will be the standard by which most people receive their information, i.e. some portal to science information such as APOD,New Scientist. Not all people want to discuss the subject at the astronomer's level, and not many laymen can(myself included in the latter).

Indeed.

That's one reason why I like to suggest that questions - no matter how formed or formulated - are a better approach to gaining a deeper understanding than assertions based on press releases (and far better than conclusions in the form of childhood tales or parables).

While I can't speak for others, I feel that bald assertions that can quite easily be shown to contain basic flaws are much more likely to generate a 'robust' (shall we say) response than essentially the same content, presented as questions.

Yet science is about gaining a better understanding. If we were to suddenly start floating we'd realize that someone turned off the gravity generator and we wouldn't have to be scientists of any description to make that realization. To the astronomer something is amiss, so Dark Matter has been invented, and by doing so put the rest of us afloat.

My own personal unscientific(not tested) theory is that the 'something amiss' is a combination of our not full understanding of gravity, and/or mathematics but I do not claim that it is any better than Dark Matter, but I certainly feel more comfortable with it.

Indeed.

Fascination ... discomfort ... thrill ... dismay ... there are all sorts of emotions aroused by 'dark matter'.

The 'sound bite summary' is that there are only two classes of answer (in terms of scientifically valid explanations of the relevant observations, uncertainties, errors and all): 'cold' non-baryonic matter and a fundamental misunderstanding of gravity. In light of the extraordinary success of General Relativity*, and the incompleteness of the best we can do wrt particle physics*, my guess is that most physicists, astronomers, etc would rather place their bets on non-baryonic matter.

However, as we're doing science, the only way to find out is to do more experiments (which is what thousands of particle physicists are doing) and make more observations (which is what thousands of astronomers are doing).

*GR: a fascinating topic; to me the extent to which theory accounts for experiment and observation, across such vast ranges, is truly awesome. The Standard Model (SM): the region of particle energy/rest mass space we've probed so far, with our earthly accelerators, is truly puny compared with what we know, from direct observation, the universe can do ... on a daily basis, apparently, tonnes and tonnes of mind-bogglingly energetic cosmic rays are produced by nature's particle accelerators, yet the SM has only been investigated in a trivially small part of this range.

[Nereid]

We've been over this, and over it, and over it, and over it, and ...

A simple "yes" or "no" would have sufficed.

You can believe whatever you wish ... no one, least of all me, denies you your beliefs.

I just can't discuss them publicly, particularly if they don't jive with your personal position on that topic?

Not in this forum you can't ... or, more specifically, of course you are welcome to state you opinions (within certain limits); however, you are not welcome to use this forum as a means to promote those opinions unless you can show, by references to papers published in relevant, peer-reviewed journals, that they meet the basic requirement of this forum ("this is a scientific forum").

However, as this is a scientific forum, and as it is now very clear that your ideas of what science is, and what modern astronomers actually do, are incongruent, I don't see why you'd even want to keep posting here.

I post here because I would like them to become more congruent of course. Whether your position must give, or mine must give remains to be seen, but something must give for that to occur.

This is, then, most certainly the wrong thread to do that in (we have another much more appropriate); and it is also the wrong forum ... the starting point for this forum is astronomy, as a science, today, per the way modern astronomers actually do their research (publish their findings, etc, etc, etc).

That you are not be happy with the way astronomy, as a science, is done, today, seems clear. However, this Cafe is not the place to continue to try to make your case in this regard. FWIW, there are a number of good, peer-reviewed, journals on the history and philosophy of science, and several internet discussion fora too. Why not write some papers for those journals, or start threads in those fora?

Specifically, wrt this thread on dark matter, you have nothing to offer in terms of an alternative, scientific, explanation of the relevant astronomical observations.

I did suggest you consider some alternatives to non-baryonic matter which you simply rejected out of hand, only because it has not been published.

Are you suggesting that the 'ground rules' for this site be changed?

Should we open the Cafe to speculations about DM being caused by little green men from Mars, or a mass delusion by astronomers, or the work of an ineffible being being mischievous, or ...?

