Is Dark Matter for real?

[sabianq]

"Explanation of the whirlpool galaxy from constant space-time torsion:
the case against dark matter"

ECE unified field theory?

http://aias.us/documents/uft/a123rdpaper.pdf

[Jerry]

http://arxiv.org/abs/1001.4836

[/quote=too many authors]
The limits on hvi (hvi Z) shown in Table I are about one or more orders of magnitude weaker than the cross-sections expected for a typical thermal WIMP. However, there are several models in the literature that predict larger cross-sections and are constrained by these results.[/quote]

... So WHIMPs are either non-existant or extremely WHIMPY.

[Kwalish Kid]

And the quotation continues;

However, there are several models in the literature that predict larger cross-sections and are constrained by these results. A WIMP produced non-thermally may have a much larger annihilation cross-section than a thermally produced WIMP and still produce the required DM relic density. An example is...

As usual, you have provided us with a paper that doesn't threaten the standard cosmological model.

[Jerry]

Of course not. How would one disprove dark matter exists? The search for WHIMPS is not unlike the radio band searches a century ago for messages from angels, or the SETI searches of the last few decades. We can't prove there are not angels or aliens either.

But with each progressive constraint, the possibility that the 'dark matter' explanation for mass behavior is wrong increases. Nancy defined 'dark matter' as a 'place holder' for something we do not understand. It is good to keep searching, but more emphasis needs to be placed upon verifying that the fundamental assumptions are sound.

[sabianq]

isnt that why we call it "Dark" Matter?
cause we dont understand it? not because we cant see it??

[loglo]

"Explanation of the whirlpool galaxy from constant space-time torsion:
the case against dark matter"

ECE unified field theory?

http://aias.us/documents/uft/a123rdpaper.pdf

It is well known that the now obsolete Einsteinian general relativity omits consideration of space-time torsion, and in so doing uses an incorrect symmetric connection [1]- [10] with multiple sequential mathematical errors that render the theory meaningless in physics

Yeah , right.

[Nereid]

It gets better.

The document's authors are M. W. Evans and H. Eckhardt.

The authors of [1]-[10] are?

Well, M. W. Evans is the sole, or lead, author of [1], [4], [5], [6], [8], [9], and [10] (and H. Eckhardt the second author of [10]).

[2] is titled "The Evans Equations of Unified Field Theory", and [3] "The Life of Myron Evans".

[7] is "ECE Papers and Archives on www.aiais.us".

I guess M. W. Evans knows something well.

And what is aiais? Why it's the "Alpha Institute for Advanced Study", which its website describes as "among the leading theoretical physics institutes worldwide".

[loglo]

I tried applying the Baez crackpot index to their webpage, I lost count. A comprehensive refutation to ECE is here.

[Jerry]

So by definition, if you reject the currently most poplular explainations for why Newtonian and Einsteining physics are failing, you get crackpot points for 1) Mentioning their names, 2) starting with the assumption that GR and QM cannot be reconciliated because they are both fundamentally flawed.

[loglo]

So by definition, if you reject the currently most poplular explainations for why Newtonian and Einsteining physics are failing, you get crackpot points for 1) Mentioning their names, 2) starting with the assumption that GR and QM cannot be reconciliated because they are both fundamentally flawed.

No, but you do for calling GR redundant, every physicist who criticises your work wrong or on a personal crusade and are consistently ignored in the relevent literature but still persist in peddling a discriedited theory.

[noncryptic]

This seems the right place to ask about an issue with Dark Matter that has been bothering me for a while:


A large enough cloud of (non-ionized) baryonic matter particles/atoms will gravitationally collapse into stars etc.

But apparently a similar size cloud (or even a much larger cloud) of Dark Matter, although it does "clump", it does not gravitationally collapse (into stars etc).

How does the Dark Matter working hypothesis explain that phenomena?

[StupendousMan]

This seems the right place to ask about an issue with Dark Matter that has been bothering me for a while:


A large enough cloud of (non-ionized) baryonic matter particles/atoms will gravitationally collapse into stars etc.

But apparently a similar size cloud (or even a much larger cloud) of Dark Matter, although it does "clump", it does not gravitationally collapse (into stars etc).

How does the Dark Matter working hypothesis explain that phenomena?

Short answer: dark matter interacts only weakly with itself and with normal matter

Longer answer: Suppose a cloud of ordinary hydrogen gas begins to collapse due to its own self-gravity. Molecules of hydrogen will bump into other molecules of hydrogen -- meaning the electric forces between their components (electrons and protons) become large enough to alter the motions of the molecules, and also cause the atoms to jump to higher energy states. Some of the atoms which have been excited will radiate the energy away as electromagnetic radiation. Some of the initial kinetic energy of the molecules escapes the cloud as radiation. Since the gas in the cloud now has less kinetic energy, and the molecules are moving more slowly, they cannot move as far away from the gravitational potential well at the center of the cloud, and the cloud shrinks.

