Astronomy and "controlled scientific tests"

[Maddad]

Hey guys, let's be careful about being too aggressive. I attend another board where watching the personal attacks have become unpleasant. It is much worse than here, and yet it started much this way. We don't need to go there.

Nereid
You raised some good objections to my comments. More than good actually; some were outstanding. About ten days ago on a Wednesday I was composing a response when I had to leave for a medical checkup forty miles away. I still have those notes, and had planned on finishing that night. The doctors though decided to keep me, so I spent several days in the hospital on intravenous steroids. I am still on a taper to come down off them. I will finish my response and reply. I promise. And I will not attack you personally even though I disagree with you. If I do. Actually, you have not yet said anything with which I really disagree.

I'll talk about it tonight.

[makc]

...I'd be happy to let you use that technique to decide between competing theories that are grounded in known physics and known laws of physics.

What constitutes "known physics"?

What are the "known laws of physics"?

How are these established?

Is the theory of General Relativity (GR) "known physics"? Is it a "known law of physics"?

How about the Standard Model (of particle physics)?

put against Michael's latest reply,

I don't have any problem allowing you to speculate about entities that are know to exist and can be experimented with here on earth. I have a much tougher time with you simply making up energy fields and mass types without a shred of evidence such things exist or could or would have any effect on distant objects. There is a distinct boundary that you are trying to cross here...

I think Michael says that he will have no problem with any theory grounded on concepts that allow at least one experiment involving them here, on Earth.

Therefore, I think, Michael should have no problem with GR because it deals with "mass", a concept probably as old as physics itself (or at least as old as 1st conservation law).

[Nereid]

Where, as in - in which country/town/lab - can one go to observe the (observed) spectrum of the Sun created from an object (in this lab) called "a mass separated sun"?

You can't. I'm not however proposing any new "entities" here Nereid. All I'm suggesting is a different configuration of known entities. Compare and contrast that now with claiming that a big bang happened because of "Larry" energy, "Curly" energy and "Mo" invisible matter.

Getting closer ...

So, to turn up the contrast, we have two views of the science to be used to account for a number of well-observed spectral lines*.

In standard astrophysics, these lines are forbidden transitions, whose wavelengths can be accurately calculated from atomic quantum theory. The reason why they cannot be observed in earthly labs is also well-understood - the conditions under which they arise cannot be produced in any earthly lab (yet).

In MM astrophysics, these lines have an unknown origin, they are a mystery without explanation, because no one has been able to produce such lines in any earthly lab.

In standard astrophysics, detailed observations of these lines can be fed back into the quantum theory of the atom, and in turn be used to account for other astronomical observations, to test that theory, to predict lines which may be observed in certain experiments that could be done in earthly labs (but have not yet been done), and so on**.

In MM astrophysics, none of this can be done; as the lines are a mystery, no inferences may be drawn from their existence. Further, quantum theory of the atom is only valid in respect of what can be confirmed in lab experiments. And so on.

Perhaps I misunderstand MM astrophysics?

*Quite a few to choose from; perhaps one of the prominent forbidden lines in the visible waveband will do.

**One of the astronomical tests of the cosmologically important question of the possible variation in the fine structure constant, over cosmological time, used just this approach. [Edited to add the link to the Bahcall paper]

[Nereid]

[snip]

once you abandon an insistence that everything in astrophysics be reproduced in an earthly lab before it can be accepted, and accept a cosmological principle (crudely, 'if the spectrum has H, O, and S lines in it, then the distant object contains H, O, and S'),

I do accept we can't test all scientific ideas.

Which is, as I'm pretty sure you are very well aware, not a paraphrase of what I wrote ...

As I said earlier, once you let the genie out of the bottle (e.g. you cannot reproduce the observed spectrum of the Sun, in any earthly lab), you must - logically - declare all astronomy (beyond the solar system, closer to the Sun than any Mariner probe went, etc) a-scientific ... or develop different (scientific) criteria ... or adopt multi-tiered science (e.g. 'the only thing we can say - scientifically - is that {nebula} may contain H, O, and S, in some form'; however, 'this fish contains H, C, O, N, ...').

