Dark matter could provide heat for starless planets

Apr 01, 2011 by Deborah Braconnier report

(PhysOrg.com) -- In a recent paper posted at arXiv.org and submitted to Astrophysical Journal, Dan Hooper and Jason Steffen, physicists at Fermilab in Illinois, present the theory that cold and dark planets, not heated by a star, could be heated by dark matter. In theory, this dark matter could produce habitable planets outside of what is known as a habitable zone.

While no one knows exactly what dark matter is, it is believed to make up about 83 percent of the . The most accepted theory is this dark matter is made up of what are called WIMPs, or weakly interacting massive particles.

These WIMPs interact with regular matter by a weak nuclear force and gravity, but they are also antiparticles. When two WIMPs come together, they work to annihilate each other and cause a burst of energy.

Hooper and Steffen suggest that should this dark matter be trapped within a planet’s , the bursts of energy could produce enough to warm the planet. When it comes to Earth, the energy that could be produced is low, but in areas of space where there are high densities of black matter; Hooper and Steffen believe there is the possibility of finding planets that could be warmed in this way.

Within the innermost regions of the Milky Way, density of dark matter is estimated to be hundreds or thousands of times that in our solar system, and it is in these areas that Hooper and Steffen believe finding a planet heated by dark matter would be most plausible.

Traditional planets, heated by stars like our sun, are dependent on the life of that star. This theory would make these dark matter planets have a large advantage over those tied to a star, as the dark matter could provide heat for trillions of years.

Hooper and Steffen admit that they currently do not see a way of detecting any of these possible planets in the near future, but that in theory, it is possible.

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More information: Dark Matter And The Habitability of Planets, Dan Hooper, Jason H. Steffen, arXiv:1103.5086v1 [astro-ph.EP] arxiv.org/abs/1103.5086

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Moebius
2.9 / 5 (27) Apr 01, 2011
Hooper and Steffen admit that they currently do not see a way of detecting any of these possible dark matter planets in the near future, but that in theory, it is possible.


I have a theory that Hooper and Steffen suffer from an unknown form of insanity. There is currently no way of detecting this form of insanity but in theory it is possible.
newsreader
4.6 / 5 (18) Apr 01, 2011

I assume this is an April Fool's joke. If not we may have another explanation for global warming.
Modernmystic
1.8 / 5 (18) Apr 01, 2011
The only way I can see this happening is the increased internal pressure created by the increased gravity acting on the planet...otherwise I'm having a hard time swallowing this.

Dark matter only interacts gravitationally and can't transfer heat to regular matter in any way shape or form...assuming it's even "warm" to begin with.
Pyle
2.9 / 5 (15) Apr 01, 2011
Mm: This was posted to arxiv on the 25th. The paper is real.

However, I think, the paper is based on unverified properties of dark matter. In particular, their assumptions regarding DM anti-DM annihilation seems to rest on very shaky ground. The work is good work, but the assumptions and utter lack of observation to support them make it quite the trip down fantasy lane. If their hypothesis of dark matter in their assumptions is correct then their conclusions about heating planets in dense DM regions might warrant exploring.

Cool paper though. Good stuff. Just not very close to provable or usable until we get a better handle on DM, if it even exists (go MOG!).
El_Nose
2.3 / 5 (3) Apr 01, 2011
newsreadr i gave you a 5 for funny
ShotmanMaslo
3.7 / 5 (10) Apr 01, 2011
Dark matter only interacts gravitationally and can't transfer heat to regular matter in any way shape or form...assuming it's even "warm" to begin with.


When dark matter annihilates, it creates a burst of energy (gamma rays?). This is where the heat should come from.
Modernmystic
1 / 5 (8) Apr 01, 2011
Dark matter only interacts gravitationally and can't transfer heat to regular matter in any way shape or form...assuming it's even "warm" to begin with.


When dark matter annihilates, it creates a burst of energy (gamma rays?). This is where the heat should come from.