Should we ask you, Michael Mozina, to adjudicate on what 'alternatives to non-baryonic matter' are acceptable to be presented here (and what are not)?

But what does that have to do with your inability (or, if you prefer, continued failure) to present an alternative, scientific explanation of the relevant astronomical observations?

IMO, you are dangerously misrepresenting the scientific method and how it operates. It is entirely possible for someone to falsify one idea without positing a better one to explain the same observation. One can point out the flaws in another individual's theories without having any other alternatives. It is not required for me to explain the observations in question for me to point out that your definition of non-baryonic matter lacks empirical evidence. A distant lensing effect is not evidence of anything other than "unidentified mass". In no way does it provide evidence of 'dark matter' as in non-baryonic matter that passes through walls and such. The "dark matter" proposed, and the properties that the mainstream claims has, are simply untestable. If you had a gram of dark matter for us to experiment with, then they would not be the case. Since you cannot produce a single gram of it, nor any experiment to demonstrate it exists, I have no evidence it could have the lensing effects you suggest, or that it could have any of the properties you claim it to have.

We have been over this, and over it, and over, and ...

For the nature of modern astronomy, as a science, please post in the relevant thread in this Cafe.

For the details of what, in modern astronomy, the relevant hypotheses and theories are (not what you imagine them to be), please ask direct questions (you may be surprised at the answers).

For details of why hypotheses to the effect that 'baryonic matter as DM' are inconsistent - at the many sigma level - with the relevant astronomical observations, please ask (do not assert).

Threatening to ban me for pointing that out is purely an act of killing the messenger Nereid. It won't make the evidence any stronger, nor will banning me solve anything.

I don't believe that I am asking for anything I wouldn't ask of any branch of science. All I am requesting of you is that you provide empirical evidence to support your positions on these specific topics. Is the fact that you can't provide any such support in a controlled scientific test somehow my fault personally?

[snip]

We have been over this before too, and over it, and over, and over, and ...

First, this is a forum about (modern) astronomy, as a science.

You keep saying that like a mantra, as though someone here has denied it. Nobody here has denied that statement Nereid, least of all me personally. How does that statement even address my point? How is it somehow my fault that you can't produce a single gram of dark matter, nor any controlled scientific test to demonstrate it actually exists?

And there, in your very own answer, is the reason.

1) Your own view of the nature of modern astronomy is inconsistent with how modern astronomy, as a science, works; ergo, your statements are, at some level, irrelevant to what this forum is about.

2) Within the framework of modern astronomy, as a science, your so-called alternatives are non-scientific.

But, once again, we've been over this point before (and over, and over, and over, ...).

Second, even within your own, freely expressed, views on astronomy, you concede the impossibility of what you are asking for (take me to an earthly lab where controlled experiments are being done on systems of ~1 billion masses, each of mass ~10^(30+/-2) kg, to use just one example).

I only conceded that not every physical structure that exists in space can be duplicated here on earth, particularly the heavy things. That doesn't mean that I can't created electrical flow here on earth to mimic the Birkeland currents that drive the aurora. Birkeland was able to duplicate the *idea* on earth, if not the actual aurora. Not everything is untestable.

Getting there ... in which lab, on Earth, have the aurorae which Birkeland observed, in his 190x expedition(s), been reproduced?

If, OTOH, you accept that "the *idea*" is all that can, or should, be tested, then non-baryonic dark matter can be said to exist, in rich clusters, and that its mass exceeds that of baryonic matter by a factor of ~5-10.

After all, GR has been tested across far, far more ranges of physical parameters, in far, far more physical environments, to far, far greater degrees of accuracy, (etc) than anything Birkeland ever published.

The one thing I have always appreciated about this forum is that it has followed a freedom of speech policy to the letter. It would be a pity to see it become something less tolerant of skeptical viewpoints only because of it's discomfort over public dissent. In no way would that serve anyones interest over the long haul IMO.

Once more, this is a scientific forum, devoted to astronomy.

