Fermi and dark matter

No, it's that electrical discharges are already a known and demonstrated source of gamma rays on Earth, and gamma rays around larger bodies in the solar system. What do we need dark energy for?

[...]
Indeed.

But do the numbers add up?

Or is it - once again - a case of "who the **** cares about ****ing numbers! :mad:" ?

In short, have you not, for the umpteenth time, demonstrated that the MM worldview is blind to quantitative analyses? Or, to be blunt, that your approach is antithetical to science?
 
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Well it doesn't unify the three non-gravitational forces. It doesn't really explain the neutrino masses. And it does contain quite a few free parameters.

Fair enough. I think most folks figure that will come about via QM sooner or later. How does SUSY theory solve any of those issues?

I'm going to skip the irrelevant stuff if you don't mind.

I personally had no evidence for the existence of the top quark in the early 1990's. What's your point?

My point is that even in the early 1990's there was a 'likelihood' that it would be found. There is no such likelihood as it relates to SUSY theory. I guess I may not understand what specific issue you believe SUSY theory will solve and I probably need to hear that answer before I can continue.

And you think there is no evidence of gamma rays from high-energy particle interactions?

Sure. I don't have any problem with you attributing gamma rays to anything that can be empirically demonstrated.

Where? Either you have a quantitative model to defend or you have nothing. Which is it?

http://www.sciencemag.org/cgi/content/summary/307/5712/1054

If you mean have I personally sat down to explain the Fermi data with electrical discharges and known solar activities, no, I have not done that. I haven't even seen a full solar cycle in Fermi data yet, so how would I know what is "normal" output for our own sun?
 
Please define "electricity".

Inside a mostly plasma universe is I would describe it as "current flow". Moving ions can contain a charge as well as electrons, and protons.

Even if this were the case, still doesn't explain galactic rotation curves. Oh and I'm expecting to see a full quantitative explanation of the data. SInce you are so sure you're right that must be pretty straightforward.

I'm willing to accept that there is "missing mass" in a galaxy that our current mass estimates cannot account for based on the lensing data I have seen. I therefore prefer a "missing mass" theory over a MOND theory for instance. That does not mean that any of the "missing mass" in located in any form of exotic materials that do not show up in particle physics experiments and/or the periodic table.

What are you talking about? My argument was that your assertion that dark matter didn't exist because it hadn't been seen in a lab was, based on history and common sense, a ridiculous one. This has nothing whatsoever to do with Occam's razor.

I'm saying that there is already a known and demonstrated "natural" way to generate gamma rays. There is no need for DM. It's not going to survive an Occum's razor argument.
 
Indeed.

But do the numbers add up?

Or is it - once again - a case of "who the f*** cares about f***ing numbers! :mad:" ?

In short, have you not, for the umpteenth time, demonstrated that the MM worldview is blind to quantitative analyses? Or, to be blunt, that your approach is antithetical to science?

I guess if I *had* to choose between the two, I'd rather be blind to the quantitative analysis than to be blind to the qualitative analysis like you. :)

How exactly would you suggest that we go about computing a number of photons counts to expect from a sun and from the planets when we haven't a full solar cycle to work with?

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Have these more recent discoveries even been factored into current galaxy estimates in terms of the number of stars there are in a given galaxy, including our own? How many gamma ray emitting planets shall we assume for every star in your opinion?

I know how much you love to simply ignore the qualification side of empirical physics and all that matter to you is the math, but don't you get tired of just pulling these numbers out of thin air and then seeing them be demonstrated to be wrong over and over again?

From a 'qualitative" side of science, you haven't a leg to stand on and your math is just fancy window dressing. It's still just mathematical lipstick on a metaphysical pig.
 
Fair enough. I think most folks figure that will come about via QM sooner or later.
Such as supersymmetry.

How does SUSY theory solve any of those issues?
It allows the coupling constants of the three forces to meet at a single distance/energy scale which would allow for a "natural" GUT. I guess this would also lead to less free parameters although I'm a little rusty here.

My point is that even in the early 1990's there was a 'likelihood' that it would be found. There is no such likelihood as it relates to SUSY theory.
Best tell all those people at CERN who are wasting there time then. They certainly seem to believe its a distinct possibility.

I guess I may not understand what specific issue you believe SUSY theory will solve and I probably need to hear that answer before I can continue.
Google it. I'm sure you can find better sources than me.

Sure. I don't have any problem with you attributing gamma rays to anything that can be empirically demonstrated.
But a number of these things were empirically demonstrated from measuring the gamma-rays in the first place! If you rule out the empirical evidence that something exists based on the fact that its never been shown to exist before then you're never going to discover anything new at all.

I can't read the paper. But based on the abstract, the phenomena described are too low in energy by a factor of at least 50 compared to the data in the FGST paper. So I'm not sure what the relevance is.

If you mean have I personally sat down to explain the Fermi data with electrical discharges and known solar activities, no, I have not done that. I haven't even seen a full solar cycle in Fermi data yet, so how would I know what is "normal" output for our own sun?
I'm not sure why you need a full solar cycle.
 
Inside a mostly plasma universe is I would describe it as "current flow". Moving ions can contain a charge as well as electrons, and protons.
So what did you mean by
If we need more of them, all we have to do is turn up the "electricity" and a known source of gamma rays in nature will produce more gamma rays.
?

I'm willing to accept that there is "missing mass" in a galaxy that our current mass estimates cannot account for based on the lensing data I have seen. I therefore prefer a "missing mass" theory over a MOND theory for instance. That does not mean that any of the "missing mass" in located in any form of exotic materials that do not show up in particle physics experiments and/or the periodic table.
Actually it does, precisely because of the successes of the Standard Model. It cannot be explained by anything that interacts electromagnetically. That leaves neutrinos. But neutrinos are too light.

I'm saying that there is already a known and demonstrated "natural" way to generate gamma rays. There is no need for DM. It's not going to survive an Occum's razor argument.
a) This was not my argument (not at the time anyway).
b) There is from the galactic distribution curves etcetera.
We have no simple explanation of the source of the gamma rays. You are unable to provide a quantitative explanation. And neither has anybody else.
Therefore dark mater is a possibility. But even if its something more mundane there's still those galactic rotation curves, those cluster rotation curves and various other things supporting the existence of DM.
 
I guess if I *had* to choose between the two, I'd rather be blind to the quantitative analysis than to be blind to the qualitative analysis like you. :)

How exactly would you suggest that we go about computing a number of photons counts to expect from a sun and from the planets when we haven't a full solar cycle to work with?

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Have these more recent discoveries even been factored into current galaxy estimates in terms of the number of stars there are in a given galaxy, including our own? How many gamma ray emitting planets shall we assume for every star in your opinion?

I know how much you love to simply ignore the qualification side of empirical physics and all that matter to you is the math, but don't you get tired of just pulling these numbers out of thin air and then seeing them be demonstrated to be wrong over and over again?