It doesn't emit ANY EM radiation at all...that's why it's called dark matter...
Pyle
3.3 / 5 (16) Apr 01, 2011
When dark matter annihilates, it creates a burst of energy (gamma rays?). This is where the heat should come from.

It doesn't emit ANY EM radiation at all...that's why it's called dark matter...

This article is assuming some hypothesis of DM in which there are DM WIMPs floating around with anit-DM WIMPS that will annihilate and release radiation. ShotmanMaslo has it right.

This is all based on a guess as to what is causing certain astronomical observations such as galaxy rotation and galaxy cluster behavior. Dark Matter is a plug and there are several hypothesis regarding its nature, of which this study assumes one, namely WIMPS. The assumptions used for this study stem from the most commonly accepted explanation currently. LHC should shed more light on DM.
Callmewhatuwant
1 / 5 (3) Apr 01, 2011
ooo....annihilation=radiation=heat-...??? i guess....nice....interesting work...
71STARS
2.1 / 5 (15) Apr 01, 2011
This is the most ridiculous piece of drivel to ever come across this site. And they had their "paper" submitted to Astrophysical Journal?? This goes to show how these reviewing magazines who supposedly have credentials for producing reliably work have fallen into an abyss!

These two men have no idea what causes Dark Matter, no idea what its chemical makeup is, no idea how an unknown substance would interact with any planetary bodies, and yet -- they submit a paper ALL about it. Incredible!!

To admit you don't have the faintest clue as to what Dark Matter is and then submit your paper on your "fantasy idea" of what it will do to "planets" in the Universe, now that would set up the article correctly. And where is their proof that there is any radiation in a Dark Matter scenario? Pure drivel.
dogbert
1.8 / 5 (20) Apr 01, 2011
Speculations such as this article are the result of using a kludge to "fix" what we observe gravitationally on stellar scales and then actually believing in our kludge.

If even a fraction of the effort which is spent on "proving" the existence of dark matter went into discovering why gravity does not behave as we expect on stellar scales, we would probably have a much better understanding of gravity.
Pyle
3 / 5 (17) Apr 01, 2011
71: This paper is backed by solid math and scientific observation. The hypothesis of DM WIMPs is solidly based on our observations and theoretical calculations. I agree that what this paper investigates is fantastical, as I pointed out previously. However, perhaps there is an idea here that can be extended to provide a way to test this DM hypothesis? Imagination isn't a bad thing when testing the limits of science.

dogbert:
If even a fraction of the effort which is spent on "proving" the existence of dark matter went into discovering why gravity does not behave as we expect on stellar scales...
Nonsense. How exactly are you proposing to discover this? Good luck with winning that Nobel Prize. If anybody knew where to focus energy to "discover" it they would be. Actually MOND and MOG are examples of where people are looking.
qazaq
1.5 / 5 (8) Apr 01, 2011
dark matter "...it is believed to make up about 83 percent of the universe..."
"Within the innermost regions of the Milky Way, density of dark matter is estimated to be hundreds or thousands of times that in our solar system"

YES! But only on April 1.
On all other days it is about 23 %.
Pyle
1.7 / 5 (6) Apr 01, 2011
gazag: Not to make excuses, but if you look at normal matter and dark matter I think 83% is about right for dark matter.
23% dark matter / 27.6% dark + normal matter = 83% of matter

Just saying. (I gave you a 5 for pointing it out though.)
dogbert
1.7 / 5 (16) Apr 01, 2011
Pyle,
dogbert:

If even a fraction of the effort which is spent on "proving" the existence of dark matter went into discovering why gravity does not behave as we expect on stellar scales...

Nonsense. How exactly are you proposing to discover this?


Like scientists discover anything else? Observe, develop hypotheses, test, etc.

Certainly not by believing in a kludge.
eachus
4.6 / 5 (10) Apr 01, 2011
Remember how the scientific method works. 1) Propose a theory. 2) Design tests which may falsify that theory. 3) Perform tests. 4) If any test falsifies the theory, time for a new theory. Otherwise (provisionally) accept the theory. Not all these steps have to be performed by a single scientist, and decades can pass between proposing a theory and someone proposing an experiment that can test the theory. Decades more can pass before tests are feasible and performed.