Who here has denied that Nereid? How does that address my point? Free speech allows for scientific ideas to be discussed openly. I should be free to criticize your theories just as you are free to criticize mine. Your theories being the "mainstream" position, does not make them immune from criticism. That is what makes science "better than" a religion.

Anyone can, objectively, assess the extent to which your ideas are scientific, in the sense of this forum - references to papers published in relevant, peer-reviewed journals.

If you cannot cite such papers, then, by definition, your so-called criticism is non-scientific (and so beyond the scope of this forum).

The way astronomy, as a science, is done today is pretty easy to describe (the role of theories, the criteria for testing the validity of theories; the primacy of good observations; papers published in the relevant, peer-reviewed literature as the vehicle; etc).

Yes, but I've had some of my idea published over the past two years Nereid. Publishing material does not make the material "right" or "wrong", it only makes it "published".

Indeed.

And what does it have to do with dark matter?

Questions are always welcome; answers are expected to be from within the mainstream of modern astronomy*.

So why do you have a tough time with me asking your side for empirical evidence of dark matter?

Your questions in this regard, as they relate to astronomy, have been answered, many times, in many threads.

That you do not accept what is 'empirical' in modern astronomy is not a short-coming of the answers (it is, so we now know, due to your rejection of key elements of modern astronomy, as a science).

As I hope is clear by now, if you wish to pursue this further, you need to find a forum other than this ...

If you think you have a viable alternative (to some accepted, modern astronomical work), then please make sure you can cite relevant papers published in relevant peer-reviewed journals to back up your ideas ... before you present them.

Again however, it is scientifically unnecessary for me to provide any alternatives simply to critique the mainstream position.

Let's just ask a very simple question:

Do you have empirical evidence that dark matter exists (as opposed to missing mass) and can have some effect on photons or normal matter, yes or no?

Again: which of the sets of good, pertinent astronomical observations of rich clusters have you not read? Which of the analyses, based on the relevant physics, of those observations have you not read?

Finally, which part of my explanation of the role of theory, in modern astronomy as a science, did you not fully understand?

Perhaps an analogy, with contrast turned way up for effect, might help: what is the isospin of the dream which I had 3 nights ago? or: which of the five basic human tastes (salty, sour, bitter, sweet, umami) is the electron?

[Nereid]

Nereid,
Do these aforementioned "Relavent, peer reviewed Journals" publish papers which present views tangent to modern accepted theories WRT BBT, Dark Matter, etc.? Or does the peer review process "weed out" the alternate viewpoint papers?

http://arxiv.org/find/grp_cs,grp_math,g ... /0/all/0/1

Not really. A published, peer reviewed paper is not an automatic guarantee of something being true.

It would seem to me that you might be asking the impossible of Michael and others to reference theory papers that peer review Journals will not publish.

You'll notice that Nereid will have to qualify her publishers list to exclude my materials. It's not only that she requires it to be 'published', it has to b published by the mainstream, which is certainly skewing the conversation toward a mainstream position, as though the peer review process guarantees truth. It is in essence an appeal to authority fallacy.

In your view, to which peer reviewed journals should they turn to find the data needed to qualify as acceptable references?

Good question. Her list of "acceptable" publications will certainly not include any that have published my work.

Perhaps you'd be kind enough to cite the page(s) in these papers which directly address the astronomical observations relevant to dark matter?

[Nereid]

Fleshing out of quantum mechanism, resolution of the dilemmas in classical electromagnetism (i.e. where Maxwell's equations fail, and how to fully address this): ~1920s.

I think it's safe to say however that Birkeland understood the basics about electricity and it's effects on his experiments.

Birkeland knew more about quantum mechanics, a decade or so before the key papers were published, than Heisenberg, Schrödinger, et al.?

I don't think so.

If nothing else, a consistent account of the (well-known) lines in the spectra of aurorae had to wait until the Schrödinger atom ... which was not published until well after Birkeland's death.

Problem solved: Michael Mozina's science seems to have its roots in the classical physics of the 19th century ...

