Split Thread Michael Mozina's thread on Dark Matter, Inflation and Cosmology

[Reality Check]

The point the reader should note is that RC's list contains things that have all been seen in a lab, with the exception of a black hole.

The point is that the observations of dark matter involves things that have been seen in a lab, i.e. light and gravity.
From this scientists deduce that dark matter exists. This is the same logic that allows them to deduce that stars exist without having a star in the lab.

The fact that dark matter has not yet been detected in a lab does not mean much. The evidence that dark matter is needed in order to make the universe look like what it presents itself to us is the important point. The observations allow scientists to deduce the properties of dark matter. These properties rule out baryonic matter.

 

[Michael Mozina]

And as far as I can tell, well over 90% of the posts go over ground that has been covered before, often many times, on older JREF Forum threads ... with the same outcomes.

Question for DazzaD, Perpetual Student, RC, Tubbythin, and Tim Thompson (did I miss anyone?): in your exchanges with MM in this thread, have you learned anything new, in terms of the case MM seems to be trying to make?

If so, what (I'm really quite interested)?

You even read the last four papers eh? You're such a trip.

 

[Tubbythin]

So we don't even have the technology to see something the size of Earth in our *OWN* galaxy, and you expect me to believe we can account for all the mass in galaxies that are millions of light years if not billions of light years away? Don't you find that the least bit "hard to swallow"?

Earth-sized objects aren't invisible (in the IR). They're just difficult to detect. The fact that we haven't detected any (?) to date is evidence AGAINST such things making up a significant fraction of dark matter. If they made up a significant fraction then we would have detected them by now.

 

[Michael Mozina]

The point is that the observations of dark matter involves things that have been seen in a lab, i.e. light and gravity.

And based on those tools, I'll let you suggest your mass estimates aren't worth the paper they are printed on, and more matter exists out there than you can account for. Those tools don't tell you anything about the nature or makeup of the material, and you can't plug the gaps with invisible friends by "default".

From this scientists deduce that dark matter exists. This is the same logic that allows them to deduce that stars exist without having a star in the lab.

Great, we agree your mass estimates of galaxies are worthless. Now what?

The fact that dark matter has not yet been detected in a lab does not mean much.

What are you talking about. Everything smaller than Earth is 'dark matter' because we can't even see that sized object in our own galaxy. What evidence do you have that "dark matter" is anything other than ordinary matter?

The evidence that dark matter is needed in order to make the universe look like what it presents itself to us is the important point. The observations allow scientists to deduce the properties of dark matter. These properties rule out baryonic matter.

No, they just rule out your galaxy mass estimate model and you refuse to accept it. You therefore stuff the gaps of your ignorance with invisible friends and viola a religion is born.

 

[Michael Mozina]

Earth-sized objects aren't invisible (in the IR).

So they are a form of 'dark matter', is that what you mean?

They're just difficult to detect.

So how do you know how many of them exist in a given galaxy?

The fact that we haven't detected any (?) to date is evidence AGAINST such things making up a significant fraction of dark matter. If they made up a significant fraction then we would have detected them by now.

I don't follow your logic one iota. You could have dozens and dozens of Earth sized planets in any given solar system and we don't have the technology to see even one of them yet. How can you claim to know what "dark matter" is made of if you can't rule out ordinary matter or see all the ordinary matter in *THIS* galaxy yet?

 

[Tubbythin]

And as far as I can tell, well over 90% of the posts go over ground that has been covered before, often many times, on older JREF Forum threads ... with the same outcomes.

Question for DazzaD, Perpetual Student, RC, Tubbythin, and Tim Thompson (did I miss anyone?): in your exchanges with MM in this thread, have you learned anything new, in terms of the case MM seems to be trying to make?

If so, what (I'm really quite interested)?

I've learnt that often the would-be results of the arguments Michael makes are in direct contradiction to the argument he's trying to make.
His case seems to be there can be nothing new in physics which he wasn't taught at school unless you can make a gram of it in a lab. Which is, without doubt, one of the stupidest arguments against the current cosmological paradigm I have ever heard.

 

[Tubbythin]

So they are a form of 'dark matter', is that what you mean?