How do (real) scientists keep track of which theories deserve testing? Easy, any theory that has not been falsified (and can be) deserves testing. Theories that have been accepted for hundreds of years keep getting subjected to new and more sensitive tests.

This paper is proposing a theory which, although not currently testable, may be testable (and tested) in the future.
heliumblue2
5 / 5 (1) Apr 01, 2011
I have been following this site for a long time, but this is the first comment I am submitting.

While I do admit this is a bit challenging to accept; I do believe that Pyle has the right approach to this. LHC should shed some better light on this as things progress.
Etreum
5 / 5 (2) Apr 01, 2011
Reality is stranger than fiction.
Wulfgar
not rated yet Apr 01, 2011
I have a naive question. Dark matter is supposedly matter that only interacts with ordinary matter gravitationally, correct? So is there matter out there that only interacts electromagnetically with ordinary matter and not gravitationally? I would think that if dark matter exists, then such other matter would also exist.
Sam_Herzig
2 / 5 (4) Apr 02, 2011
Dark matter makes up 83% OF THE UNIVERSE. COME ON!!!
LAST TIME IT WAS 70% AND 60%. WHAT THE HELL IS WRONG WITH THESE PREDICTIONS!!!
Pyle
3.2 / 5 (13) Apr 02, 2011
Certainly not by believing in a kludge.
Look up the story of the "discoveries" of the planets Neptune and Vulcan.

Hypotheses to explain observed phenomenon that are grounded in solid math are sometimes the right answer. Other times it takes a new theory to explain the observed phenomenon.

Whichever the case with DM your negativity isn't appreciated.

@Wulfgar: That would be matter with no mass. Photons?

@Sam Herzig: See my previuos post. Dark Matter is roughly 83% of the "matter" in the universe. This figure isn't considering the Dark Energy component.
ShotmanMaslo
3 / 5 (8) Apr 02, 2011
Like scientists discover anything else? Observe, develop hypotheses, test, etc.


Indeed, and that is exactly what they are doing, with dark matter hypothesis in this case. I dont think you, and other armchair astrophysicists, even comprehend how scientific method works, no offense. Ohterwise you would recognize that this is a nice example of how to do it.
Husky
4.4 / 5 (5) Apr 02, 2011
even if we consider this highly speculative construct, i don't think life would thrive on gamma radiation, if there somehow is enough gamma radiation to induce enough heat in the planet atmosphere it may cause too much ionizing damage for cells to evolve. Since the universe is incredibly big and diverse one cannot cpompletely rule out the slightest possibillity, but until actual supporting observations this seems like a highly artificial construct littered with ifs and buts, the substance of dark matter is not yet firmly grasped, so building a house of cards on top of it is like running a mile ahead in front of the music
dogbert
2.1 / 5 (19) Apr 02, 2011
ShotmanMaslo,

The concept of "Dark Matter" was created to "adjust" our models of gravity when it was noted that suns and galaxies do not move in accordance with our gravity models.

You may consider it scientific to create an imaginary substance to "balance" a flawed model, but it would make much more sense to try to find out why our models are not working.

There are many obvious flaws in the concept of DM -- that it cannot be seen, that it cannot be examined in a lab, that it does not interact with the universe at all except through gravity, etc. But the flaw which is most obvious and which cannot be denied is that scientists presume that there is always just enough DM in just the right places to account for whatever anomalies are observed. That is, not only do we have to use a kludge to "normalize" our models, we must kludge each and every observation of anything we choose to observe outside of our solar system.

dogbert
1.8 / 5 (19) Apr 02, 2011
continued ...

It is decidedly NOT scientific to fudge each and every observation to fit a model which is not working.
Ethelred
3.9 / 5 (11) Apr 02, 2011
This paper is proposing a theory which, although not currently testable, may be testable (and tested) in the future.
Seems to me that it IS testable.