Is that a bad thing somehow? Note here I'm assuming a QM universe as I have explained to you on a number of occasions now. I do however think that GR theory is "more" useful to explain gravity, whereas "gravitons" seem somewhat lacking in empirical evidence. I can't entertain the idea idea that gravitons exist, but like all things, I need some empirical evidence to support theory before I jump on board.

It goes a long way to accounting for your misunderstanding of the role of theory in modern astronomy (for example) ...

It seems that the deep metaphysical questions - and their resolution - which the relativity and quantum mechanics revolutions forced physicists (and astronomers) to confront sailed right over your head ... because you are stuck with a 19th century mindset.

while some gloss from the quantum (and, earlier, relativity) revolution seems to have been absorbed, the basics have not been updated ...

I would say that the mainstream never incorporated the basics. They recognize that electrical current flows between the sun and the earth, but they rarely consider it's effect on distant events. It is as though electrical currents end at the edge of the solar system.

So why do you still post here?

It seems to me you have yet to confront even the simplest of the difficult questions which the relativity and quantum mechanics revolutions forced on science (especially physics); questions which don't need the ambiguities of modern astronomy to resolve - you can go straight to the laboratory!

No wonder communication has been so difficult!

One gets the feeling that that strawman is coming soon.

Of course, the actual process by which Birkeland came to write his papers was almost certainly unlike the above ... the historical development of an idea (before it gets written up as a paper) and the logical structure of a well-developed theory do not necessarily line up.

I don't follow you. Birkeland took *measurements* of the field strengths of the aurora. He built controlled experiments to test his theories about the effect of EM fields on objects in space. He took pictures. He followed the letter of the scientific method. Whatever "leap" he made about the aurora were all based on logical forces of nature that he could play with in his lab and simulate in his lab. He required nothing "dark" to explain aurora activity.

Birkeland didn't propose new forces of nature to explain nature. He proposed a known force of nature to explain nature. You are using metaphysics to explain nature, so of course there is no real comparison between these two approaches.

[snip]

In light of the relevant historical dates, the irony in this part of Michael's post is rich indeed!

At the time Birkeland was working on his terrella and observing aurorae, Thompson's 'plum pudding' atom was shown, by Rutherford, to be wrong. That in turn created a deep crisis: classical electromagnetism required that atoms comprised of electrons orbiting positively charged nuclei decay in a burst of radiation in tiny fractions of a second. A 'new force of nature' was required, one that was not properly worked out until after Birkeland's death.

Birkeland could produce electrons in his lab Nereid. He may not have understood all the details about atoms and electrons, or QM, but he certainly nailed the flying ion and flying electron concept, with our without QM. That my friend is a real "scientist" that is far ahead of his time.

Another classic ... do you not realise, Michael, just how unsatisfactory your so-called explanation is?

Do you not understand that whatever theory of the atom Birkeland used, implictly or explicitly, it must have been seriously flawed?

Have you really missed the fatal blow that your statements about Birkeland deal to your whole view of the nature of astronomy, as a science?

And what is this 'new force of nature' - quantum mechanics - if not 'metaphysical'? And if not 'metaphysical', surely it is quintessentially mathematical?

QM is not "metaphysical", only subatomic. We can do real experiments to test the validity of QM and it's mathematical theories. No "faith" is required.

May I quote you on this?

In another forum - one devoted to physics, testable in earthly labs, would you be prepared to propose, and defend, this?

[kovil]

If, as Michael's ideas run to, the bulk of our sun is an iron mix in a rather static form and occupying over 90% of the diameter of the sun (correct me if I have some things wrong here Michael, I'm dropping in on this conversation from the library in Canada) ; and all stars are basically this kind of construction, then dense clusters of galaxies and even the galaxies themselves, would be containing vastly different mixes of elements than in our presumtions. Dark matter might not be needed. Composition of the earth assumptions, lead to Newtonian calculations for the mass of the sun and its gravity to allow earth's orbit parameters which exist. Could our calculations on earth's mass and the sun's mass be way off? If both contained much more iron would the orbit still be what it is? Is this a way to check the solar composition model?


Our sun being our closest star for observation is invaluable for data.
Fortunately vast amounts of data are presently being collected.