From a 'qualitative" side of science, you haven't a leg to stand on and your math is just fancy window dressing. It's still just mathematical lipstick on a metaphysical pig.
So tell me, MM, what was the proper - i.e. kosher according to the MM worldview of science - thing to have done wrt the original dark matter (i.e. Neptune)?

And would you have railed vociferously against all those who sought to test GR (the solution to the second lot of solar system dark matter, a.k.a. the anomalous advance of the perihelion of Mercury), because it had not been demonstrated in any earthly labs?

Wrt your quantitative questions: pick a number (or ten), MM, as long as it is consistent with all relevant observations, turn the handle, and produce for us an upper estimate of the gamma ray SED you'd expect Fermi to observe, from all the kings horses (the MW stars) and all the kings men (the MW planets).

And when you've done that, compare it to what Fermi has actually observed, write up your work, and submit the paper to ApJ (or similar).

Wait! You don't even need to do that ... the back of an old envelope would do, wouldn't it?
 
And since ordinary suns release these same exact gamma rays on a regular basis you have absolutely nothing to support your claim.
Stars do emit a small amount of gamma rays.
I do not make the claim that there is a Fermi haze. The paper does.
You make the claim that this invalidates the paper. Now give your evidence that it does.

So what? Based on what evidence? Point at the sky claims?
Based on actually reading their paper.

The fact that these authors make exactly the same mistake you're making doesn't justify the error.
What error? Citation please. Or a fully worked example of the gamma sources that they missed.
Their conclusion was that new physics (e.g. the decay or annihilation of dark matter) or new astrophysics is the mechanism producing the excess gamma rays.

So your original logic was wrong and there is no fallacy.

So suns are a perfectly "natural" source for such emissions and we have no need for anything exotic.
They are not a perfectly "natural" source for such emissions until you give evidence for that they are.

Uh, yes, but what does that have to do with anything? You asked for evidence that Fermi could see a sun. I provided that evidence. Gamma rays are definitely coming from our sun and likely all suns in the galaxy. It's hardly a surprise then when we can observe the galaxy in gamma rays in a Fermi image.
I asked for evidence that the Ferrm data sees gamma radiation from stars - a plural.


It is clear that stars emit gamma rays. We detect them from the Sun. The questions is:
  • Is the amount of gamma rays emitted by the stars in the galaxy large enough to be detected by Fermi?
My guess is no.
  • If it was then the NASA movie would show the stars moving, especially the nearer stars.
  • People who know about this stuff (unlike you and me, MM!), take account of strongly emitting objects like X-ray binaries, pulsars, etc.
    They then confirm that there is no contribution from other point sources to the spectrum of the Fermi haze .
Point sources in the paper :
In this fit, we mask out all of the Fermi 3-month point source catalog as well as the LMC, SMC,Orion-Barnard’s Loop, and NGC 5090.

Appendex A is all about the effects of unresolved point sources! This includes normal stars (AFAIK).
It concludes

As Fig. 13 shows, at low energies we find values of R consistent with a significant point source component (although the point source fraction cannot be precisely determined without knowing the luminosity function). Above 10 GeV, however, the value of R is consistent with entirely diffuse emission, and at 95% confidence, the fraction of emission from unresolved point sources cannot exceed ~ 5% and remain consistent with the measured value of R. Therefore,even for these conservative assumptions, the hard spectral shape of the Fermi haze cannot be caused by point source contamination.
 
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I don't know if anyone's mentioned this, yet, but the galaxy's star rotation indicates the existence of matter well in excess of that of adding up the mass of the stars.

Galaxies look like a bunch of stars swirling down a drain. In this case, the supposition is they're all in orbit, more or less, about the center of the galaxy, which has the vast bulk of mass, and thus gravity.

Except that when scientists measured how fast stars were going around the center of the galaxy, it was much closer to a solid disc rotating than a bunch of swirling stars.

The only way that can happen is if there's a lot more mass way outside the core of the galaxy so there's a counterpull of gravity that counteracts a lot of the swirliness. There isn't that much swirliness if you're being pulled from both sides almost equally.

Now stars are huge, and a hundred billion are a massive amount of mass, but it's no way near enough to account for that observed behavior.

SO, there must be a lot more mass, i.e. matter somewhere, but we can't see it, so "dark matter" it is. The rest so far is trying to derive characteristics of it -- doesn't interact with observable frequencies, etc.

Any ideas? Have fun! :) But it's not just pulled out of their ass. And other theories besides matter are being considered, I'm sure, from measurement errors to new forces that act on massive scales and so on.
 
I don't know if anyone's mentioned this, yet, but the galaxy's star rotation indicates the existence of matter well in excess of that of adding up the mass of the stars.

Galaxies look like a bunch of stars swirling down a drain. In this case, the supposition is they're all in orbit, more or less, about the center of the galaxy, which has the vast bulk of mass, and thus gravity.

Except that when scientists measured how fast stars were going around the center of the galaxy, it was much closer to a solid disc rotating than a bunch of swirling stars.

The only way that can happen is if there's a lot more mass way outside the core of the galaxy so there's a counterpull of gravity that counteracts a lot of the swirliness. There isn't that much swirliness if you're being pulled from both sides almost equally.

Now stars are huge, and a hundred billion are a massive amount of mass, but it's no way near enough to account for that observed behavior.

SO, there must be a lot more mass, i.e. matter somewhere, but we can't see it, so "dark matter" it is. The rest so far is trying to derive characteristics of it -- doesn't interact with observable frequencies, etc.

Any ideas? Have fun! :) But it's not just pulled out of their ass. And other theories besides matter are being considered, I'm sure, from measurement errors to new forces that act on massive scales and so on.

As I have explained in the past, due to the lensing data I've seen, the concept of "unidentified mass" or 'missing mass' is more appealing to me than say MOND theory.

IMO that simply demonstrates we grossly underestimate the amount of mass in a galaxy. Those links I cited for DRD demonstrate the recent discoveries suggest we have grossly underestimated the amount of dust in the universe as well as the number of smaller stars in a galaxy. Have these more recent discoveries even had a chance to be factored into our galaxy mass estimates?

The term "dark matter' as I was taught it in school was mostly though to be standard matter our technologies could not yet identify, more along the lines of MACHO orientation of 'dark matter". Today's new and improved brand is being created in an "ad hoc" manner and being assigned various "properties" that have never been demonstrated. The term "dark matter" has changed from being associated with standard material, to being mostly associated with hypothetical SUSY theory with hypothetical and metaphysical properties galore.

When we look at the Fermi images, the material doesn't seem to be concentrated in any one place around the galaxy, instead the entire galaxy seems to glow as though every star and every planet is emitting these wavelengths. That's confirmed too by the fact we can observe the sun traversing the Fermi data set quite clearly. It should hardly be surprising then that we see gamma rays from stars in a galaxy and even planets are known to emit gamma rays inside our own solar system.