Within the innermost regions of the Milky Way, density of dark matter is estimated to be hundreds or thousands of times that in our solar system, and it is in these areas that Hooper and Steffen believe finding a planet heated by dark matter would be most plausible.
Since there is nothing magic about planets then suns should be heated as well. Thus suns in the center of the galaxy should have a higher temperature to mass ratio than suns out where we are. The question is how much higher and would the difference be high enough to measure from here.

Ethelred
ShotmanMaslo
3.3 / 5 (9) Apr 02, 2011
dogbert - we do not know if our model of gravity works or not. There may be some modified equation that will explain the observations without dark matter. Or our current equations could be correct, and it may be dark matter which is responsible for the discrepancy. Both these hypotheses are scientific, and both should be pursued further, and indeed both are being researched.

I fail to see why the fact that dark matter is supposed to interact only gravitationaly is somehow a flaw. Such particle is not forbidden by our current knowledge, in fact, there are theries where it is predicted.
shadfurman
2.1 / 5 (7) Apr 02, 2011
while i love the theories, i feel like dark matter is becoming a faith-based science. to the best of my understanding; dark matter is a constant we need to make our understanding of physics work. since it is apparent that we are misunderstanding much of the physics of our universe, i fail to understand why we jump to the conclusion that dark matter actually exists. i see more evidence for the existance of a god than i do for dark matter; yet we spend large sums of money looking for this mythical matter.
jamesrm
2.5 / 5 (4) Apr 02, 2011
This article is in need of proofing, one of the worst I have seen on this site for a long time.
Dark Energy is supposed to make up 83%, Dark Matter 23% and the rest normal Baryonic matter, they even call it Black matter at one point in the article.

"These WIMPs interact with regular matter by a weak nuclear force and gravity, but they are also antiparticles." should say they are their own antiparticles.

I may not agree with the idea of dark matter and this article is amazingly badly written at least it doesn't presume Dark Matter is a Fact.

"it is }believed{ to make up about 83 percent of the universe"

rgds
James
sstritt
1 / 5 (3) Apr 02, 2011
@Ethelred,
Your idea is the most interesting comment so far. Well done!
Husky
5 / 5 (1) Apr 02, 2011
agreed ethelred is on to something, or perhaps proof that they are NOT on to something hehe, lets have a good peer through the scope
Modernmystic
1.4 / 5 (13) Apr 02, 2011
Well if dark matter is able to produce heat that reacts to normal matter via EM mechanisms then it ISN'T all that DARK is it?

You can't have your cake and eat it too, either it only interacts gravitationally and is dark or it interacts in other ways and we probably should have noticed this long ago and it isn't dark.

I stand by what I said as long as people are still calling it dark matter. Change the name and the concept and what they're saying could make sense.
Modernmystic
1.6 / 5 (14) Apr 02, 2011
I fail to see why the fact that dark matter is supposed to interact only gravitationaly is somehow a flaw.


Well it's a flaw because then it isn't DARK.

Calling a canary an elephant is a flaw...neh?
dogbert
1.4 / 5 (9) Apr 02, 2011
Good point. Should it be called "Invisible matter"?
Quantum_Conundrum
1.9 / 5 (13) Apr 02, 2011
Within the innermost regions of the Milky Way, density of dark matter is estimated to be hundreds or thousands of times that in our solar system, and it is in these areas that Hooper and Steffen believe finding a planet heated by dark matter would be most plausible.


I have a problem with this statement, because it contradicts the reason Dark Matter was proposed in the first place, which was to allegedly explain the alleged discrpancy in the motion of stars far from the center of the Galaxy.

Having the DM in a higher concentration in the Center of the Galaxy would most certainly NOT explain the motions of stars at all, which is why DM is proposed to exist in a HALO outside the center of the galaxy, among the stars themselves.