---

I do want to thank you again Neried, on several occasions while writing, I have phrased what was initially stated as a statement, into a question. It is much more powerful to ask a question, than to make a statement !
And gives the writer the aura of greater humility as well.

(still learning to ask questions, tho missing opportunities to do so all over the place)

[Nereid]

Note: I split two of Michael Mozina's posts, and one of kovil's, from another thread in the Cafe, and merged them into this thread, as they are about DM (not the origin of the universe).

The earlier Mozina post is dated 29 May 2007, with timestamp of 8:41; the other two posts immediately preceed this one.

[Nereid]

[snip]

In other words, what is it that you think your are made of harry, if not baryonic matter?

So what are electrons if not non-baryonic matter? What do you have against plasma cosmology as a theory if you're looking for non-baryonic mass?

Good point ... darn those astronomers, always confusing us with misleading shorthand! I mean, to them oxygen is a 'metal'!

If you think you can make a case that the observed DM is comprised, to ~90+% by mass, of electrons, please proceed.

If not ...

[snip]

http://cosmologystatement.org/

As that link demonstrates, there is a growing dissatisfaction with the "dark" side of astronomy today. Inflation is unlike any known vector or scalar field known to exist in nature. No other known vector or scalar field would maintain near constant density over many exponential increases in volume. It's literally a 'supernatural' field of energy, unlike any other field of energy known to exist in nature.

The scientific question is not whether there is disquiet, or discomfort; it is whether there is a scientifically viable alternative to the consensus 'cold dark matter'.

On another topic: this site gets of the order of 20 to 50 spam posts a day. Unless anyone who posts yet another link to this statement can provide a good scientific reason for doing so, beyond the (mostly non-scientific) reasons in the dozens of posts which already link to it, I think the time will soon come to start treating it as spam.

[Nereid]

If, as Michael's ideas run to, the bulk of our sun is an iron mix in a rather static form and occupying over 90% of the diameter of the sun (correct me if I have some things wrong here Michael, I'm dropping in on this conversation from the library in Canada) ; and all stars are basically this kind of construction, then dense clusters of galaxies and even the galaxies themselves, would be containing vastly different mixes of elements than in our presumtions. Dark matter might not be needed.

That is a very good recap of my argument actually.

Composition of the earth assumptions, lead to Newtonian calculations for the mass of the sun and its gravity to allow earth's orbit parameters which exist. Could our calculations on earth's mass and the sun's mass be way off? If both contained much more iron would the orbit still be what it is? Is this a way to check the solar composition model?

There are several "ways" to check the composition, but there is a certain amount of "interpretation" in each of those methods. The most common way to 'measure' a sun's composition is spectrometry, but that method *assumes* that stars are not "mass separated" by atomic weight. In other words, it assumes that the suns elements stay reasonably "mixed" rather than separate as they do here on earth in gravity wells and strong magnetic fields.

The problem with that method is that stars are mass separated by atomic weight and hydrogen and helium being the lightest elements work themselves highest into the solar atmosphere where it's hottest. That causes the outer layers of hydrogen and helium to emit the most photons and that causes astronomers to believe that the sun is mostly hydrogen and helium.

Manuel's methods used lunar soil samples and comet samples to demonstrate that the sun mass separates the elements in it's atmosphere and the abundance of elements more closely resembles that of an ordinary meteorite, not unlike the Earth, Venus and Mercury, it's 3 closest neighbors.

Our sun being our closest star for observation is invaluable for data.
Fortunately vast amounts of data are presently being collected.

Indeed. In fact I'm just now getting my hands on the new Hinode data. All I can say is "wow'. The thing about our technology gains recently is that they will provide us with irrefutable evidence about the field strength of coronal loops and that will allow us to calculate current flow with great precision. The solar satellite images also show a 'layer' of the solar atmosphere that does not rotate differentially compared to the photosphere. You can see it in running difference images from SOHO, TRACE and now STEREO images. There is a "rigidness" to the "structures' seen in these images that is unlike any of the sun's flimsy plasma layers.