And since this forum is about astronomy (especially that beyond the solar system), it would seem there's little in the way of any meaningful (science-based) communication we could possibly have, is there?

the only place you have to run - as far as I can see - is the denial that quantitative detail in astronomical data can provide a legitimate constraint on any theory whose domain of applicability includes the objects under study.

I'd be happy to let you use that technique to decide between competing theories that are grounded in known physics and known laws of physics.

What constitutes "known physics"?

What are the "known laws of physics"?

How are these established?

Is the theory of General Relativity (GR) "known physics"? Is it a "known law of physics"?

How about the Standard Model (of particle physics)?

What you can't do however is simply invent things like invisible unicorns, assign physical properties to invisible unicorns, create a bunch of math related to unicorn theory, and then try to use those distant measurements to tell if your unicorn theory is valid!

What's the difference between one unicorn ('that nebula contains H, O, and S') and another ('that galaxy cluster contains 10^n sols of dark matter')?

Remember that you need at least some unicorns (a.k.a. 'a leap of faith'), if only because you can't reproduce the spectrum in your lab.

Welcome to degenerate matter,

Maybe.

[snip]

Hmm ... you do realise, don't you, that your PC requires degenerate matter to run properly?

I hope you'll get around to addressing the rest of this post sometime soon Michael.

I think we are very close to describing the gulf between the limited view you have of the scope of modern astronomy and that of modern scientists (astronomers), and so will be able to properly contextualise any future posts you may make in this forum.

[Nereid]

Therefore, I think, Michael should have no problem with GR because it deals with "mass", a concept probably as old as physics itself (or at least as old as 1st conservation law).

I don't have any problem with GR, just as long as you stick with Einstein's version, and don't start trying to resurrect the "greatest blunder" variety and then try to make it do Gumby tricks with metaphysical entities.

Take a high-quality astronomical observation of a rich cluster - Abell 1689 for example - apply GR (gravitational lensing, in this case), turn the handle, and out will pop an estimate of the mass of the cluster (plus the distribution of that mass).

Take high-quality x-ray observations of rich clusters, apply standard (plasma) physics, turn the handle, and out will pop an estimate of the mass of the clusters (plus the distribution of that mass), and an estimate of the mass of the x-ray producing plasma in those clusters - Abell 2029, for example.

The (total cluster) mass estimates agree ... and they are much larger than the estimated mass of the hot plasma which generates the x-rays (which in turn is much greater than the estimated mass of the component galaxies).

Take detailed spectroscopic observations of the individual galaxies in the cluster, apply standard (Newtonian) physics (to the individual galaxy redshifts), turn the handle, and out will pop an estimate of the total mass of the cluster - the Coma cluster, for example.

The (total cluster) mass estimates agree ... with both the above approaches, even though this one pre-dated the other two by many decades.

What is the invisible matter which makes up the bulk (~85%) of the mass of these rich clusters?

[Nereid]

Take a high-quality astronomical observation of a rich cluster - Abell 1689 for example - apply GR (gravitational lensing, in this case), turn the handle, and out will pop an estimate of the mass of the cluster (plus the distribution of that mass).

Based on a non mass separated hydrogen sun theory? Do you really think that I personally put any confidence at all in that distribution number you're tossing at me?

I didn't think, after harry stopped posting, I could be really surprised by any posts here in the Cafe ... I was wrong - this one was quite unexpected!

Michael, this is, as I have said, many times, a scientific forum.

If your pet 'iron suns' idea has legs, it will have been published in a relevant, peer-reviewed journal.

If there are such papers, showing that the mass distribution - from analysis of gravitational lensed objects such as in Abell 1689 - is consistent with this 'iron suns' idea, please provide the appropriate references.

Until then, please stop using this Cafe as a place to promote this unsubstantiated idea.

What is the invisible matter which makes up the bulk (~85%) of the mass of these rich clusters?

It's found inside all those mostly iron suns IMO.

Leaving aside, for now, you personal opinion; can you cite papers, in relevant peer-reviewed journals, which account for this (~85%) cluster mass as "iron suns"?

If not, then please do not refer to this idea, in this context, in the Cafe, again.

[makc]

Don't you just love this:

What's the difference between one unicorn ('that nebula contains H, O, and S') and another ('that galaxy cluster contains 10^n sols of dark matter')?