So right away, either this article is wrong and ridiculous about the facts, or else the DM theory is instantly shown to be internally inconsistent.
ShotmanMaslo
3.7 / 5 (6) Apr 02, 2011
I fail to see why the fact that dark matter is supposed to interact only gravitationaly is somehow a flaw.


Well it's a flaw because then it isn't DARK.

Calling a canary an elephant is a flaw...neh?


Indeed, dark matter is in fact, invisible, not dark.. :D

Well if dark matter is able to produce heat that reacts to normal matter via EM mechanisms then it ISN'T all that DARK is it?


Indeed, and gamma rays or other particles from dark matter annihilation are being searched for:

http://en.wikiped...eriments
SincerelyTwo
not rated yet Apr 02, 2011
I am really confused, but maybe that's because I've learned about dark matter from very layman sources. As I've understood it there is no interaction between dark matter and the matter of which we and the /visible/ universe is composed.

But dark matter can bend space-time causing lensing. Now apparently dark matter can radiate heat? As I understand the annihilation of matter and anti-matter would be nearly instantaneous, which doesn't suggest there could be a relatively slow and continuous annihilation process, especially slow enough to emit a continuous stream of heat/gamma rays/etc.

I'm confused even more now, is anti-matter/matter annihilation an interaction? So the two forms of matter do interact? I feel like I'm hearing contradictions from every possible perspective.

If you ask me I feel convinced that the only thing we can actually say with confidence is that EM radiation does not interact with dark matter and dark matter bends space-time giving rise to gravitational force.
Modernmystic
1 / 5 (8) Apr 02, 2011
Indeed, dark matter is in fact, invisible, not dark.. :D


If it's not dark it's visible. Infrared light may not be able to be seen by the human eye, but we can still "see" it.

Again, you can't have it both ways. QC and Eth brought up very good points about the HUGE holes in this theory. My problem is somewhat with semantics, but it also bleeds over into the fact that something that's supposedly undetectable except for the gravitational effects hasn't been detected until now. It stretches credulity.

Moreover why should dark matter be any different than matter if it was all created in the big bang it would have had virtually zero distance between it and it's anti-dark matter counterpart. There should have been virtually complete annihilation of one or the other at the beginning. Why should extreme densities produce reactions based on annihilations that shouldn't be happening...

TheGhostofOtto1923
2.5 / 5 (11) Apr 02, 2011
So right away, either this article is wrong and ridiculous about the facts, or else the DM theory is instantly shown to be internally inconsistent.
I think I would tend to side with fermilab physicists who submit papers to journals, and assume that it is probably you who are wrong and ridiculous, and internally inconsistent, for reading the little news blurb above and assuming you know enough about a subject, to dismiss what these trained professionals have to say.

What do you think? What did you say your degree(s) were in? Where'd you do your post-doc?
soulman
4.2 / 5 (10) Apr 02, 2011
The concept of "Dark Matter" was created to "adjust" our models of gravity when it was noted that suns and galaxies do not move in accordance with our gravity models.

Could have done without the "quotes", but more or less true.

You may consider it scientific to create an imaginary substance to "balance" a flawed model,

Boy, could you possibly have loaded that statement any more? As you've stated it, it's piffle.

but it would make much more sense to try to find out why our models are not working.

Yes, that would be due to the dark matter, since GR is about the most successful and most tested theory in science and because all modified gravity models have fatal flaws.

There are many obvious flaws in the concept of DM

Hardly.

More...
soulman
4.2 / 5 (10) Apr 02, 2011
it cannot be seen, that it cannot be examined in a lab, that it does not interact with the universe at all except through gravity, etc.

Why are these flaws? Hmm, let's see, black holes pretty much fit the same bill. Are you a black hole denier also?

But the flaw which is most obvious and which cannot be denied is that scientists presume that there is always just enough DM in just the right places to account for whatever anomalies are observed.

