Fermi and dark matter

It's essentially impossible to stay on topic in a discussion with MM. His view of science differs so radically from that of scientists, and his ignorance of the relevant physics is so complete, that it's not really possible to maintain a discussion without it falling into one of the many gaps that creates.

Still, the thread was probably doing better without me and I'm basically uninterested in reading anything MM writes, so perhaps it's better I bow out of it.
 
Michael Mozina said:
This is what I mean about EU theory being the "evil topic" in astronomy these days. On most topics of conversation I have found you personally to be very (extremely) reasonable and very rational. That particular comment however is simply and utterly absurd. EU theory has enjoyed both mathematical and empirical support since the work of Kristian Birkeland. It was 'refined' in it's mathematical descriptions by Dr. Charles Bruce and expressed in MHD theory by the guy the wrote MHD theory, and his first generation students. There's a ton of mathematical quantification to be found in Alfven's work alone.

http://adsabs.harvard.edu/cgi-bin/n...eq=no_params&author=Alfven, Hannes&db_key=AST
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So EU theory is quantified in the bits of EU theory which are (apparently) the same as "mainstream" science. Ok.

Just out of curiosity, have you even bothered to read the book Comic Plasma?
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No.

What is it with you guys and the irrational hostility towards EU theory? You do not treat EU/PC theory like any other mathematically quantified theory, not like MOND theory, not like any of your metaphysically enhanced "big dark inflated bang" theories. What's up with that?
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Because MOND doesn't tend to contain ridiculous ideas like magnetic fields are responsible for the Suns rotation around the galactic centre? Or the surface of the Sun is made of iron? Or that there's a neutron star in the centre of the Sun perhaps?

On most topics of conversation you seem to be highly educated on the topic and right on the money with your statements. On this topic however you begin with a ridiculous claim that ignores the whole history of this theory going all the way back go Birkeland. Birkeland by the way "predicted" (real empirical predictions by the way) "coronal loops", "jets", "high speed solar wind" and all the things that still perplex 'modern (dark age) astronomy" today.
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To the best of my knowledge, the stuff Birkeland predicted that bore out to be true became good old "mainstream" physics. The stuff that was wrong was forgotten about.

Your response seems to be an emotional knee jerk reaction, and one based entirely on ignorance of history. I respect you a great deal which is why I'm telling you on this topic you're dead wrong.
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The way to actually prove your point would be to show us all a quantitaive EU alternative to dark matter.

Oh baloney. When your BB numbers have been off by OOMs, you simply added something "dark" into the batter or stirred in a dead and invisible inflation deity into the math.
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The evidence for these things come from observation. If you have a better theory that fits the observations with the same number or fewer free parameters then please feel free to explain it to us.

Astronomers have then tried to sweep their glaring failures of the past under the carpet with comments like:

"See look how well our new and improved metaphysical dark-inflation theory "predicts" what we observe in space?" It's like watching the Fox news channel of astronomy. You folks seem to have blatantly ignored every single failed prediction that ever happened. Astronomers tend to ignore the historical reality that BB theory has *NEVER* accurately matched 'prediction". It's been "postdicted" together with metaphysical band-aids since Guth started the trend back in the early 70's. It's been down(metaphysical)hill ever since.
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Wrong. For example, the BB theory predicted the line-shape of the CMBR and agreement has been found to an absolutely extraordinary precision.

EU does in fact suffer from a critical handicap in terms of "competing" with metaphysics. It is restricted to what *can* be physically and empirically demonstrated to work in lab. One is of course allowed to "scale" a known and demonstrated process, but in EU theory you can't toss "magic energy" into the equations.
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Can you demonstrate neutron stars in a lab? Or even just neutron degenerate matter?

It therefore takes a bit longer to work out a 'real solution' based on real (empirical) physics.
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The measurement of the CMBR was real empirical physics. Its agreement with the "mainstream" cosmological paradigm is just stunning.

On this topic, I'm willing to be patient and put my trust empirical physics.
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Perhaps your EU theory could explain the empirical CMBR observations then?

On the other hand I have no faith at all in 96% of current theory or any of the dead inflation deities to choose from these days.
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There are no "inflation deities", alive or dead.
 
sol invictus said:
It's essentially impossible to stay on topic in a discussion with MM. His view of science differs so radically from that of scientists, and his ignorance of the relevant physics is so complete, that it's not really possible to maintain a discussion without it falling into one of the many gaps that creates.