I can hand you a gram of H,O, and S, that's the really obvious difference.

The Q. and the A. are 167 posts apart. Even in this thread, it takes a lot of scrolling and reading to track this. The debate is obviously overheated.

Michael: to the question on what's wrong with the concept of "matter that we can't hand you". Why does this "matter" have to exist in a handable form? Let's consider Nereid's post 58101 for a second. We had a theory you say is ok, we apply it, and we see that it doesn't work... unless there are unacconted factors in the problem. Math says that there are probably thousands of ways to take these factors into account (maybe even including your iron Sun theory), but the simplest way is to add some mass into equation. At this point, we don't know what that extra mass is or, if you insist, we don't even know if there is extra mass in some specific form (like undetectable magic black zetta betta petta abra cadabra particles), but we DO know that there is a factor that under present theory can be best accounted for by extra mass.

So, what's wrong with putting "dark matter" label on it? Do you feel like term "matter" is not wide enough to embrace math trick described above?

Think about space and time. You can't feel these. You can't "hand" these to someone. You can't carry some of these in a pocket. As they are, they are imaginary, pure mathematical concepts that, for now, are best fit to describe the way things we do feel, can "hand" to someone and carry in a pocket, behave.

Same with "matter". It is the concept. We have invented it. We have constantly changed it through the past (from four elements to standard model). In fact, this word can mean whatever we want. Perhaps, it is too much for one word already, and they need to come up with some other name than "dark matter" to make people more receptive?

[BMAONE23]

"Unidentified Matter", IMO, would be a great label to place on it. Dark Matter does tend to describe it in a fashion that implies it has been directly viewed when only the gravitational effects of an unseen mass has been recorded.

[Nereid]

What constitutes "known physics"?

Known physics is something I can play with in a lab and duplicate in a lab.

Didn't you give your "OK" to GR, a few posts back?

How much of GR can you test, in controlled experiments in earthly labs?

And then there's forbidden lines, line profiles, relative line strengths, ...

Can you elaborate on the apparent disconnect here please?

What are the "known laws of physics"?

Well, the conservation of energy law is the one that blows holes in your inflation idea, not to mention that small problem of mass ending up more than 27.4 light years from any other mass.

Hmm ... both GR and quantum mechanics violate this "conservation of energy law" - how are these violations handled, in your view of 'laws' and science?

How are these established?

They were established by careful analysis in *controlled* conditions.

See above - what are the *controlled* conditions in which GR was established?

Is the theory of General Relativity (GR) "known physics"?

The GR Einstein taught is, yes, but not that "greatest blunder" Gumby-Lambda thingamamabob.

So you have no problems with neutron stars and black holes?

Nor with the fact that energy is not (generally) conserved, in GR?

Is it a "known law of physics"?

No, it's a theory, but a good one, and a well tested one.

What's the difference between a law and a theory?

How about the Standard Model (of particle physics)?

Everything up to the Higgs boson is just fine by me because we've been able to detect pretty much every other particle described by particle physics. The Higgs boson may or may not exist for all I know. Most of the rest of the theory is predicated that very small particle that has mass, and we have some idea of it's energy state based on other aspects of particle theory. We can also jump up and down and experience gravity for ourselves. Whether or not the Higgs boson exists I cannot say, but I have no problem with it, only because there are ways to look for it, and to falsify it.

Degenerate matter is OK then?

Neutron stars?

Standard stellar models?

So we *can* say that {forbidden line in astronomical spectrum} is due to {transition of common atomic species, such as O}? Even though no one has ever observed any such in any earthly lab?

What's the difference between one unicorn ('that nebula contains H, O, and S') .....

Er, I assume this goes back to your forbidden line thing again? You act as though that is the *only* way we can tell what a nebula is made of.

It's a question of what gives rise to the line ... and the fact that Michael cannot take me to a lab, anywhere on Earth, where they can create such a line ...

Or, more fundamentally, it's about establishing the extent to which your view of astronomy, as a science, is internally consistent ...

and another ('that galaxy cluster contains 10^n sols of dark matter')?

I can hand you a gram of H,O, and S, that's the really obvious difference.

Is this an answer?