That's a nonsensical statement. Never mind that dark matter's gravitational effects have been observed through lensing and that without DM in evolutionary models of the universe, we simply don't get a universe that we live in today. Put it all together, and it's pretty compelling.
dogbert
1.8 / 5 (16) Apr 02, 2011
Never mind that dark matter's gravitational effects have been observed through lensing ...


That is just the result of believing in an imaginary substance used to adjust our models to match our observations. See gravitational lensing which does not match our gravity models? Dark matter to the rescue again!

Whenever our gravitation models fail to match our observations, create more dark matter to kludge the observations.

We will continue to find dark matter whenever we see something we don't understand. It is the ideal kludge since it cannot be seen by definition.
bluehigh
1.3 / 5 (13) Apr 02, 2011
So right away, either this article is wrong and ridiculous about the facts, or else the DM theory is instantly shown to be internally inconsistent.


@QC Both. The article is complete tosh and DM theory is no more than desperate speculation.
Moebius
1.5 / 5 (16) Apr 02, 2011
Speculations such as this article are the result of using a kludge to "fix" what we observe gravitationally on stellar scales and then actually believing in our kludge.

If even a fraction of the effort which is spent on "proving" the existence of dark matter went into discovering why gravity does not behave as we expect on stellar scales, we would probably have a much better understanding of gravity.


You science primadonna's who vote down comments like this make me sick. Are you in possession of knowledge that no one else on this planet has? DM is a theory, there is not one single shred of evidence that it exists. There is nothing other than the effects we observe which don't fit OTHER theories. Not only could those theories be wrong, they could be right without dark matter. We are constantly finding new forms of previously unobserved baryonic matter for one thing. All you people who vote down posts questioning the existence of dark matter are just showing your own stupidity
FrankHerbert
1 / 5 (64) Apr 02, 2011
kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge kludge
soulman
3.9 / 5 (14) Apr 02, 2011
That is just the result of believing in an imaginary substance used to adjust our models to match our observations.

No, that is the opposite of belief - it's a result of OBSERVATION.

Whenever our gravitation models fail to match our observations, create more dark matter to kludge the observations.

Are you intentionally obtuse? How come we keep seeing the effects of this 'kludge' you keep banging on about? Is the Bullet Cluster also a kludge? Is the 3-year WMAP data which shows that the universe must have dark matter also a kludge? Is the Hubble COSMOS survey map of half a million gravitationally lensed galaxies (by non-luminous matter) also a kludge?

We will continue to find dark matter whenever we see something we don't understand. It is the ideal kludge since it cannot be seen by definition.

/facepalm.
Why don't you go back to your truly invisible god and pray for some intellectual enlightenment?
Wulfgar
not rated yet Apr 02, 2011
Pyle -

Photons are subject to gravity, so they are not what I was talking about. I was saying that if there is dark matter, then there could also be matter that interacts with our type of matter electromagnetically but not gravitationally. Not saying I believe in either one, though.
ShotmanMaslo
3.9 / 5 (11) Apr 03, 2011
All you people who vote down posts questioning the existence of dark matter are just showing your own stupidity


Nope, lets question everything. I am voting down posts that are calling it a kludge and claiming that it surely does not exist or is unscientific, without any supporting existence. We dont know if dark matter exists, but it seems to be consistent with observations, and is a solid scientific hypothesis. Whether armchair pseudocosmologists agree with it or not is irrelevant.
dogbert
1.8 / 5 (15) Apr 03, 2011
soulman,

No, that is the opposite of belief - it's a result of OBSERVATION.


To quote your comment, "Are you intentionally obtuse?".

If we do not see enough mass to account for the observed gravitation -- which happens everywhere we look outside our solar system -- you believe we should fill wherever we are looking with invisible matter. I think it would make much more sense to try to determine why gravity behaves differently everywhere we look than what our models say it should.

When your model consistently differs from observations, the scientific action is to seek a model which does match the observations.