There's absolutely no need for 'dark matter' to explain 'gamma rays' from a galaxy. There's no empirical link established between 'dark matter" and "gamma rays". The whole thing is "assumed", the material itself, the gamma link, the areas of concentration of DM (which don't even jive with observation), all of it. DM theory is not a "simpler" explanation for gamma rays than suns and planets. It's not supported by any observation in a controlled experiment. There is not one single instance of "dark matter" emitting gamma rays inside out solar system, so what in the world would lead me to believe it occurs "out there somewhere else"?

I'm afraid the DM source of gamma ray theory doesn't survive the first Occum's razor argument. In fact it falls apart over the simplicity factor alone. It lacks empirical support of any kind, and it's not even viable compared to the simpler and *demonstrated* sources of gamma rays.
 
As I have explained in the past, due to the lensing data I've seen, the concept of "unidentified mass" or 'missing mass' is more appealing to me than say MOND theory.

IMO that simply demonstrates we grossly underestimate the amount of mass in a galaxy.
The lensing data explicitly removes the possibility that the missing mass (or rather excess mass) is in the the form of massive objects.

Those links I cited for DRD demonstrate the recent discoveries suggest we have grossly underestimated the amount of dust in the universe as well as the number of smaller stars in a galaxy. Have these more recent discoveries even had a chance to be factored into our galaxy mass estimates?
Can you show they're even in the right ballpark to make a significant difference?

The term "dark matter' as I was taught it in school was mostly though to be standard matter our technologies could not yet identify, more along the lines of MACHO orientation of 'dark matter".
Which has now been ruled out by the lensing data. Hence the transition to WIMP type objects.

Today's new and improved brand is being created in an "ad hoc" manner and being assigned various "properties" that have never been demonstrated.
Not in the slightest. For example the MSSM assigns properties (or rather a range of possibilities for the properties (mass etc)) to particles based on what we already know from the Standard Model and experiment with the added assumption of supersymmetry - something we have independent reasons for believing in. This is anything but ad hoc. In fact the properties of SUSY particles would be the same whether we'd observed DM or not.

The term "dark matter" has changed from being associated with standard material, to being mostly associated with hypothetical SUSY theory with hypothetical and metaphysical properties galore.
They don't really have any hypothetical features not observed in other particles. At least none that I can think of. And I dunno where you get the idea they are "metaphysical" properties from.

When we look at the Fermi images, the material doesn't seem to be concentrated in any one place around the galaxy, instead the entire galaxy seems to glow as though every star and every planet is emitting these wavelengths. That's confirmed too by the fact we can observe the sun traversing the Fermi data set quite clearly. It should hardly be surprising then that we see gamma rays from stars in a galaxy and even planets are known to emit gamma rays inside our own solar system.
I don't see your point.

There's absolutely no need for 'dark matter' to explain 'gamma rays' from a galaxy. There's no empirical link established between 'dark matter" and "gamma rays".
The give us a quantitative alternative.

The whole thing is "assumed", the material itself, the gamma link, the areas of concentration of DM (which don't even jive with observation), all of it.
Wrong. See above.

DM theory is not a "simpler" explanation for gamma rays than suns and planets. It's not supported by any observation in a controlled experiment.
Define "controlled experiment".

There is not one single instance of "dark matter" emitting gamma rays inside out solar system, so what in the world would lead me to believe it occurs "out there somewhere else"?
There's not a single instance of a supernova event inside our solar sytem, so what in the world would lead me to believe it occurs "out there somewhere else"?

I'm afraid the DM source of gamma ray theory doesn't survive the first Occum's razor argument. In fact it falls apart over the simplicity factor alone. It lacks empirical support of any kind, and it's not even viable compared to the simpler and *demonstrated* sources of gamma rays.
You really don't get the idea of quantitative[\B] analysis do you?
 
So tell me, MM, what was the proper - i.e. kosher according to the MM worldview of science - thing to have done wrt the original dark matter (i.e. Neptune)?

You mean "unidentified mass"? When did anyone claim that this particular missing mass was able to pass through walls in a single bound? Emit gamma rays on a whim? When did anyone claim it could puke out positrons anywhere and everywhere? I'm afraid you only serve to demonstrate the obvious here. There's a lot we cannot observe directly and there is every reason to believe that we grossly blew the mass estimates as it relates to the "normal" amount of material in a galaxy. There is at least twice the "dust" we expected to find and four times as many small stars in a galaxy than we realized. You haven't even had time to factor in these changes to our understanding of a makeup of a galaxy, but you still expect me to believe you have everything so figured out that you can estimate the amount of exotic new material in distant galaxy. Come on. Your story isn't even believable. Like Neptune, I'm sure your "missing mass" is made of ordinary matter and baryonic materials.

And would you have railed vociferously against all those who sought to test GR (the solution to the second lot of solar system dark matter, a.k.a. the anomalous advance of the perihelion of Mercury), because it had not been demonstrated in any earthly labs?

No because "gravity" shows up on Earth and does its thing right here on Earth. I'm sure that gravity exists "out there" in space too. Compare and contrast that with hypothetical brands of SUSY particles with hypothetical properties galore that are entirely based on faith, starting with the claim of "longevity".

Have the "professionals" in your industry even revised their mass estimates of normal material in a galaxy based on these new findings? Yes or no? If so, which paper would you cite for us? Has the Fermi team cited these new numbers in any single paper to date?
 
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The lensing data explicitly removes the possibility that the missing mass (or rather excess mass) is in the the form of massive objects.

How do you figure that? It certainly doesn't remove the possibility that ISM and IGM is "dustier" than we thought.

http://www.space.com/scienceastronomy/080515-galactic-dust.html

If it's "twice as bright" as we realized, why wouldn't that equate to a doubling of the number of stars and solar systems in a galaxy?

Even more damaging IMO:
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Given these facts, how can you expect me to believe that we already know how much ordinary matter exists in a distant galaxy?
 
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How do you figure that?
The weak gravitational lensing data shows that the mass cannot be largely in the form of large objects.

It certainly doesn't remove the possibility that ISM and IGM is "dustier" than we thought.

http://www.space.com/scienceastronomy/080515-galactic-dust.html

If it's "twice as bright" as we realized, why wouldn't that equate to a doubling of the number of stars and solar systems in a galaxy?

Even more damaging IMO:
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Given these facts, how can you expect me to believe that we already know how much ordinary matter exists in a distant galaxy?

You do know we not only know how much dark matter there is but what shape it takes right?
 
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[...]

There's a lot we cannot observe directly and there is every reason to believe that we grossly blew the mass estimates as it relates to the "normal" amount of material in a galaxy. There is at least twice the "dust" we expected to find and four times as many small stars in a galaxy than we realized.
Evidence?

Start with our own, the MW galaxy, and then either of the Magellanic Clouds, followed by any other MW satellite galaxy, followed by M31 and/or M33.

[...]