I hope you'll get around to addressing the rest of this post sometime soon Michael.

Was there anything I missed that is critical for me to answer for us to continue our discussion?

I think we are very close to describing the gulf between the limited view you have of the scope of modern astronomy and that of modern scientists (astronomers), and so will be able to properly contextualise any future posts you may make in this forum.

You are going to have to acknowledge the difference between using known forces of nature to describe distant events, and blaming those same distant events on something that is not known to exist in nature and cannot be shown to exist in nature.

Here's the bottom line on this Michael: the engine room of science is theory generation and testing ... the way astronomy, as a science, works is (to a large extent) based on explaining good observational results within the framework of theories that are internally consistent, and consistent with other, well-established theories where their domains of applicability overlap.

AFAIK, there are no good, scientific, alternatives to LCDM cosmology, and to DM being the dominant form of matter in rich clusters (etc).

In many threads in this Cafe you have been given the opportunity to reference such alternatives, in terms of papers published in relevant peer-reviewed journals.

You have been unable to provide any such references.

In this thread, you have been given an opportunity to explain your view of astronomy as a science, and, in particular, how it operates consistently.

I think, from the post of yours that I'm quoting, and others, it's clear your approach is quite at odds with that used by modern astronomers.

[makc]

Think about space and time. You can't feel these.

Not that I mean to quibble here, but actually I can.

Wow, you must be really special then I mean, N thousands of years before noone could, obviously; probably, we owe every bit of geometry to these new senses selected individuals have developed since then.

How much of GR can you test, in controlled experiments in earthly labs?

Pretty much all of it, inasmuch as it subsumes newtonian theory. The gravity is right here all around us, and the fact that you can't have as much precision in your lab as you would like to, is irrelevant.

[Nereid]

[snip]

How much of GR can you test, in controlled experiments in earthly labs?

Pretty much all of it, inasmuch as it subsumes newtonian theory. The gravity is right here all around us, and the fact that you can't have as much precision in your lab as you would like to, is irrelevant.

Good point.

Maybe I could try a slightly different question: How much of the difference between GR and 'Newtonian gravity' phenomenology can you test, in controlled experiments in earthly labs?

And a more restrictive question still: How much of GR's 'strong field'* aspects can you test, in controlled experiments in earthly labs?

Off the top of my head, I can think of one 'lab on Earth' controlled ('GR vs Newton') test: the Pound-Rebka experiment.

*If any reader is unsure what this refers to, please just ask!

[Nereid]

Michael: to the question on what's wrong with the concept of "matter that we can't hand you". Why does this "matter" have to exist in a handable form?

The thing that we claim has this effect on a distant event has to be known to exist in nature. It's absolutely fine and logical for us to posit theories about things that are known to exist in nature, even if we can't touch them because they are 5 billion light years away, and even if our theory turns out to be incorrect.

What we can't do is claim that invisible things did it, and not be able to demonstrate that these invisible things actually exist in nature.

"Hydrogen did it" is a logical theory, even if it's wrong. "Invisible stuff did it" is not a logical theory because we must first demonstrate that invisible stuff exists and can have the effect we claim it can have.

This is a pretty succinct encapsulation of the difference between what seems to be your view of how the science of astronomy works and how, to the contrary, it does actually work.

However, to see the difference more clearly, you need to turn the statements upside down; something like this:

All scientific theories rest on postulates. Postulates are "invisible things".

Good scientific theories develop conclusions by building logically from the postulates (what I have called 'internal consistency'); by ensuring there are no conflicts with other, good, scientific theories, where such theories overlap (what I have called 'consistency with other, well-established theories where the domains of applicability overlap'); and by demonstrating acceptable* correspondence - nearly always quantitative - between phenomenological conclusions and good experimental and observational results (you can fill in what I called this elsewhere).

One corollary to this is that the existence of 'invisible things' (the postulates, and other non-observables derived logically from them) is only as good as the extent of the correspondence with observations. In modern science (physics, astronomy, cosmology, ...), 'electrons' and 'space' and 'energy' and ... are theoretical entities, "invisible things" whose characteristics (nature) are (is) either postulated or derived from postulates.