Still, the thread was probably doing better without me and I'm basically uninterested in reading anything MM writes, so perhaps it's better I bow out of it.
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I disagree SI, it was just a request as this thread has reached a point where discussion is occuring, your input is always interesting.

That was a general request to all posters, not to any poster in specific.
 
sol invictus said:
There is for once an element of truth to that. Electromagnetism and classical gravity are extremely well-understood theories. The quantum version of E&M in particular is in a specific sense the best-tested scientific theory in the history of the human race. As a result, we know absolutely for certain that EU is a complete and utter failure at describing the universe.
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That comment wouldn't sound so utterly ironic were it not for the fact that
"modern" astronomers cannot explain something as simple as sustained high energy coronal loops, solar jets, and high speed solar wind, something that was "explained" and "predicted" by Birkeland over 100 years ago.

It's not even close, it's not even in the ballpark, and we can be so confident precisely because we understand E&M so very well.
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Ya, astronomers know it so well in fact that they still practice a form of what Alfven himself called "pseudoscience". More importantly they can't/won't (refuse to) recognize a "discharge' in solar plasma when they see one. No wonder they "failed" so miserably to explain the universe with electricity and gravity. They keep calling an electrical discharge process a "magnetic reconnection" process and treat the whole thing as a "neutral" plasma.

Theories of dark matter, on the other hand, are far less well understood. Really there's a family of theories, a few of which might succeed in accounting for the current data. Since the rules are much less well known, there is indeed much more "wiggle room".
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Indeed. It is 100% ad hoc wiggle room in fact and only the most recent installment of metaphysics into BB theory. Without it, gravity theory (without electricity) is indeed a miserable failure at describing the universe. Dark matter and dark energy are essentially fudge factors of epic proportions and with inflation providing the last of the metaphysical 'wiggle room' anyone will ever need to explain anything. Need gravity to do repulsive tricks? No problem. Need "space" (physically undefined no less) to "expand" somewhere out there we we can never reach, but have no effect here on Earth? No problem! Need to account for faster than light expansion from a single lump? No problem. Need an "accelerating' universe when you first 'predicted' a decelerating one? No problem. That "new and improved" BB theory has all the fine wiggle room a mathematician could ever ask for.

Lambda-CMD theory today is 96% "wiggle room" and only 4% actual physics. Is it any wonder that the numbers can be fudged to fit anything and everything? The last time it didn't "fit right" BB theory was stuffed with 70%+ more metaphysics, and that was just in the last 12 years or so. Holy cow, if we never have to physically demonstrate anything, "magic energy", "magic matter", and "magic inflation" do exactly the same "excellent job" of describing the universe.
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Tubbythin said:
So EU theory is quantified in the bits of EU theory which are (apparently) the same as "mainstream" science. Ok.

No.
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That's too bad IMO. IMO that is one of the more important books ever written on astronomy, Birkeland's work being *the* most important IMO.

Keep in mind that what Birkeland, Bruce and Alfven attributed to "electrical discharges" in plasmas, the mainstream now calls "magnetic reconnection". Alfven personally rejected that term as pseudoscience, but what does he know, he just wrote MHD theory. Only grudgingly has the mainstream "accepted" the parts of EU theory they could not live without, like Birkeland's aurora "predictions".

Note that all of Birkeland's "predictions" were actually, real and true predictions that were derived from empirical experimentation. He actually learned things from his experiments and wrote about them. His theories all worked in the lab too.

Because MOND doesn't tend to contain ridiculous ideas like magnetic fields are responsible for the Suns rotation around the galactic centre?
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You have some odd ideas about what EU theory is by the way. I've never even heard of that one before. Most EU proponents use the term "electromagnetic field", and yes most of us believe that current flows "could have an influence" on the galactic rotation pattern. I don't think anyone claims that gravity isn't also important or relevant in the process.

FYI, one could call MOND theory "ridiculous" simply for claiming that GR theory was invalid. It's all a very subjective call.