Deciding that everywhere we look, there is just enough (never too much, never too little and always distributed perfectly) dark matter to account for the observational anomalies is not a very scientific thing to do.
dogbert
1.9 / 5 (15) Apr 03, 2011
ShotmanMaslo ,

I am voting down posts that are calling it a kludge and claiming that it surely does not exist or is unscientific ...


1) It is a kludge.
2) Dark matter may exist. It is far more likely that our models of gravity are inadequate.
3) It is far more scientific, when your model fails, to seek a better model.
ShotmanMaslo
3.4 / 5 (5) Apr 03, 2011
If it's not dark it's visible. Infrared light may not be able to be seen by the human eye, but we can still "see" it.


It is transparent to EM radiation. Therefore we can detect it only by its gravitational effects (thats how it was discovered), and if it is its own antiparticle, we should be able to detect it also by the results of its annihilation.
ShotmanMaslo
3.2 / 5 (9) Apr 03, 2011
ShotmanMaslo ,

I am voting down posts that are calling it a kludge and claiming that it surely does not exist or is unscientific ...


1) It is a kludge.
2) Dark matter may exist. It is far more likely that our models of gravity are inadequate.
3) It is far more scientific, when your model fails, to seek a better model.


Yes, to seek a better model. And one of these better models is one with Dark matter in it. Also, dark matter is not a kludge. It is an elegant and simple solution for the observed discrepancy, requiring nothing more than an another particle. Kludge is an ad-hoc unexplained or overly complicated solution.
ShotmanMaslo
3.2 / 5 (9) Apr 03, 2011
A good analogy is how neutrinos were discovered. There was missing energy detected during particle colisions. There were two options on how to explain it:

1. Simple and elegant one - there is a new particle called neutrino. This is equivalent to dark matter solution for current observed discrepancy.

2. Complicated and inelegant one - our equations on conservation of energy are wrong. This is a kludge solution, represented by current modified gravity models, and it proved to be wrong.

So much for dark matter being a kludge..
Ethelred
4 / 5 (8) Apr 03, 2011
reacts to normal matter via EM mechanisms then it ISN'T all that DARK is it?
That is wrong. Dark matter does not interact via EM it interacts via the Weak Force. Assuming it exists of course.

You can't have your cake and eat it too
YOU changed the interaction not them.

either it only interacts gravitationally and is dark
Wrong. The WEAK force is involved. Photons are generated AFTER there is a Weak force interaction.

Analogy

Two drunken idiots are driving around in the dark with no lights. Then don't interact via EM. BANG they interact via direct impact (Weak force) the resulting conflagration (due to alcohol interacting with metal on silicates) releases copious quantities of photons not to mention audible cursing.

I stand by what I said as long as people are still calling it dark matter
Translation - I will hold my breath till my face turns blue rather than accept the concept of Weakly Interacting Particles because there are no Z or W bosons.

Ethelred
dogbert
1.9 / 5 (14) Apr 03, 2011
A good analogy is how neutrinos were discovered. There was missing energy detected during particle colisions.


There is considerable difference in noting that we have lost some mass/energy during a collision and finding that mass/energy and the action of creating dark matter to normalize models which consistently fail to match observations.

Dark matter is a kludge in that it was invented to fix the anomalies between what is observed and our models of gravity. In all fairness, it could conceivably be a serendipitous kludge, but that is very unlikely.
ShotmanMaslo
3.5 / 5 (11) Apr 03, 2011
Dark matter is a kludge in that it was invented to fix the anomalies between what is observed and our models of gravity. In all fairness, it could conceivably be a serendipitous kludge, but that is very unlikely.


Thats just your opinion, and among actual cosmologists dark matter is regarded as more elegant (and probable) solution than modified gravity models.

Theory of relativity is very well tested and is unlikely to be wrong. On the other hand, discovering another particle is not forbidden by any current knowledge, has happened many times so far, and is even predicted by some particle physics hypotheses.

You may believe that dark matter is a kludge, but modified gravity models are the mother of all kludges, then.
Ethelred
4.1 / 5 (9) Apr 03, 2011
QC and Eth brought up very good points about the HUGE holes in this theory.
Where did I do that? And QC couldn't point out a hole with both hands and a map but I know you CAN read so you must be in one of your stubborn modes again.