Like Neptune, I'm sure your "missing mass" is made of ordinary matter and baryonic materials.
I have no doubt whatsoever that you are, indeed, sure of this.

However, it has never been the case that the answer to a scientific question like this can be answered by asking MM what he is sure about ...

Perhaps you can put fingers to keyboard, and write a paper actually demonstrating this? And backing it up with quantitative analyses, unbiased sets of references, etc?

If you can't, what do you have, other than a personal, subjective opinion?

And would you have railed vociferously against all those who sought to test GR (the solution to the second lot of solar system dark matter, a.k.a. the anomalous advance of the perihelion of Mercury), because it had not been demonstrated in any earthly labs?
No because "gravity" shows up on Earth and does its thing right here on Earth.
Are you so grotesquely ignorant of the relevant history?

The original "dark matter" (Neptune) worked out just fine, in terms of the then prevailing theory of gravity (Newton's).

Starting around the middle of the 19th century, just the same sort of solution was sought to some new "dark matter" (i.e. the anomalous advance of the perihelion of Mercury) ... and it was even given a name (Vulcan).

Einstein's new theory of gravity did away with the need for a "dark matter" solution, but at the expense of a "dark energy" one (i.e. a theory which could not - then - be empirically tested in any lab on Earth).

An MM clone at the time (1918, say) would have railed most vociferously against this "dark energy" (i.e. an unsubstantiated theory of gravity), and insisted that astronomers lift their game in terms of searching for Vulcan.

And it was not until some four decades later - well after many of the leading astronomers of the day were dead, or had ceased any astronomical research - that GR was tested in a lab here on Earth.

Had MM been the ultimate authority on physics, at the time, no one would even have tried to test GR!

I'm sure that gravity exists "out there" in space too.
Indeed.

The only thing - wrt gravity - that you're not sure about is whether a cosmological constant is required to adequately describe it ...

... well, you also are not sure of the validity of gravitational lensing, of the ISW, of the nature of the EFE, of ...

Compare and contrast that with hypothetical brands of SUSY particles with hypothetical properties galore that are entirely based on faith, starting with the claim of "longevity".
Just like the hypothetical Neptune (as it subsequently became known) and Vulcan (which remains entirely hypothetical)?

Oh, and the "faith" basis is the same as the "faith" basis for GR, the Standard Model (of particle physics), ...

Have the "professionals" in your industry even revised their mass estimates of normal material in a galaxy based on these new findings?
I was not aware that any of these "new findings" referred to our own galaxy (the Milky Way) - can you point me to where, exactly, this reference is to be found?

Yes or no? If so, which paper would you cite for us? Has the Fermi team cited these new numbers in any single paper to date?
Why should they need to, if they have no relevance?
 
The term "dark matter' as I was taught it in school was mostly though to be standard matter our technologies could not yet identify, more along the lines of MACHO orientation of 'dark matter". Today's new and improved brand is being created in an "ad hoc" manner and being assigned various "properties" that have never been demonstrated. The term "dark matter" has changed from being associated with standard material, to being mostly associated with hypothetical SUSY theory with hypothetical and metaphysical properties galore.
I think I see your problem - you are stuck with the science that was taught to you in school many years ago. You have forgotten to learn, especially about the new discoveries that changed this original concept for dark matter.

Dark matter was considered to be "missing matter" from 1933 when Zwicky found that there as not enough matter measured in galactic clusters to explain the orbital motion of galaxies. This is the concept that was taught in schools for the next 40 years.

Then in 1975, came Rubin's observation that the velocity dispersions of galaxies also needed dark matter. This could also be "missing matter" but 40 years of improving observational techniques made this doubtful. Further advances in observation techniques since then finally broke the association of dark matter with "missing matter". The biggest observational straw was that fact that the leading candidate for this (MACHO's) have been detected but not at a level high enough to explain dark matter.

The real observations that showed that dark matter could not be normal matter (i.e. "missing matter") are the colliding galactic clusters of Bullet Cluster and MACS J0025.4-1222 (and even Abell 520).
Here is the situation in the observations in a simplified form:
  1. A is a big blob of gas.
  2. B is a bib blob of gas.
  3. Blob A hits blob A.
    • If the gas is all the same stuff then the result will be another blob of gas.
      It is probable that some of the gas will not not collide. In that case there will be blobs of gas to each side. The size of these outlying blobs will reflect the amount of gas that did not collide.
    • If the gas is a mixture of two kinds of gas , one of which interacts weakly with the other, then the result will be 3 blobs since the weakly interacting gas passes through the other gas.
      The size of these outlying blobs will reflect the amount of gas that did not collide plus the amount of weakly interacting gas.
  4. We see 3 blobs.
    The outlying blobs contain most of the matter.
  5. Thus the gas is made of two kinds of gas, one of which interacts weakly with the other.
You may want to read Starts With a Bang's clear description of Dark Matter in his blog entries.
He also mentions the fact that astronomers measure the mass distribution of galactic clusters and see that the majority of matter is not visible. Have a look at The Camera that Changed the Universe: Part 4
What can you learn from this? Well, other than all sorts of things about the lensed galaxies, you can learn about dark matter! You see, gravitational lensing only cares about mass, and so we can figure out where -- in a cluster like this -- the mass is distributed. The results are breathtaking.
mass_recon0024_500.jpg

What this shows you is that yes, there are spikes where the individual galaxies are. But the cluster is dominated by this giant spherically-distributed mass that's present everywhere, both where there are galaxies and where there aren't. And that has got to be dark matter.
 
There's a very close analogy to the topic of this thread, one that demonstrates the absurdity of MM's position (and the danger it would pose to progress were anyone else to subscribe to it). The analogy is the solar neutrino problem.

Must as Fermi (and other experiments) have detected an unexplained excess of positrons and photons produced by electron-positron annihilation, neutrino detectors starting in the 60's found a strange deficit in the flux of solar neutrinos (specifically, they detected about 1/2 the number expected based on the standard solar model).

Then as now, there were a few possibilities:

1) the experimental results were wrong

2) the standard solar model was wrong, and once that mistake was corrected the measured flux would agree with theory

3) something really new was responsible

Possibility 1) was largely eliminated by more experiments (which found consistent results). Possibility 2) was looked at very closely over many years, but no one could find a problem in the solar model that explained the deficit.

At the same time theorists proposed a far more radical idea fitting into 3): that neutrinos have mass, and moreover that their mass eigenstates do not line up with their flavor eigenstates, which means one type of neutrino can spontaneously turn into another type (thereby avoiding detection in some types of detectors and reducing the measured flux).