So, what's wrong with putting "dark matter" label on it? Do you feel like term "matter" is not wide enough to embrace math trick described above?

They didn't just put a label on it, they started ascribing properties to it. In other words, rather than referring to it as an "unidentified mass", or "unidentified matter", it became invisible, non baryonic mass, able to pass through walls at will.

By turning this on its head - which is what you need to do to give it the correct, scientific, characterisation - I think you'll see where you've gone wrong.

This now precludes us from entertaining other possible options, like current flow, and iron suns, etc.

Just the opposite in fact.

The characterisation of (most of) the inferred DM as non-baryonic came as a consequence of repeated, consistent failure to account for several different kinds of good, repeated observations using a "hydrogen did it" approach.

A corollary is that if an alternative - current flow, iron suns, TeVeS, unicorns - comes along which can account for the relevant good observations, then it will be paid serious attention. Of course, the other two criteria must also be met - internal consistency (that's why the first Thieu and Cooperstock paper went nowhere) and consistency with other, well-established theories (that's where MOND falls off the rails - it does not incorporate relativity).

However, in astronomy, the observations rule.

In fact if Nereid has her way, I'm never to talk about them again here. That kind of narrow mindedness is dangerous IMO, and it can lead to unforeseen consequences.

[snip]

When you can demonstrate that these things meet the three criteria - especially the one about quantitatively accounting for the relevant observations - then you may talk about them.

After all, this is a scientific forum.

In shorthand, within the error bars of the observations.

[Nereid]

This is a pretty succinct encapsulation of the difference between what seems to be your view of how the science of astronomy works and how, to the contrary, it does actually work.

Ok.

However, to see the difference more clearly, you need to turn the statements upside down; something like this:

All scientific theories rest on postulates. Postulates are "invisible things".

No. You'll have to start with a better argument. Postulates can be lots of things. They need not be invisible.

Good ... the gulf between modern astronomy as a science and your own view is, as I suspected, quite large.

Let's take the two most general and most successful theories in modern physics - General Relativity, and the Standard Model.

Each rests on a set of premises (postulates) from which various conclusions are (logically) derived (including all the phenomenology).

Which of the premises of these two theories are "visible"?

One corollary to this is that the existence of 'invisible things' (the postulates, and other non-observables derived logically from them) is only as good as the extent of the correspondence with observations. In modern science (physics, astronomy, cosmology, ...), 'electrons' and 'space' and 'energy' and ... are theoretical entities, "invisible things" whose characteristics (nature) are (is) either postulated or derived from postulates.

Such "postulates" as you call them are only as good as the evidence to support them. We can test for the existence of electrons and neutrinos in very controlled and precise ways today here on earth. Why can't you do that with dark matter? I'll tell you why. You can't do that because you really A) don't know if it even exists, and B) you don't know where it comes from.

In view of how large this gulf* seems to be, it may be worth spending some little more time on it.

However, as it's only tangential to astronomy, it might be a good idea for you to find some other fora where you can explore the nature of modern physics (and science in general) in more detail ...

As I said above, modern scientific theories - as logical constructions - begin with premises, or postulates. What's tested is not (generally) the postulates, but the directly observable, predicted phenomena that follow by developing the theory in a logical fashion.

Of course, historically, the first form in which a theory is published may differ considerably from its later form - this is particularly true of General Relativity.

Take "the equivalence principle". Einstein's original formulation is: "we [...] assume the complete physical equivalence of a gravitational field and a corresponding acceleration of the reference system." (note that it is full of 'invisible things'!).

Today there are three equivalence principles in use (note that they, and GR, have been reformulated since the first publication of GR, to facilitate testing, among other things):

the weak: "All bodies at the same spacetime point in a given gravitational field will undergo the same acceleration"

the Einstein: "the result of a local non-gravitational experiment in an inertial frame of reference is independent of the velocity or location in the universe of the experiment"

the strong: "the results of any local experiment, gravitational or not, in an inertial frame of reference are independent of where and when in the universe it is conducted"

What's interesting to note is that experiments and observations to find any deviations from the inverse square law are tests of the strong equivalence principle (do you see why?).