(Warning: very simplified version of physics in above explanation. I don't have time to write a full chapter on the processes)

Now, suppose that there's a cloud of dark matter particles. Physicists assume that dark matter particles do NOT interact via the electromagnetic force with ordinary matter or with each other -- but only by the gravitational force. That means that when two dark matter particles happen to fly past each other, they do not exert strong forces on each other. The particles cannot easily radiate away any of their energy, either. The result is that the cloud does not shrink, since the particles cannot rid themselves of their initial kinetic energy.

(Warning: again, simplified physics)

[noncryptic]

Thanks for explaining, mr Stupendous.
I now realize that i underestimated the importance of E/M / atomic forces in the condensation of normal matter.

[borman]

Strain for Universal Theory

Dark Matter is invoked to allow GR to explain the motions of stars in galaxies and motions of galaxies in clusters. This requires large halo distributions of unseen non-baryonic matter that observes the same gravitational laws that baryonic matter observes. This permits GR to explain all over this large realm.

To remain universal over the same realm, but not invoke Dark Matter, would otherwise require modifications of the Newtonian gravity or GR. This would augment GR with a combination of Tensors, Vectors, and Scalars or put a transition limit on how gravity behaves at threshold accelerations. There is a further requirement to restore to GR at the proper limit to remain consistent with observations at the solar system level. At some point there must be some deviation from classical GR. Some of these theories will likely be falsified when GR accuracy is pressed to 16 decimals with upcoming tests such as STEP.

A possible third option is to not insist on one universal theory to cover the entire realm but there are additional theories for different aspects of the entire realm. From this perspective, GR is a rather precisely correct theory for its subrealm and is in no need of modification nor Dark Matter for it to work completely well within its domain without the Lambda term. To explain the other inertial phenomena observed that appear anomalous with respect to GR, such as Dark Matter, Dark Energy, and Large Scale Structures, would require additional theories rather than modified theories or unknown energy densities to be added to GR.

[Jerry]

http://www.ligo.caltech.edu/LIGO_web...factsheet.html

More specifically, LIGO has the possibility to:

•Verify directly general relativity's prediction that gravitational waves exist.
•Test general relativity's prediction that these waves propagate at the same speed as light, and that the graviton (the fundamental particle that accompanies these waves) has zero rest mass.
•Test general relativity's prediction that the forces the waves exert on matter are perpendicular to the waves' direction of travel, and stretch matter along one perpendicular direction while squeezing it along the other; and also, thereby, test general relativity's prediction that the graviton has twice the rate of spin as the photon.
•Firmly verify that black holes exist, and test general relativity's predictions for the violently pulsating space-time curvature accompanying the collision of two black holes. This will be the most stringent test ever of Einstein's general relativity theory...

Last modified October 2, 2001

The fact is, LIGO found nothing. GR is failing it's most stringent test. I know everyone has a but: But Advanced LIGO will see so much further -ten times further. It has been more than a year since the LIGO Collaboration has updated the blog or issued a new release. You have to have a password to even look at the program for the March 2010 LIGO consortium meeting. More mips have flopped searching for gravity waves than for every other cosmic phenomenon combined. Optimism is waning.

http://ligonews.blogspot.com/

http://www.ligo.org/conferences/lv0310/program.shtml

[Kwalish Kid]

What does your standard rant against GR have to do with this thread?

[Jerry]

What does your standard rant against GR have to do with this thread?

Read the prior post:

"Dark Matter is invoked to allow GR to explain the motions of stars in galaxies and motions of galaxies in clusters."

But now, we need an additional explanation, for why we can't observe the gravitational perturbations predicted by GR. Perhaps the Dark Matter envelope dampens gravitational waves. As long as you are happy with a place-holder that only reacts gravitationally, you might as well give it some padding.

[Kwalish Kid]

That's an interesting couple of straw-men you have there.

[borman]

But now, we need an additional explanation, for why we can't observe the gravitational perturbations predicted by GR. Perhaps the Dark Matter envelope dampens gravitational waves. As long as you are happy with a place-holder that only reacts gravitationally, you might as well give it some padding.

If one were to assume that spacetime had microstructure, the energy from binary decay could be going into heating the horizon.

Thermodynamical Aspects of Gravity: New insights

http://arxiv.org/abs/0911.5004