Of course that radical theory is now know for certain to be correct. In this case the final confirmation was provided by "lab" experiments (you produce neutrinos at a nuclear reactor, beam them a long distance at an angle that takes them through the crust of the earth, detect them far away when they emerge, and note that some have oscillated into others). If these theories of dark matter being responsible for the excess gamma rays and positrons are correct, it's possible that they will eventually be established in accelerators. But that possibility is irrelevant to whether or not the theories are correct now - they either are or are not, whether or not we can tell. MM's insane criteria - which is that we should not look for anything that hasn't already been found - would preclude any such search, and so we would never know. In the case of solar neutrinos, since there was no evidence (apart from the observed deficit) that neutrinos had mass, MM's criterion would have prevented any experiment from being built to test it, or for that matter any theorists to come up with the idea in the first place. All of that is literally antithetical to science.

I think a good term for the position MM advocates: "antiscience".
 
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There's a very close analogy to the topic of this thread, one that demonstrates the absurdity of MM's position (and the danger it would pose to progress were anyone else to subscribe to it). The analogy is the solar neutrino problem.

Sadly the analogy doesn't work on anyone "sceptical" of neutrino oscillations.
 
Sadly the analogy doesn't work on anyone "sceptical" of neutrino oscillations.

Neutrino oscillations have been confirmed in lab experiments.

But anyway, I'm not trying to convince MM - that's useless. I'm assuming other people might read this thread, and neutrino oscillations are a very good example of the kind of fundamental particle physics that can be learned from astrophysical observations. The correction to the standard model of particle physics that resulted from that was the first one in something like 30 years.
 
[...]

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Have these more recent discoveries even been factored into current galaxy estimates in terms of the number of stars there are in a given galaxy, including our own? How many gamma ray emitting planets shall we assume for every star in your opinion?

[...]
Can you please confirm that The energy output of the Universe from 0.1 micron to 1000 micron and Evidence for a Non-Uniform Initial Mass Function in the Local Universe are the papers you are referring to?
 
Neutrino oscillations have been confirmed in lab experiments.

That's exactly why your analogy (and DRD's analogy fail).

Unlike the hypothetical "dark matter" particle you're claiming is responsible for gamma rays in space, neutrinos have a known source. They show up in labs. We can create "transmitters' and "detectors" and real equipment to measure them. We can see how they interact with matter.

Where does your mythical dark matter particle thingy come come? Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim? For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond? How can I verify it emits gamma rays in an empirical test?
 
That's exactly why your analogy (and DRD's analogy fail).

Unlike the hypothetical "dark matter" particle you're claiming is responsible for gamma rays in space, neutrinos have a known source. They show up in labs. We can create "transmitters' and "detectors" and real equipment to measure them. We can see how they interact with matter.

Where does your mythical dark matter particle thingy come come? Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim? For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond? How can I verify it emits gamma rays in an empirical test?
You keep missing the point, and denying history.

Helium was detected "in the lab" after it was discovered in the Sun.

Nebulium (the hypothesised source of the 500.7 nm (etc) emission lines) was determined to be not a new element well after it was first observed (and [OIII] lines have never been observed "in the lab").

Neutrino oscillations were observed "in the lab" after they were confirmed as a consistent explanation of the solar neutrino problem.

The inverse square nature of (Newtonian) gravitation was confirmed "in the lab" well after the theory was first published.

GR was not tested "in the lab" until well after it was confirmed as a consistent explanation for several sets of astronomical observations.

The neutrino was not observed "in the lab" until after it was confirmed as a consistent explanation for several sets of experimental results.

And so on.

Yet, according to the MM worldview, none of the explanations were legitimate at the time they were first proposed; furthermore, according to this worldview, no "in the lab" tests should ever have been conducted, because there were - at the time, and still today - qualitative explanations that an MM clone could plausibly claim might account for the relevant observations. In this MM worldview, the failure of any such alternative explanation to come even close to being able to account for all relevant results - quantitatively - is utterly irrelevant.

To quote from si's recent post: "I think a good term for the position MM advocates: "antiscience"."
 
That's exactly why your analogy (and DRD's analogy fail).

Unlike the hypothetical "dark matter" particle you're claiming is responsible for gamma rays in space, neutrinos have a known source.

As DRD points out, your own analogy demolishes your position. Neutrinos were posited to explain yet another mysterious deficit (missing energy and momentum in certain radioactive decays, in that case). There was zero direct evidence for their existence, they had never been detected, and their properties were hypothetical and almost completely unknown. By your logic, they should never have been proposed, never investigated, they weren't science.

Where does your mythical dark matter particle thingy come come? Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim?

Every single one of those objections applied to neutrinos when they were first proposed.

For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond?

Because if it did, it wouldn't be dark matter. One of the things we know about dark matter is that it's very stable (has a long lifetime), otherwise it would have decayed.

How can I verify it emits gamma rays in an empirical test?

For now, by looking in the right places. Eventually, perhaps by creating it in an accelerator.
 
Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim? For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond? How can I verify it emits gamma rays in an empirical test?
You are really out of date with your scientific knowlege. You seem to be stuck in your school boy days (some sort of second childhood?)
  • You can get dark matter anywhere you like (just like neutrinos). They are all around you.
  • You can detect them just like you can detect them neutrinos. Build a detector sensitive enough to detect them.
  • Dark matter may do stuff to things here on Earth (see the DAMA/NaI, DAMA/LIBRA experiments).
  • If dark matter emits gamma rays then it emits it here too. The problem is detecting it, e.g. separating it from the much bigger source of gamma rays from natural radition (including the Sun). That is scientists are looking at the much larger density of dark matter at the center of the galaxy.
  • To build a transmitter, firstly build a machine that duplicates the energies of the early universe to produce dark matter particles. Then build a device to channel the dark matter into a beam (black holes may be needed).
 
As DRD points out, your own analogy demolishes your position.

No, your own two analogies demolish your position, not mine. Whereas neutrinos and gravity show up in lab, your mythical "dark matter" dohickies do not.

Neutrinos were posited to explain yet another mysterious deficit (missing energy and momentum in certain radioactive decays, in that case).

Ya, *CONTROLLED* experiments demonstrated that A) either a law of physics was being violated, or B) there was in fact a new particle required to explain that loss of energy. Notice that not a single "controlled" experiment ever required a SUSY particle to explain it and no laws of physics are violated by an absence of SUSY particles. Already your neutrino analogy shows the weakness of your own argument, and DRD's argument too. Both gravity and neutrinos have a known source and we can replicate them in a lab. You can't even be sure SUSY particles exist, let alone replicate any of the properties you keep assigning to them.

There was zero direct evidence for their existence, they had never been detected, and their properties were hypothetical and almost completely unknown. By your logic, they should never have been proposed, never investigated, they weren't science.

Boloney. Empirical controlled experiments made it clear that either a law of physics was violated (highly unlikely) or a new particle was in order (more likely). There as a *SOURCE* identified and a METHOD of observing their direct influences on controlled experiments. You can't identify a source of SUSY particles. You don't even know if they exist at all!

Gravity isn't shy around the lab so DRD's analogy is also meaningless. You're both comparing metaphysical apples to empirical oranges.