To re-iterate: the way astronomy, as a science, works is through theories. Theories are logical constructions, resting on premises, which can be worked with to produce (logically consistent) conclusions. It is these conclusions that are tested, directly, by experiments and observations. Failure to match experimental or observational results is the most powerful method of invalidating a theory.

So, wrt 'dark matter', you can most powerfully knock it out by showing that predictions derived logically from the premises are inconsistent with good observations or with experimental results.

It follows that many - perhaps most, or even all - of your objections to 'dark matter' are not, in fact, scientific objections at all.

Why? Because they are not related to either the premises or conclusions of any 'dark matter theory'.

Specifically, if any such theory is silent on the nature of DM (other than that it is a form of mass-energy and does not interact with photons), then your inability to buy a gram of it at your local Tesco is irrelevant.

This lack of understanding you have about the very nature of your presumed dark matter precludes us from even devising legitimate controlled tests to find them. With the neutrinos experiments, we put our detector next to a nuclear reactor and turned the reactor on and off to make sure it was in fact the source of neutrinos, and we were really detecting neutrinos. What is the source of dark matter?

Good questions all.

However, as I think you are now beginning to see, also irrelevant, in a narrow sense, to any 'dark matter theory'; specifically, DM in modern astronomy (and cosmology) is not presumed to have any particular origin (though many folk are working on it!), beyond that it existed in its present (cold, mass, non-interaction with photons, etc) form well before (baryonic) matter and photons decoupled.

They didn't just put a label on it, they started ascribing properties to it. In other words, rather than referring to it as an "unidentified mass", or "unidentified matter", it became invisible, non baryonic mass, able to pass through walls at will.

By turning this on its head - which is what you need to do to give it the correct, scientific, characterisation - I think you'll see where you've gone wrong.

I'm sorry, I don't see it. You started ascribing properties to something that is billions of light years away. You can't actually see that far with your equipment, and you can't even 'see' your presumed dark matter with your equipment in the first place according to your theory. It's a circular feedback loop. You do not know if that missing mass is related to heavy suns/solar systems or dark matter, you simply choose to put faith in something that has never been shown to exist or have any effect on matter or light in any controlled scientific test. Why?

Hmm, ... it seems you've missed the parts about consistency ...

Take the large body of good astronomical observations as input.

Your challenge is to account for them in a consistent fashion.

For rich clusters, there are several sets of independent observations, based on quite different physical mechanisms.

If you postulate 'cold dark mass', you get a very pleasing consistency.

If you postulate anything else (that I'm aware of), you don't get any consistency worth writing home about.

Specifically, "heavy suns/solar systems" are very easy to rule out ... the missing mass is dark, and it's not in the galaxies in the rich clusters (it has a more or less radial density profile, with a peak near the central cD galaxy/galaxies).

Of course, if these "heavy suns/solar systems" do not emit light, nor explode as supernovae, nor generate winds (of H, He, etc), nor ...

This now precludes us from entertaining other possible options, like current flow, and iron suns, etc.

Just the opposite in fact.

How's that? You've basically ruled out any idea you've never seen in print before. You've even somehow in your head ruled out solar theories put forth in the papers that Dr. Manuel and Hilton and I got published over the last two years as well. According to you, the idea has to be found in the "right" (lingo for mainstream) publications, or you refuse to consider them. Heavy solar systems would eliminate the need for dark matter entirely.

[snip]

Now THAT is what I call a pretty dramatic claim!

Would you care to start a new thread whose specific and focussed objective is to present quantitative details of such a claim in regards to the three sets of astronomical observations of rich clusters that I have mentioned earlier?

A corollary is that if an alternative - current flow, iron suns, TeVeS, unicorns - comes along which can account for the relevant good observations, then it will be paid serious attention.

If that were true, you'd be on my side by now, because I'm quite sure that you personally and nobody else here on this forum can explain that very first Lockheed Martin Running difference image on my website using gas model theory. It's never happened in two years of online debates, and most people run for cover when I ask them for an explanation of that specific solar image. Care to be the exception to that rule Nereid?

[snip]

Let's stick with theme of this thread, shall we?

In which lab, on Earth, may one see a reproduction, under controlled conditions, of the {Michael Mozina idea}? Specifically, running difference images identical to the LM running difference ones?