Depends on your definition of dark matter. They certainly interact electromagnetically.

So how do you know how many of them exist in a given galaxy?

I couldn't give you a precise number. But for them to be the real answer to the dark matter problem we'd need something like 5 times the mass of them as we have stars. Which means we'd need something like 5 million of them for every star! If that were the case the sky in the IR would be much much much much much much brighter than it is.

I don't follow your logic one iota. You could have dozens and dozens of Earth sized planets in any given solar system and we don't have the technology to see even one of them yet. How can you claim to know what "dark matter" is made of if you can't rule out ordinary matter or see all the ordinary matter in *THIS* galaxy yet?

The point is we wouldn't need dozens and dozens. We'd need millions and millions.

 

[Reality Check]

Repulsive component of gravity? Huh? Let's see you jump your way off the planet with that repulsive force you're talking about. What repulsive component of gravity?

Read what I said MM:

Besides the stupidity of you not understanding that negative pressure is standard physics, dark energy is roughly equivalent to a small repulsive component of gravity but the force it exerts does not obey the inverse square law - it varies linearly with distance (increases with distance).

Stanford University has a YouTube series of Professor Leonard Susskind presenting a series of lectures on GR. The second lecture starts with a discussion of dark energy and what it does in everyday situations.


Your answer reveals your ignorance of dark energy.

1. Dark energy is not an actual repulsive component of gravity.
2. Dark energy doesn not have the same force law as gravity.
3. In addition dark energy is really weak and only has measurable effects at scales about the size of the observable universe.

Your definition of "negative pressure" is pointless and meaningless in terms of actual physics because no such thing exists in the physical world.

Where did I define negative pressure?

Negative pressure exists in the real worl, e.g the- Casimir effect.
But you know this since an attempt to explain the Casimir effect is in the
Lambda-CDM theory - Woo or not? thread. This extended over many many posts and was obviously unsuccessful .
Maybe you can answer this post from there now:

First asked 26 March 2009
I know that these are absurdly simple questions that a high school student could answer but that should just make it easier for you .



Here is a simpler situation: Consider these 2 scenarios

1. A force F pushes on a surface that has an area of A.
2. A force F pulls on a surface that has an area of A.

What is the pressure in these 2 scenarios?
​

If you do not know what pressure is or cannot use the standard defeinition of pressure that then have a guess at:

Is the pressure positive or negative in each of the 2 scenerios?
​

First asked 1 April 2009
Now prove your assertion (that the Casimir effect is air pressure) by showing the the air pressure between 2 parallel plates exerts a pressure that varies as the fourth power of the distance betwen the plates (as shown experimentally).
For a genius like you this should be simple. But given your track record with questions I will timestamp this question.

I will add the outstanding questions that other posters have asked:


Asked 2 April 2009 (and many times before)

• What is your definition of pressure (citations please) that only allows pressure to be positive?
• What is the error in the derivation of the pressure of the Casimir effect that leads to the pressure being negative?
• And a bonus question: Why do scientists actually measure a negative pressure?
  (since you have problems with infinity as in your recent posts, replace it by 10¹⁰¹⁰ pascals!)
  Originally Posted by sol invictus [URL="http://www.internationalskeptics.com/forums/helloworld2/buttons/viewpost.gif"]http://www.internationalskeptics.com/forums/helloworld2/buttons/viewpost.gif[/URL]
  Here's a paper measuring Casimir pressure. Note the sign of the result (see e.g. Figure 1), and the functional form (which shows that the pressure tends to minus infinity as the cavity shrinks - which in MM's world means the pressure outside must be +infinity).

As I said in another thread:

People can ignore this comment since it is from someone who thinks that the ideal gas law is a definition of pressure! It is of course the pressure in the specific case of an ideal gas.

The actual definition of pressure lets the value of the pressure be negative. If the force normal to a surface is directed towards the surface then the pressure is treated as positive (e.g. atmospheric pressure). If the force normal to a surface is directed away from the surface then the pressure is treated as negative. The Casimir effect between 2 parallel metallic plates exerts a negative pressure. This is evident from both the theory and the actual experimental measurements of negative pressure.