Because if it did, it wouldn't be dark matter. One of the things we know about dark matter is that it's very stable (has a long lifetime), otherwise it would have decayed.

Correction: One of the things you *NEED* from you ad hoc gap filler is longevity because without it, your theory is toast. You therefore "made up" a "necessary property" for your mythical gap filler, in this case longevity. It was a property you created based on *NEED* not upon "observation" in a lab.

For now, by looking in the right places. Eventually, perhaps by creating it in an accelerator.

Even if we do ever find a SUSY particle in a collider experiment, how do you know it's going to last even a full millisecond before reverting into something we already know about? Pure faith? Ad hoc need? What?
 
You keep missing the point, and denying history.

No, that's your game, not mine. You're mixing and matching things at will and ignoring the key differences.

Helium was detected "in the lab" after it was discovered in the Sun.

No, a wavelength of light that could not (yet) be identified was observed coming from the sun. Helium was discovered to emit that wavelength in a lab, in controlled conditions. Nothing about the idea was 'untestable' and "unfalsifiable" like your non baryonic DM theory.

Neutrino oscillations were observed "in the lab" after they were confirmed as a consistent explanation of the solar neutrino problem.

Again you're ignoring the implication of having a *CONTROLLED SOURCE* of neutrinos to work with. You can't even tell me where I can get some "dark matter", let alone how I might "detect" it in a controlled experiment. Holy Cow, how can you compare these things when they are clearly very different. In the case of neutrinos we can *create them*. We know where they come from. We can measure them. We can turn on and off a source of "neutrinos'. How might I turn on and off a source of "dark matter"?

The inverse square nature of (Newtonian) gravitation was confirmed "in the lab" well after the theory was first published.

And again with the ridiculous analogies. Gravity is not shy around a lab. DM never shows up in a lab. See the difference?

GR was not tested "in the lab" until well after it was confirmed as a consistent explanation for several sets of astronomical observations.

Yes ,but again "gravity" shows up here on Earth, and therefore I'm sure it occurs "out there" in space too. I have no doubt that gravity exists and has an effect on matter. Compare and contrast that to your mythical matter.

You're clearly missing the key point DRD. Gravity isn't shy around the lab. I'm therefore happy to let you point at the sky and claim "gravity did it" and I'll consider your math formulas to be "useful" in determining how well your mathematical model matches nature's expression of "gravity". Beta decays (and neutrinos) show up in a lab too and therefore they can be measured. They can be isolated in controlled experiments and mathematical models can be compared to actually results of empirical experiments. In no way can your "dark matter" be measured in an empirical experiment because you don't even know if it exists, you don't know where it comes from, you can't turn it on or off, you can't produce of gram of it for experimentation, and you're clueless as to whether it actually has any of the properties you *imagine* it has. In fact all of the "properties" that you "imagine" that it has are all related to what you "need" to prop up your otherwise dead theory. That's sounds more than a little fishy to a real skeptic.
 
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I think I see your problem - you are stuck with the science that was taught to you in school many years ago. You have forgotten to learn,

Er, considering what I've been through for the past 6 years, I'm certain that is not the case.

especially about the new discoveries that changed this original concept for dark matter.

The "original concepts" of "dark matter" centered around and understanding of the limits of our current technologies and a certain amount of "humility" as it relates to our knowledge of space and distant galaxies. There we're no particular "properties" being assigned to "dark matter", other than an acknowledgment that we couldn't see it, presumably due to the limits of our technology.

Today's "new and improved" brand of metaphysical dark matter has all sorts of "superproperties". It's no longer "dark" because of a limit of our technology, it's "dark" because it does not interact with the EM spectrum. It's like superman only better. It can pass through walls. It can emit gamma rays with a single thought. It does what no other type of matter can do, and makes up the majority of the universe according to you guys/gals. We evidently "know" all this because our technology is presumably no longer limited, we have everything all figured out in terms of number of stars in a galaxy, amount of dust in the universe, the "superiority" of our infallible mass estimates of galaxies, etc.

That's all just hogwash. Our technologies are still very limited. We can't see individual stars in distant galaxies we "estimate" them based on a whole series of "assumptions", assumptions that are evidently pretty useless at actually guestimating the amount of mass in a galaxy. Instead of just noting that our mass estimation techniques are critically flawed, we now just *assume we're right* and we "make up" properties in a purely ad hoc manner and make up excuses about how "dark matter" did it.

Dark matter was considered to be "missing matter" from 1933 when Zwicky found that there as not enough matter measured in galactic clusters to explain the orbital motion of galaxies. This is the concept that was taught in schools for the next 40 years.

It was an "honest" explanation of the fact that our technologies were still quite primitive and our understanding of the universe was (is still) very limited.

Then in 1975, came Rubin's observation that the velocity dispersions of galaxies also needed dark matter. This could also be "missing matter"

Indeed. All it did is confirm that we blew our mass estimates of a galaxy and there *must* be more mass we can't account for in a galaxy. None of the *necessitates* a "new form" of mass. Any old mass will do.

but 40 years of improving observational techniques made this doubtful.

How so? What did you suddenly gain "perfect" technology that allowed you to count actual stars in distant galaxies that are millions if not billions of light years away?

Further advances in observation techniques since then finally broke the association of dark matter with "missing matter".

The only thing that "broke" is that your industry "broke" with empirical physics. It started 'winging it" and "making it up" as it went. No longer was it necessary to "demonstrate" any given "property" we might assign "missing matter". Now we can just "make it up" and never have to demonstrate any of it empirically. We now get to point at the sky and claim "God matter did it".

The biggest observational straw was that fact that the leading candidate for this (MACHO's) have been detected but not at a level high enough to explain dark matter.

You're still ignoring the fact that "missing mass" isn't our disagreement. Our disagreement has do to with you *assuming* all sorts of "supernatural" properties about the nature of this "unidentified mass". It's like you see something flying around in the sky that you personally can't identify so you immediately *ASSUME* that it's from a whole different planet!

The real observations that showed that dark matter could not be normal matter (i.e. "missing matter") are the colliding galactic clusters of Bullet Cluster and MACS J0025.4-1222 (and even Abell 520).

Explain *EXACTLY* (and I mean exactly) how any of that stuff demonstrates that it cannot be ordinary matter that our technologies simply cannot account for?

Here is the situation in the observations in a simplified form:
  1. A is a big blob of gas.
  2. B is a bib blob of gas.
  3. Blob A hits blob A.


  1. Your analogy is pitifully oversimplified. Galaxies are composed of solar systems that are separated by light years. The odds of any of them actually slamming into one another during a "galaxy collision" are astronomically low. It's far more probable that much of the gas in the ISM would 'interact" and have some effect on the movement of the dust in the other galaxy's ISM, but the majority of the matter in a given solar system is going to go right on through the "collision" process relatively unscathed. All that data demonstrates is that most of your "missing mass" is evidently located in the stars and solar systems and point like masses rather than the dust particles in the ISM.