Or the surface of the Sun is made of iron? Or that there's a neutron star in the centre of the Sun perhaps?
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I think it would be better to stay on topic in this thread and keep this on focused

To the best of my knowledge, the stuff Birkeland predicted that bore out to be true became good old "mainstream" physics. The stuff that was wrong was forgotten about.
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Unfortunately for the mainstream they rejected parts of Birkeland's theories that were also "right", like those solar atmospheric discharges they keep calling "magnetic reconnection". They seem to ignore the fact that he actually "predicted" those jets and solar wind particles that the mainstream still struggles with.

The way to actually prove your point would be to show us all a quantitaive EU alternative to dark matter.
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Did you ever check out any of Peratt's work by any chance? He attempted to create a computer model to mimic the behaviors of plasmas on a large scale and succeeded in creating many of the same galaxy type structures we observe in space. Pure coincidence in your opinion? Now I personally have reason to believe that a "missing mass" alternative is probably more viable than this simply being a result of an EM influence. The lensing data does convince me that a "missing mass" theory is preferable over a MOND theory or even an EU oriented option theory per se. That does not mean I believe that any of the missing matter is contained in exotic SUSY particles.

The evidence for these things come from observation. If you have a better theory that fits the observations with the same number or fewer free parameters then please feel free to explain it to us.
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I'm actually complaining about the fact that astronomers 'created' the parameters in an ad hoc manner, they did not use a known parameter or a know force of nature. That's been done now on at least three occasions in just the last 35 years or so. First we got inflation, then exotic forms of dark matter, and the most recent addition now makes up 70%+ of the whole universe no less! Your parameters are a little "too free" for my liking. :)

Wrong. For example, the BB theory predicted the line-shape of the CMBR and agreement has been found to an absolutely extraordinary precision.
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With or without, inflation, dark energy and dark matter?

Can you demonstrate neutron stars in a lab? Or even just neutron degenerate matter?
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I can't technically build a completely working star in a lab, no, but then I'm not asking you to do that either. I can empirically demonstrate that neutrons exist in nature and that gravity has an effect on them. That's a lot more than you can do with "dark matter". :)

The measurement of the CMBR was real empirical physics. Its agreement with the "mainstream" cosmological paradigm is just stunning.
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It's "stunning" to me that you find it "stunning" that a constantly modified and postdicted theory, filled with metaphysical fudge factors galore, actually matches observation with some precision. :)

Perhaps your EU theory could explain the empirical CMBR observations then?
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Nope. Neither can you without fudge factors galore starting with inflation.

There are no "inflation deities", alive or dead.
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The really incredible thing to me about modern Lambda theories is the fact that they all rely upon inflation and you all accept the notion that inflation doesn't exist anymore, just "once upon a time". That makes this theory about as close to a deistic religion as one could possibly make it IMO.
 
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How would "normal clumpy matter" (MACHO) behave any differently than any of the "dark matter" in those blue blobs? How exactly could anyone (pick any paper you like) differentiate ordinary "MACHO" dark matter from "non baryonic" matter in that region?
 
Michael Mozina said:
Sure. In your opinion, what's keeping the ICM at extremely high temperatures "normally" (in other words, forget collisions for the time being)?
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As stated twice before:
Intracluster medium
Heating
The ICM is heated to high temperatures by the gravitational energy released by the formation of the cluster from smaller structures. Kinetic energy gained from the gravitational field is converted to thermal energy by shocks. The high temperature ensures that the elements present in the ICM are ionised. Light elements in the ICM have all the electrons removed from their nuclei.
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http://www.astronomy.com/asy/default.aspx?c=a&id=4245

As Tubbythin pointed out earlier, it can be very difficult even determining how much 'normal matter' is contained in our own galaxy. It's therefore not the least bit surprising to me that we have a difficult time accounting for all the mass in a distant galaxy. I still see no evidence that any of these lensing or rotational "methods" provides us with any insight into the actual composition of the mass.
 
Can Micheal Mozina answer a simple question about intercluster medium

Since MM is obsessed with the interstellar meduim, stars and solar systems, MACHOS, and everything else except what the observations actualy are, I have emphasised yet again that this question is about the intercluster medium (ICM) (original question in this thread here).