 

[Reality Check]

And based on those tools, I'll let you suggest your mass estimates aren't worth the paper they are printed on, and more matter exists out there than you can account for. Those tools don't tell you anything about the nature or makeup of the material, and you can't plug the gaps with invisible friends by "default".

And based on those tools (light and gravity) the mass estimates are workth the paper thay are printed on.


For example light tells us (Dark Matter: The evidence from astronomy, astrophysics and cosmology) the density of matter in the universe (no calculation of galactic mass need apply ).

• Analysis of the WMAP data tells us that
  • the total mass density parameter is ~0.26
  • baryonic density parameter is ~0.04. This agrees with the amount of visible matter that astronomers calculate in other techniques.
  • thus the density of dark matter in the universe is ~0.22.
• Baryonic acoustic oscillations (BAO) tell us that
  • the total mass density parameter is ~0.26.
  • the ratio between the baryonic and total density parameters at very large scales is 0.18 +/- 0.04. So the baryonic density parameter is ~0.05 +/- 0.01.

The BAO results mean that astronomers have found about 80% of the baryonic matter in the universe (at least 66% if we use the pessimistic limit of the result).

Great, we agree your mass estimates of galaxies are worthless. Now what?

Great, now we know that you cannot read. There was nothing about mass estimates in that sentence.

What are you talking about. Everything smaller than Earth is 'dark matter' because we can't even see that sized object in our own galaxy. What evidence do you have that "dark matter" is anything other than ordinary matter?

All the evidence that you are ignoring.

No, they just rule out your galaxy mass estimate model and you refuse to accept it. You therefore stuff the gaps of your ignorance with invisible friends and viola a religion is born.

That is idiotic.
The results confirm the "galaxy mass estimate model".

 

[Michael Mozina]

Right. But you never asked about sources of dark matter.

Well, if we expect to have a "control mechanism" we'll need a known source of them, like we had a known/hypothesized source of neutrinos. In the case of neutrinos, the on/off process of the nuclear generator was the "control mechanism" that could be used to confirm our hypothesis. What sort of source of "Dark matter" can you provide?

As I explained previously, and you completely ignored, scientific control mechanisms are not, in general, on off switches.

I'm not asking for anything fancy however, just some way to verify that the 'dark matter" did it, vs. anything else that may have triggered the process in question or in use in the experiment. In the case of the neutrino, we had a theoretical source for them. What's the corresponding source for DE/DM/Inflation?

Control mechanisms are things that help you to measure one thing by reducing, removing or otherwise accounting for other things that could effect the experiment.

Ok, and I would add that it allows us to isolate real "causes" and measure real "effects".

Eg, placing the experiments hundreds of metres under ground is a very clear and obvious control mechanism for reducing (by a large factor) the effect plain old boring cosmic rays can have on your experiment.

Sure, but like the neutrino "experiments" we still need a "source" that can be 'controlled', otherwise it could be "anything else' and we could not demonstrate a cause/effect relationship between our experiments and our theoretic source. Without a controlled source, it's a "argument of the gaps" sort of process, where anything and everything we can't otherwise explained gets stuffed with our pet theory deJour.

 

[Michael Mozina]

Depends on your definition of dark matter. They certainly interact electromagnetically.

Ya, but they are still "dark" to us, even in our OWN GALAXY! This brings us right back to my earlier question of the meaning of 'dark' and whether it's dark because of our limited technology (we can't see every photon) or because it's "invisible".

 

[Michael Mozina]

I've learnt that often the would-be results of the arguments Michael makes are in direct contradiction to the argument he's trying to make.
His case seems to be there can be nothing new in physics which he wasn't taught at school unless you can make a gram of it in a lab. Which is, without doubt, one of the stupidest arguments against the current cosmological paradigm I have ever heard.

It's only "stupid" according to you because you can't empirically demonstrate any of your beliefs. Is that really my personal fault? Did I make you choose a belief system that defies empirical support? If I asked you to demonstrate the existence of gravity here on Earth, you could easily do so. If I asked you to demonstrate 'current flow' here on Earth, you could easily demonstrate that process 'empirically' as well. The only reason you claim it's "stupid" is because your belief system is built on top of metaphysical quicksand and you don't want anyone to notice.