    He also mentions the fact that astronomers measure the mass distribution of galactic clusters and see that the majority of matter is not visible.

    Ya, so? Is that a limit of our technology perhaps, or do you really believe that we have the capability of "seeing" everything there is to see in a distant galaxy that is millions or billions of light years away?
 
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Evidence?

From the article and paper I cited earlier:

Astronomers have known about interstellar dust for a while, but they haven't been able to quantify just how much light it blocks. Now a team of researchers has studied a catalogue of galaxies and found that dust shields roughly 50 percent of their light.

"I was shocked by the sheer scale of the effect," said Simon Driver, an astronomer from the University of St. Andrews in Scotland who led the study. "Most people just kind of said, 'We suspect dust is a minor problem.' I spent much of my career working on deep images from Hubble and I've always ignored dust almost entirely."

The result will likely cause many astronomers to revise their calculations of the intrinsic brightness of many celestial objects, Driver said. Until now, many astronomers thought stars and galaxies were really about 10 percent brighter in optical light than they appeared because of dust. If the new findings are true, it turns out that objects in the sky are about twice as bright than they appear.

"This is a strong, clear-cut result," Driver told SPACE.com. "We've really got to take dust seriously and we've got to make large adjustments to our magnitude calculations." (A magnitude scale is used to define brightness of celestial objects.)

Why should they need to, if they have no relevance?

So you're telling me that it is absolutely irrelevant that we've been underestimating the amount of brightness by such a significant percentage? It has *NO* affect whatsoever on our mass estimation of a galaxy?
 
No, your own two analogies demolish your position, not mine. Whereas neutrinos and gravity show up in lab, your mythical "dark matter" dohickies do not.
But they didn't at the time they were proposed. What is it that you don't understand about this really really basic argument?

Ya, *CONTROLLED* experiments demonstrated that A) either a law of physics was being violated, or B) there was in fact a new particle required to explain that loss of energy.
Controlled experiments demonstrate the need for matter that only interacts weakly. This could be SUSY particles. On the other hand, it may not be.

Notice that not a single "controlled" experiment ever required a SUSY particle to explain it
That probably depends on whether you think we should be looking for GUTs. There's also the small matter of the hierarchy problem which you might like to stick in your favourite search engine.


and no laws of physics are violated by an absence of SUSY particles. Already your neutrino analogy shows the weakness of your own argument, and DRD's argument too. Both gravity and neutrinos have a known source and we can replicate them in a lab. You can't even be sure SUSY particles exist, let alone replicate any of the properties you keep assigning to them.

Boloney. Empirical controlled experiments made it clear that either a law of physics was violated (highly unlikely) or a new particle was in order (more likely).
Exactly the same with dark matter. Either our law of gravity is being violated or a new particle is required. You're not helping your argument here.

There as a *SOURCE* identified and a METHOD of observing their direct influences on controlled experiments. You can't identify a source of SUSY particles. You don't even know if they exist at all!
Uh-huh. You really don't this science malarkey do you. You're arguing against the existence of something because we don't know that it exists for definite. If we always did this we'd have no science at all.

Gravity isn't shy around the lab so DRD's analogy is also meaningless.
The properties of gravity that were noticed by Newton at the time, like the -2 dependance were completely impossible to measure at the time in a lab. It took centuries for this to be rectified.

You're both comparing metaphysical apples to empirical oranges.
Its not metaphysics at all.

Correction: One of the things you *NEED* from you ad hoc gap filler is longevity because without it, your theory is toast. You therefore "made up" a "necessary property" for your mythical gap filler, in this case longevity.
Nope completely wrong. The lightest particle in the Minimal Supersymmetric Standard Model (for instance) is stable. That is, the simplest possible extension that we can make to the Standard Model to include supersymmetry gives a stable supersymmetric partner. This is in no way made up. Its a consequence that is dependent only on our knowledge of the SM, QM and the assumption that the Universe is supersymmetric.

It was a property you created based on *NEED* not upon "observation" in a lab.
Nope. Completely wrong. Why do you continue to argue against something you have no idea about in such an agressive manner?

Even if we do ever find a SUSY particle in a collider experiment, how do you know it's going to last even a full millisecond before reverting into something we already know about? Pure faith? Ad hoc need? What?
None of these, R-parity conservation.
 
So you're telling me that it is absolutely irrelevant that we've been underestimating the amount of brightness by such a significant percentage? It has *NO* affect whatsoever on our mass estimation of a galaxy?
It does have an effect - the intrinsic brightness of many celestial objects may have been underestimated. That is what the paper states.

IMO (as a non-astronomer) I would say that this has *NO* effect whatsoever on our mass estimation of a galaxy. If it did then the authors would have stated this since it is quite an important bit of astronomy.


But the mass estimation of galaxies is only one part of the detection of dark matter. Most of the normal matter in the universe turns out to be intergalactic medium, i.e. plasma.

You may want to read Starts With a Bang's clear description of dark matter in his blog entries.
Although there are other ways to measure mass gravitationally, these are the main ones. They all give the same answer, too: about 25% to 30% of the total energy in the Universe is some form of gravitational mass. But what of the stars? It turns out that stars are only about 0.5% of the mass in the Universe.
Even if this article turns out to be correct and intrinsic brightness is used to calculate the mass of galaxies (I have my doubts about this) then stars become about 1% of the mass in the Universe. Dark matter then makes up the remaining 24% to 29% of gravitational mass.
 
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So you're telling me that it is absolutely irrelevant that we've been underestimating the amount of brightness by such a significant percentage? It has *NO* affect whatsoever on our mass estimation of a galaxy?

Well for a start, for stars of ~ 1 solar mass the mass luminosity relationship gives:

L/Lsun = (M/Msun)4
Or
M/Msun= (L/Lsun)0.25
So even if we were underestimating the luminosity of a star by a factor of 2, we'd underestimating the mass of the star by a factor of just 1.2. So no, it doesn't make a great deal of difference.
 
Even more damaging IMO:
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Given these facts news articles, how can you expect me to believe that we already know how much ordinary matter exists in a distant galaxy?
Fixed your post.

I already found the paper for the article in a previous thread where you brought up this point
Evidence for a Nonuniform InitialMassFunction in the Local Universe.

DeiRenDopa has addressed this in some posts starting with:
By comparing the paper to the PR, it is easy to see why one should always go to the primary source, especially when trying to draw inferences that are beyond what is stated.

I'll write more about this in later posts, but the techniques used to estimate total mass in galaxies are many and varied, and they give consistent answers (albeit sometimes the uncertainties are big).

Wrt this particular paper, a possible implication concerning the estimated total baryonic mass in a galaxy is: if you use a combo of estimated SFR and IMF to derive a (baryonic) mass estimate, you may have introduced a systematic error; specifically, the IMF for LSBs (low surface brightness) galaxies may be significantly different from the IMF for other galaxies (and even this is too extreme; the paper reports only estimates of the top part of the IMF, specifically O and B stars).