[Edited to add the missing footnote:
*or how comprehensive the misunderstanding of the nature of modern astronomy seems to be.]

[Nereid]

Good ... the gulf between modern astronomy as a science and your own view is, as I suspected, quite large.

I think we all agree that is so. I'm not as big of a believer in the metaphysical side of life as you are.

Please, do not put words into my mouth.

Let's take the two most general and most successful theories in modern physics - General Relativity, and the Standard Model.

Each rests on a set of premises (postulates) from which various conclusions are (logically) derived (including all the phenomenology).

Sure, but that is not true of every part of every theory, nor is every single postulate of every single scientific theory "invisible".

If you know of any successful modern theory, used in astronomy as a science, which can be shown to be independent of these two, please do tell us (you would have the undivided attention of tens of thousands of physicists, as well as astronomers).

Absent such a theory, we could summarise by saying that all modern astronomy rests on (is derived, logically, from) postulates that are "invisible".

Which of the premises of these two theories are "visible"?

I can see that electrons are powering my computer right now. How about you? I've never seen any evidence that dark thingies exist, let alone that they could be useful in my daily activities. Particle physics has produced some very helpful and useful and tangible assets in my world. What has dark matter or dark energy or inflation done for me lately?

(my bold)

You can?!?!?!?!?

How?

Such "postulates" as you call them are only as good as the evidence to support them.

Indeed ... that's what I said.

We can test for the existence of electrons and neutrinos in very controlled and precise ways today here on earth. Why can't you do that with dark matter? I'll tell you why. You can't do that because you really A) don't know if it even exists, and B) you don't know where it comes from.

Hmm ... it seems that you're going to have to go elsewhere to continue this Michael ... the existence of 'electrons' and 'neutrinos' requires acceptance of a rather great deal of scientific theory. To see one reason why, ask yourself this question: "what is an electron?"

For more detail, read a standard textbook on (modern) particle physics, paying particular attention to the postulates of the Standard Model and the logic which gets you from those postulates to anything observable.

But, as I said, that's beyond the scope of this Cafe.

In view of how large this gulf* seems to be, it may be worth spending some little more time on it.

You could spend less time just by producing a gram of dark matter for us to inspect and play with in a lab. You could end this debate immediately by showing me one test where dark matter was shown to have an effect on reality. Why spend any time you don't need to spend on words, when a single piece of empirical evidence would do the trick?

You have already been presented with rather a large number of just such tests ... but, in a not-unexpected way, we're back where we started: 'forbidden lines' in certain nebular spectra do have 'an effect on reality' (if only the CCDs in certain astronomers' instruments), but you can't take anyone reading this post to any lab, here on Earth, where such can be produced.

However, as it's only tangential to astronomy, it might be a good idea for you to find some other fora where you can explore the nature of modern physics (and science in general) in more detail ...

I'm familiar with physics and science related to computers and computer software. I'm familiar with sciences that have a direct impact on my life. I'm familiar with plasma cosmology and it seems to have that kind of promise. In other words, I can envision a day when human beings build machines to ride the EM currents of space. That kind of technology could have a tangible effect on human beings. I can't even imagine them riding dark stuff, because I have no evidence that any dark stuff exist in the first place.

As I said above, modern scientific theories - as logical constructions - begin with premises, or postulates. What's tested is not (generally) the postulates, but the directly observable, predicted phenomena that follow by developing the theory in a logical fashion.

You created a postulate that goes something to the effect:

"I have faith that some distant observation is due to an invisible thingamabob that is able to pass through matter at will. But then I'd also like to throw in an asterisked disclaimer at the bottom of my theory because it may be due to something else altogether."

If you think that's what I've been saying, then I doubt there's much point in continuing this discussion.

That isn't a scientific explanation Nereid, that is a giant leap of faith into metaphysics, with a huge loophole of a disclaimer to boot!

Of course, historically, the first form in which a theory is published may differ considerably from its later form - this is particularly true of General Relativity.

Einstein called your variation of GR theory his "greatest blunder". I have have no reason to doubt his assessment of any GR theory that gets turned into Gumby through the introduction of metaphysics.

[snip]

Again, please do not put words into my mouth.

Again, if this is what you think I've said, then it seems this thread has run its course.