 

[Tubbythin]

Well, if we expect to have a "control mechanism" we'll need a known source of them, like we had a known/hypothesized source of neutrinos. In the case of neutrinos, the on/off process of the nuclear generator was the "control mechanism" that could be used to confirm our hypothesis. What sort of source of "Dark matter" can you provide?

No we don't. It's be useful but is isn't a necessity. The positron was discovered from cosmic rays. There's no one source of cosmic rays and no on off switch. It could still, however, be uniquely identified as being a positron from the shape of the track it made in the cloud chamber.

I'm not asking for anything fancy however, just some way to verify that the 'dark matter" did it, vs. anything else that may have triggered the process in question or in use in the experiment. In the case of the neutrino, we had a theoretical source for them. What's the corresponding source for DE/DM/Inflation?

There's no one source for DM and no need for one.

Ok, and I would add that it allows us to isolate real "causes" and measure real "effects".

I suppose.

Sure, but like the neutrino "experiments" we still need a "source" that can be 'controlled', otherwise it could be "anything else' and we could not demonstrate a cause/effect relationship between our experiments and our theoretic source.

No we don't. We need a signal that is unique to the thing we're looking for. The "controlled" source for the first detection of neutrinos wasn't really all that controlled and was used because it provided enormous neutrino fluxes. Turn the reactor of and you'll still get neutrinos from it. The real genius of that experiment was the unique signature that neutrinos would make in the detector system.

Without a controlled source, it's a "argument of the gaps" sort of process, where anything and everything we can't otherwise explained gets stuffed with our pet theory deJour.

No it isn't. No more so than the discovery of the neutrino was an argument of the gaps.

 

[Tubbythin]

Ya, but they are still "dark" to us, even in our OWN GALAXY! This brings us right back to my earlier question of the meaning of 'dark' and whether it's dark because of our limited technology (we can't see every photon) or because it's "invisible".

They wouldn't be if there was millions of them for every star.

 

[Tubbythin]

It's only "stupid" according to you because you can't empirically demonstrate any of your beliefs. Is that really my personal fault? Did I make you choose a belief system that defies empirical support? If I asked you to demonstrate the existence of gravity here on Earth, you could easily do so. If I asked you to demonstrate 'current flow' here on Earth, you could easily demonstrate that process 'empirically' as well. The only reason you claim it's "stupid" is because your belief system is built on top of metaphysical quicksand and you don't want anyone to notice.

No. Its stupid because things which are difficult to observe are less likely to have been observed so you were less likely to have been taught about them in school. What your denying is the possibility that science may have moved on since then.
Dark matter certainly doesn't defy empirical support. There are countless independent observation showing the same thing.

 

[Reality Check]

Ya, but they are still "dark" to us, even in our OWN GALAXY! This brings us right back to my earlier question of the meaning of 'dark' and whether it's dark because of our limited technology (we can't see every photon) or because it's "invisible".

Actually this brings us back to the "dark matter is rocks" idea that you raised in the Fermi and dark matter thread.
That idea is wrong for several reasons, primarily that rocks at the density and speed of dark matter collide and turn into hot plasma on cosmological or shorter time scales.
You have a number of outstanding questions there which I will repeat here.

The answers to these questions seem to be outstanding, MM:

• Michael Mozina rocks = dark matter idea Question 1:
  Why do astronomers not see that the number of stars increases manyfold as they look back in time?
  Basically where does the "lumpy stuff" (rocks or black holes since it cannot be "dusty plasma" or MACHOs) come from?
• Michael Mozina rocks = dark matter idea Question 2 :
  Why have astronomers not noticed 40 Milky Ways of "lumpy stuff" between us and the Andromeda Galaxy?
• Michael Mozina rocks = dark matter idea Question 3:
  
  Why have astronomers not found your "lumpy stuff"
  • Passing through the Solar System?
  • Floating in interstellar space?
• Michael Mozina rocks = dark matter idea Question 4:
  Why have astronomers not found seen that galaxies become less dense with increasing distance from us?
• Michael Mozina rocks = dark matter idea Question 5:
  Why is the "lumpy stuff" in intracluster space so much of the mass of the cluster when there has been ~13 billion years for the galaxies to vacuum up the "lumpy stuff"?
• What is wrong with the computer simulations of colliding galactic clusters that include dark matter as WIMPs and match the observations?
  The observations include: NASA finds further proof of dark matter(I really dislike that "proof" word - it should be "evidence").