We do not know how much ordinary matter exists in a distant galaxy to the nearest gram. We do have estimates of the masses of galaxies. The uncertainties in these are large. No one would be surprised if a particular technique was a factor of 2 either too big or too small.
But multiple techniques are used and they agree! No one would be as silly as to think that the masses of galaxies were a factor of 40 too small.
 
MM,

It’s the 1930’s and guys and gals studying nuclear properties noticed that when a neutron disintegrates into a proton and electron something is wrong. The observed momentums don’t all cancel out. Meaning either conservation of energy, momentum and angular momentum is wrong , or, wait for it … something not directly observed is also part of the picture. I’m sure you know this by now, but along comes a smart guy named Pauli and he postulates that a “little neutral one” or neutrino is the missing piece of the picture above. From the Neutron disintegration reaction, or Beta decay, a great number of the properties of the neutrino can be deduced. The neutrino is subsequently accepted by the nuclear physics community as a fundamental particle and is used in the story of a whole host of other phenomena.

Now here is the crux of the story … All of this was done well BEFORE the neutrino was directly observed.

How is this ANY DIFFERENT from the situation now? And don’t give us the line that neutrinos have been observed in the lab and so forth. BEFORE they we observed, they were postulated to exist and used by scientists to explain observations and measurements.

I challenge you to explain how the current situation with Dark Matter is fundamentally different that the history of the neutrino. How is the hypothesis of Dark Matter not science?
 
Now here is the crux of the story … All of this was done well BEFORE the neutrino was directly observed.

How is this ANY DIFFERENT from the situation now?

The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process. The other particles in the decay process were directly measured in the experiment and the amount of left over energy could *only* (no other possible option existed) be caused by a new particle, or a failure in a "law" of physics. No other particle we had identified could account for that specific amount of energy.

That "unidentified mass" in a distant galaxy could be caused by anything. There was never a "controlled experiment" performed that directly measured the actual normal mass in those galaxies. We simply "estimated" the amount of normal mass in a galaxy based on a whole range of assumptions. That distant missing mass doesn't *REQUIRE* a new form of matter to exist. No laws of physics "require" that we postulate a new and exotic form of matter. Nothing absolutely necessitates that we postulate an exotic new form of matter. Our mass estimates are simply wrong for all we know because our technologies are still very limited. We can't actually "count" the number of stars in a galaxy we "estimate" them based on lots and lots of lots of questionable assumptions.

Whereas neutrinos were discovered (and first postulated) via empirical physics in the lab, SUSY particles have not. Whereas neutrinos were *necessary* to keep laws of physics from being violated, SUSY theory is not. Whereas neutrinos have a known source, SUSY particles do not. There's no comparison because we have not and never could perform a "controlled experiment" to weigh the amount of normal matter in a galaxy. That's the key difference.
 
Well for a start, for stars of ~ 1 solar mass the mass luminosity relationship gives:

L/Lsun = (M/Msun)4
Or
M/Msun= (L/Lsun)0.25
So even if we were underestimating the luminosity of a star by a factor of 2, we'd underestimating the mass of the star by a factor of just 1.2. So no, it doesn't make a great deal of difference.

So, just out of curiosity, why did you subjectively decide to assume that there were the same number of point sources (just larger) rather than simply doubling the number of point sources?
 
It does have an effect - the intrinsic brightness of many celestial objects may have been underestimated. That is what the paper states.

IMO (as a non-astronomer) I would say that this has *NO* effect whatsoever on our mass estimation of a galaxy.

Baloney! That is physically impossible. Somehow you're going to have to add mass to account for that additional brightness. As TBT notes, even in the most conservative way of "adjusting' the numbers, some adjustment will absolutely be required.

But the mass estimation of galaxies is only one part of the detection of dark matter. Most of the normal matter in the universe turns out to be intergalactic medium, i.e. plasma.

Ya, and evidently it's "twice as dusty" too.

Your whole argument is predicated upon an *accurate* "guestimate" of the amount of "normal" matter in a galaxy, and these recent papers demonstrate that our estimates of normal mass in a galaxy has some
"serious" flaws.
 
[...]
The inverse square nature of (Newtonian) gravitation was confirmed "in the lab" well after the theory was first published.
And again with the ridiculous analogies. Gravity is not shy around a lab. DM never shows up in a lab. See the difference?
I think your (total?) inability to grasp that theories are quantitative means you cannot, and will not, understand this.

What Newton did (among other things) was develop a theory which could account for the observed motions of the Sun, Moon and planets - quantitatively.

Until Newton, no one expected that the heavens would follow rules that are the same as things on the Earth did, and following the MM approach, positing that masses attract each other, according to an inverse square law, is just as much a hypothetical as DM. Today it's easy to link the falling of dense objects, here on the surface of the Earth, with the attraction between two masses (and a force we call 'gravity'); at the time, the idea of 'gravity' (as a shorthand for mutual attraction of masses) was a totally radical idea.

And that's where the testing "in the lab" comes in: this brand new theory of a hypothetical entity called "gravity" was not tested - per MM's worldview - for many decades after the theory was published (indeed, not until well after Newton's death).

GR was not tested "in the lab" until well after it was confirmed as a consistent explanation for several sets of astronomical observations.

Yes ,but again "gravity" shows up here on Earth, and therefore I'm sure it occurs "out there" in space too. I have no doubt that gravity exists and has an effect on matter. Compare and contrast that to your mythical matter.

You're clearly missing the key point DRD. Gravity isn't shy around the lab. I'm therefore happy to let you point at the sky and claim "gravity did it" and I'll consider your math formulas to be "useful" in determining how well your mathematical model matches nature's expression of "gravity". [...]
You realise that you just allowed for a cosmological constant (Λ) explanation for dark energy, don't you? :)

I mean, Λ is part of a math formula for gravity, I can point to the sky and say 'gravity did it', and show that the mathematical model matches nature's expression of gravity very well. :D
 
But they didn't at the time they were proposed. What is it that you don't understand about this really really basic argument?

Please read my response to Dso. It's not just a question of "could we empirically demonstrate it" at the moment they were proposed, it's the fact that no laws of physics are at stake without a SUSY particle, and no empirical experiment requires that a SUSY particle exist.

Controlled experiments demonstrate the need for matter that only interacts weakly.

What specific "control" mechanism are you referring to?
 
The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process.
... snipped non-science stuff,,,.

The *important* similarity is that even the very postulation of dark matter came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured
  • The motion of galaxies in galactic clusters.
  • The motion of stars in galaxies.
  • The distribution of matter in galactic clusters.
  • The distribution of the intergalactic medium in galactic clusters.
Then there are the
  • *EMPIRICAL EXPERIMENTS* that may have indirectly measured dark matter here on Earth.
  • *EMPIRICAL EXPERIMENTS* that are being done now to directly measured dark matter here on Earth.
 
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