You were asked about this before, I think, but didn't answer ... how does the composition of the Sun relate to the three sets of good astronomical observations of the size and distribution of mass in rich clusters (gravitational lensing, the dispersion of radial velocities of cluster galaxies, and the intensity and temperature of x-ray emission)?

Please be sure to answer this question in your next post (or two) in this thread, Michael.

Also, in which published paper, in a relevant, peer-reviewed journal, have you presented this 'heavy suns' account of the observed mass distribution in rich clusters?

[Nereid]

If, as Michael's ideas run to, the bulk of our sun is an iron mix in a rather static form and occupying over 90% of the diameter of the sun (correct me if I have some things wrong here Michael, I'm dropping in on this conversation from the library in Canada) ; and all stars are basically this kind of construction, then dense clusters of galaxies and even the galaxies themselves, would be containing vastly different mixes of elements than in our presumtions.

Michael made the same, basic, mistake earlier ... this assumes that the bulk of the mass of rich clusters is in the form of stars.

You don't need to go to rich clusters to find good observational evidence that is inconsistent with this idea - the ISM and IGM (inter-galactic medium)/ICM (intra-cluster medium) are both more massive than the stars in (cluster) galaxies, and are composed almost entirely of H and He.

However, there are far, far bigger problems with this idea than merely an inability to account for the observed size and distribution of mass in rich clusters ... (not a topic for a thread on DM however).

Dark matter might not be needed. Composition of the earth assumptions, lead to Newtonian calculations for the mass of the sun and its gravity to allow earth's orbit parameters which exist. Could our calculations on earth's mass and the sun's mass be way off?

In a word, no.

Estimates of the mass of the Earth, Sun, stars in binaries, SgrA*, etc, etc, etc are blind to the composition of the bodies ...

Take Newton's universal law of gravitation, for example: the "m1" and "m2" in the basic equation say nothing whatsoever about composition ... it's just "M(Earth)" or "M(Sun)" that you get when you analyse the motions of the planets and moons ...

If both contained much more iron would the orbit still be what it is?

Yes (except if the mass were different, by even 0.1%).

Is this a way to check the solar composition model?

[snip]

Yes ... there are many ways ... but they will not give any results that are inconsistent with estimates of the mass of the Sun, obtained by analysing the motions of the planets (for example).

(and discussion of the rest of your question is OT for this thread).

[Nereid]

[snip]
So what are electrons if not non-baryonic matter? What do you have against plasma cosmology as a theory if you're looking for non-baryonic mass?

Good point ... darn those astronomers, always confusing us with misleading shorthand! I mean, to them oxygen is a 'metal'!

You sidestepped my question with more examples of astronomical sloppiness? Care to try again? How do you know that what you are calling "dark matter" isn't at least partially composed of flowing streams of electrons?

If you think you can make a case that the observed DM is comprised, to ~90+% by mass, of electrons, please proceed.

No, I am suggesting it probably could be comprised of a number of *known* items and have nothing to do with "dark matter" at all.

I'd like a straight answer on one point: Could your non-baryonic dark matter be at least partially composed of electron streams?

No ... at least not unless there's something very radically wrong with our understanding of the electromagnetic force (either the full, quantum version - QED, or the classical version - Maxwell's equations).

Why? Essentially because the electron (a non-baryonic particle) has only ~0.1% of the mass of the lightest, stable baryon (the proton).

A quick, OOM, calculation, using the ~10^39 difference in the scale of the EM force vs gravity, suggests that an electron/proton imbalance sufficient to amount to the mass of the galaxies in a rich cluster (let alone the mass of the IGM) would render galaxies unstable over periods of years ...

The scientific question is not whether there is disquiet, or discomfort; it is whether there is a scientifically viable alternative to the consensus 'cold dark matter'.

I don't know what 'cold dark matter' is. I've never seen any, certainly not the non-baryonic variety.

On another topic: this site gets of the order of 20 to 50 spam posts a day. Unless anyone who posts yet another link to this statement can provide a good scientific reason for doing so, beyond the (mostly non-scientific) reasons in the dozens of posts which already link to it, I think the time will soon come to start treating it as spam.