In addition, ben m pointed out in this post the the collision frequency of "lumpy stuff" as rocks means that sub-MACHO size rocks will turn into dust and plasma.

Your reply was to revert to your "dusty plasma" idea as the majority of dark matter. ben m pointed out that the collision rate of dust is measured in years so you are back to easily detectable plasma for the dust.
And then there is the problem of why the plasma part of "dusty plasma" is not interacting electromagnetically.

Another observation that may be pertinent:
Evolving Chemicals is a blog entry about a review paper that plots the "metallicity" (the percent of elements heavier than helium) of the Gamma Ray Bursts (GRB) and Quasars (QSO) against redshift. There is a large amount of scatter in the plot but it is clear that the metallicity has increased (possibly logarithmically).
IMO Your "lumpy stuff" idea means that stars will form with a large metallicity because they will include lots of dark matter rocks. Thus the data should not fit a logarithmic decrease to zero. It should be a decrease on top of a "dark matter rocks" background, i.e. not to zero and maybe not even logarithmic.

 

[W.D.Clinger]

Question for DazzaD, Perpetual Student, RC, Tubbythin, and Tim Thompson (did I miss anyone?): in your exchanges with MM in this thread, have you learned anything new, in terms of the case MM seems to be trying to make?

As a non-participant, I can't answer that.

As a non-physicist lurker, however, I can report that I have learned a number of things by following this thread, and that it has been far more interesting than reading Bjarne's threads. It isn't hard for lurkers to figure out which participants know what they're talking about, and which participant can be ignored.

Will

 

[ben m]

Ya, but they are still "dark" to us, even in our OWN GALAXY! This brings us right back to my earlier question of the meaning of 'dark' and whether it's dark because of our limited technology (we can't see every photon) or because it's "invisible".

Two points.

First: star counting does see "every photon", or enough of them to count stars very accurately. How do I know? Because stars live in the disk of the galaxy. The disk has its own gravity that we can measure using a certain component of stellar velocity distributions. When we count the stars and gas in the disk of the galaxy (The Astrophysical Journal 554 (20 June 2001): 1272–1281 et. seq.), then we measure vertical velocity dispersions to measure the total mass of the disk (Astronomy and Astrophysics 329 (1998): 920–936), we're getting it right. Our technology is able to see everything it needs to see in the disk of the Milky Way. The disk is made out of stars and gas and we are perfectly competent at adding them up.

Meanwhile, the other component of the velocity (radial/tangential) tells us the mass of the Milky Way halo. The halo has 4x the mass of the disk (measured gravitationally) but only a tiny, tiny fraction of the stars and gas. The halo is not something strange and far away; some of it is near Earth and as easy to see as the disk is, like Kapetyn's Star.

In other words: you're imagining a telescope error that explains dark matter observations. You have no evidence of such an error; you continue insisting on it in spite of evidence to the contrary; you can't describe what direction this error would have to have gone in. You're making it up out of thin air without even knowing what you mean and without paying attention to data which might clear it up. You're not even calling it a "hypothesis", you're just assuming that it is the answer by default.

Second: I will help you construct a working baryonic dark matter hypothesis.

Go through the periodic table. That, plus black holes, plus neutron stars, is everything that baryons can possibly do. Baryons can be hydrogen, they can be helium, carbon, lead, etc. They don't have some secret cabal of other, hard-to-see things they can be, do they? Unobtanium? Dilithium?

Now hypothesize: "The Milky way has a halo made of known material X (either a chemical element, or neutron star/black hole material), distributed in N chunks of masses M with probability Y(M), such that the integral (dM) of N M Y(M) is 5x10^11 solar masses." There, I have just written down all possible baryonic dark matter models.