First asked 18 July 2009

First a few science points to hopefully preempt the straw man arguments that MM has been raising.
  • This question is about the collision of the intracluster medium in colliding galactic clusters.
  • The intracluster medium is
    In astronomy, the intracluster medium (or ICM) is the superheated gas present at the center of a galaxy cluster. This plasma is heated to temperatures of between roughly 10 and 100 megakelvins and consists mainly of ionised hydrogen and helium, containing most of the baryonic material in the cluster. The ICM strongly emits X-ray radiation.
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  • MM: the intracluster medium is not galaxies, stars, solar systems, MACHOS or black holes.
  • This is not very relevant to the question but: a typical galactic cluster has about twice as much mass in the intracluster medium as it does in its galaxies.
  • The mean free path of the particles of the ICM is about 1 lightyear. This means that these particles (whether charged or neutral) will collide over 3 million times when passing through a ICM cloud or blob with a typical thickness of 1 megaparsec.
Here is the question about the intercluster medium in colliding galactic clusters:
  1. A is a big blob of gas with the same size and density of the ICM in a galactic cluster.
  2. B is a bib blob of gas with the same size and density of the ICM in a galactic cluster..
  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. See the point below about why insignificant amounts of normal (baryonic) matter will 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 in the bolbs A and B.
  5. Thus the gas is made of two kinds of gas, one of which interacts weakly with the other.
Any problems with this analysis with what is going on with the majority of the matter (i.e. ICM) in the Bullet Cluster and MACS J0025.4-1222 (and even Abell 520)?

Remember that astronomers can calculate the probability of atoms in the ICM colliding as they travel millions of light years through each cluster. I do not know the exact number but expect it to be high (an atom travels millions of light years through a medium containing about 1 atom per cubic meter - you do the math!).


It has become obvious that you cannot do the math so here is it:
  • The intracluster medium (or intergalactic medium):
  • The Bullet cluster is at least 1 megaparsec in width 3,261,6366 lightyears.
  • That means that normal baryonic particles collide over 3 million times to pass from one side to the other. Neutral particles collide as much as ionized particles.
  • Normal baryonic particles that collide heat up. Normal baryonic particles that heat up in the ICM produce X-rays that can be detected as in the rest of the Bullet Cluster.
Thus the amount of gas that did not collide is tiny (less than one part in a million and that is being generous). The outlying blobs are thus mostly weakly interacting gas, i.e. particles that collided but did not interact strongly.

If you cannot find any problems then you agree that these three observations are evidence that there is matter that does not interact like baryonic matter. This we call nonbaryonic matter.
 
Reality Check said:
I do not know. Ask an astronomer.
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I see. Whereas electrical current is *known* to cause plasma to heat up to high temperatures and cause them to emit gamma rays and x-rays, "gravitational energy" is virtually non-existent at these distances from the various galaxies. I suppose this *could be* another of those nifty astronomy euphemisms for "fast moving charged particles", in other words: "current flow". :)
 
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So let's see....

We observe gamma rays from Earth that are directly linked to electrical discharges in the Earth's atmosphere. We point the same equipment at the sun, see the same annihilation signatures and we call it "magnetic reconnection"? Huh?

Either way you look at it folks annihilation signatures are completely 'natural' and they come from "normal matter". These emission wavelengths occur "naturally' inside our solar system. There simply is no need for any form of exotic matter to explain annihilation signatures from space, just 'current flow' and normal matter that is located on physical bodies like planets and suns. There is no way in hell that a "dark matter' explanation of annihilation wavelengths in space is going to survive a simple Occum's razor argument.
 
Reality Check said:
The mean free path of the particles of the ICM is about 1 lightyear. This means that these particles (whether charged or neutral) will collide over 3 million times when passing through a ICM cloud or blob with a typical thickness of 1 megaparsec.
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Could you point me to the page and paper where that number was calculated?
 
Michael Mozina said:
What specifically does this statement mean:



How come this plasma is hotter than the interplanetary plasma?
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When two objects collide inelastically, they convert bulk kinetic energy into heat. The more bulk kinetic energy, the higher the final temperature. Galaxy clusters are very massive, so infalling gas is coming in very fast, hence has a lot of kinetic energy, hence a high temperature. One also has to ask how efficiently a high-temperature gas can cool down or escape, as this should also affect the observed temperature.

This tells you that more massive clusters (=more kinetic energy) should be hotter than less massive clusters. It does not tell you whether clusters should be hotter than the ISM, or hotter than the solar wind, or hotter than the fluorescent light bulbs in my office, or hotter than ITER, because there are different energy sources (and different cooling mechanisms) in these different places.
 
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