Do you have any idea how many times I'm handed the same links to the same papers over and over again?

The point I was making is that many "professional astronomers" do not agree with where "modern astronomy" has gone in recent years. I am not alone in my perception that "dark" things and mythical forces have become gap fillers (they called them fudge factors) and these gap fillers lack any real empirical evidence. IMO they are becoming increasingly embarrassing to a field of science that needs to embrace the role of current flows in space.

So you have said, numerous times.

I'm not alone in that assessment. It's a growing trend IMO and it began long before I personally ever got involved in it.

That may, or may not, be so.

It is also irrelevant ... if you have a viable alternative, please get it published (in a relevant, peer-reviewed journal).

If you know of a viable alternative that has been published, please provide a reference.

If you have neither, then please do not keep repeating what is essentially just your personal opinion.

[Nereid]

Michael made the same, basic, mistake earlier ... this assumes that the bulk of the mass of rich clusters is in the form of stars.

No, the mistake is Nereid's. They significantly underestimate the mass of the stars, and they overestimate the ionized gas between the solar systems. Those lensing papers do demonstrate one thing very clearly. The "missing mass" tracks with the infrastructures of the galaxies themselves, not with the gas between the solar systems.

Really?

Please provide some relevant references.

If you cannot, please do not continue to post what is, essentially, just your personal opinion.

[Nereid]

[snip]

Sun,

Estimates of the sun include not a single mention of any of the dark forces that supposedly make up 96% of the universe. Don't you find that a bit suspicious that dark matter is somehow 5 time more abundant than the mass in our solar system, and yet supposedly has zero effect on the solar mass?

Michael, if you do not understand what I have written, please ask for clarification.

I asked you at least once before to not put words in my mouth; I will ask you, again, politely: please do not put words in my mouth.

Specifically, wrt the part of your post I am quoting: if you would like a worked, OOM, calculation of the estimated density of DM (or DE) within the Sun, I (and, no doubt, several others who post here) would be more than happy to oblige.

If you would like details on the uncertainty with which we can, and have, measured the mass of the Sun, please just ask.

Above all, please cease this thoroughly anti-scientific 'incredulity' approach.

I, and many others, have stated, many many many many times that astronomy is a quintessentially quantitative science. If you can demonstrate, by even an OOM (order of magnitude) calculation, that the Sun should comprise a measurable quantity of DM or DE, then please so do.

Again, please do NOT continue to present arguments that contain no justified, quantitative, basis where the quantitative inputs to make a case are both widely available and well-understood.

stars in binaries, SgrA*, etc, etc, etc are blind to the composition of the bodies ...

How are stars in binaries blind to the composition of the bodies? How do you know how much mass either of them contains?

How come there is no mention of 96% of the universe when it comes to these calculations?

See above.

Also, if you'd like a simple tutorial on how the mass of stars (and SgrA*) can be estimated (and how well-constrained those estimates are), please just ask.

Please do NOT make (non-scientific) assertions concerning standard astronomical techniques ... unless you are prepared to defend such assertions with specific, pertinent references.

[Nereid]

You don't need to go to rich clusters to find good observational evidence that is inconsistent with this idea - the ISM and IGM (inter-galactic medium)/ICM (intra-cluster medium) are both more massive than the stars in (cluster) galaxies, and are composed almost entirely of H and He.

This part is "partially" correct. H and He are the lightest of the elements and therefore they escape the gravity wells of stars far more easily than iron, or nickel. They are therefore very abundant in the areas between stars.

The exception of course is the supernova event, in which things go "boom" and all the materials go flying, except for whatever lies at the remaining core. The remaining core in such an event is not likely to be H or He. The heavier elements released in such explosive events would be more apt to form new stars than any of the hydrogen or helium released in such an event.

In no mass separated solar scenario would it be at all surprising that H and He are the more abundant gases between the stars, but that says nothing about the composition of the stars themselves.

And what relevance does this have in this, a thread about DM?