You want a baryons-as-dark-matter model to be true? OK, go ahead. Tell me X and tell me Y(M) for a model that you think might correctly describe gravitational observations of the Milky Way.

OK, got one? Ready? If you can't do it alone, let me give you an example: say that X is "carbon" and Y(M) is "100% probability of being between 0.7 and 0.9 Ceres masses". There, that's a "rocks" dark matter hypothesis just for example. You could say "X is Earthlike composition (O, Si, Fe) and Y(M) is a powerlaw M^-3 extending down to M = 30amu (free neutral atoms) and up to M=10^27 kg (Jupters)". You cannot think of a baryons-as-dark-matter hypothesis which could not be described like this.

Got one? One of mine, or your own? OK. You're not going to like this, but:

a) What you just did was curve fitting. You took some completely unknown parameter space ("We have no direct observations whatsoever of X or of Y(M) since we've never seen these baryons") and hand-picked a subset of it, not because it was super-physically-motivated, but because "any other choice would be ruled out already". Your insistence on "rocks" or "moons" is an informal curve-fit which you are tweaking to avoid a microlensing constraint. You cannot, for example, do a "controlled lab experiment" to show that Y(M) is M^-3. We just pick that number, call it a hypothesis, and evaluate that hypothesis. You know what? That's fine. Don't knock it when scientists do it, even if their hypothesis is different than yours. You can knock their hypothesis if it is ruled out by the data, or made irrelevant by the discovery of something else.

b) If your Y(M) extends to Moon-sized objects it is probably ruled out by microlensing. Sorry, that axes black holes and neutron stars too.

c) If your Y(M) is only in superheavy objects ("loose" SMBHs) then it is ruled out by Galactic disk stability.

d) If your X is anything other than H+He, it is ruled out by the low heavy-metal content of the Galaxy.

e) If your N is very large---as it will be if you're desperately subdividing your moons into pebbles, or (worse) into diffuse gas clouds, to escape the microlensing bounds---then your dark matter is colliding like crazy and can't possibly remain on the halo orbits where the non-disky gravity is coming from.

f) In any case, no matter what your X is, if it's found on the Periodic Table then it is inconsistent with the CMB acoustics.

g) In any case, no matter what your X is, if it's found on the Periodic Table then it is inconsistent with the BBN.

There you go, MM. We have considered, in a standard scientific way (present hypothesis, evaluate observables, compare to data) the baryonic dark matter hypotheses. I believe we have discarded all possible baryonic dark matter hypotheses via observations a-e, and triply discarded them if we include f and g(which we do).

The possible exception would be a incredibly numerous sort of sub-lunar-mass-black-hole-population---let's call it the "X=neutronium, M < 10^22 kg" hypothesis, not that you have ever suggested such a thing. Maybe not ruled out by data. X and Y picked out of thin air to avoid lensing bounds. Yep, that's crazy-arbitrary curve fitting in the service of avoiding SUSY. How do you like it? Quite frankly, physicists would be considered this incredibly more exotic and crazy-speculative (how the heck would Nature make such a thing?) than SUSY, axions, and walking technicolor put together.

We didn't reject baryonic dark matter because we love inventing new particles. We rejected it because Nature rejected it, and has given us plenty of evidence that she rejected it. Nature has not YET given us evidence for exactly what she did instead. But we're looking.

 

[Pythonic]

As a non-participant, I can't answer that.

As a non-physicist lurker, however, I can report that I have learned a number of things by following this thread, and that it has been far more interesting than reading Bjarne's threads. It isn't hard for lurkers to figure out which participants know what they're talking about, and which participant can be ignored.

Will

I couldn't agree more. I'm a non-physicist lurker and have gained a lot going through this (and its predecessor) thread.

 

[phunk]

And in his model "dark matter" would be located in "flying electrons and flying electric ions of all kinds."

Free electrons & ions is what we call plasma. The amount needed to account for the observed gravity would be very visible.

So we don't even have the technology to see something the size of Earth in our *OWN* galaxy, and you expect me to believe we can account for all the mass in galaxies that are millions of light years if not billions of light years away? Don't you find that the least bit "hard to swallow"?

There could be thousands of planets around every star and it wouldn't come close to adding up to the missing mass.