It stretches credulity.
So do neutrinos but they do seem to exist anyway. They are Weakly Interacting NON-massive particles. The problem is they do occasionally interact via the Weak Force just as WIMPS are supposed to do as well. So why do the neutrinos show up in the water tanks but not the WIMPS? And could we tell the difference if they did?

Moreover why should dark matter be any different than matter if it was all created in the big bang
Why should leptons and quarks be different? Bosons and baryons?

it would have had virtually zero distance between it and it's anti-dark matter counterpart.
They rarely interact with anything including each other.

Ethelred
dogbert
1.8 / 5 (16) Apr 03, 2011
ShotmanMaslo,
You may believe that dark matter is a kludge, but modified gravity models are the mother of all kludges, then.


Newton's model was based on observations. But then we found that it did not match observation in some instances so:

Einstein's model was based on better observations. But then we observed that neither Newton's nor Einstein's model reflects the observed gravitation on stellar scales so:

It is time to seek another model which does match observation.

Or, we can just continue to assume that there is a lot of invisible mass which pervades the universe and which is always found in just the correct amount and in precisely the right places to account for the gravitation we observe.

The scientific approach is to correct the model (or find a new model) which matches the observations. Then your model will be able to predict -- which is what makes a model useful.

Adding dark matter to each observation solves nothing and allows no prediction. Not useful.
soulman
3.5 / 5 (11) Apr 03, 2011
To quote your comment, "Are you intentionally obtuse?".

Superb comeback. To paraphrase: I know you are, but what am I? Bart Simpson would be proud!

If we do not see enough mass to account for the observed gravitation -- which happens everywhere we look outside our solar system -- you believe we should fill wherever we are looking with invisible matter.

I've just given you FOUR good reasons why this matter exists and why GR remains unchallenged, but no, you simply ignore the evidence. Makes sense I guess - you're a climate change denier also.

When your model consistently differs from observations, the scientific action is to seek a model which does match the observations.

Idiot - that's exactly what DM explains, with much supporting evidence.
soulman
3.2 / 5 (13) Apr 03, 2011
Adding dark matter to each observation solves nothing and allows no prediction. Not useful.

It's ironic that you refuse to accept something for which there is ample evidence but choose to believe in something for which there is absolutely zero evidence and totally unfalsifiable - ie, god. You simply have no credibility.
dogbert
1.8 / 5 (16) Apr 03, 2011
soulman,
... you're a climate change denier also.

Please point to anything I have ever written where I denied climate change. Climate is not static. It is expected to change. I don't support social redistribution through AGW fear mongering, but I expect the world's climate to change.

It's ironic that you refuse to accept something for which there is ample evidence but choose to believe in something for which there is absolutely zero evidence and totally unfalsifiable - ie, god.


Now we get to the crux of your arguments against me. You don't like me because I believe in God.

1) There is lots of evidence for God, but you are certainly welcome to ignore it.
2) There is no evidence for dark matter, but again, you are welcome to believe in it.

This thread, by the way, is not about religion, it is about dark matter. Try to stay on topic.
soulman
3.4 / 5 (14) Apr 03, 2011
I don't support social redistribution through AGW fear mongering, but I expect the world's climate to change.

RightWhingNut commentary = AGW denial, check.

You don't like me because I believe in God.

Yeah, that's a pretty big strike against your critical reasoning faculties. I don't know you as a person in real life, but the views you espouse on this board lead me to believe that I would not be socializing in your circles.

1) There is lots of evidence for God, but you are certainly welcome to ignore it.

Bullshit. Name one.

2) There is no evidence for dark matter, but again, you are welcome to believe in it.

Bullshit again. I've given 4 different pieces of evidence, You have not refuted one, just chose to ignore them. So why don't you do it now for the record? Refute each piece of evidence I posted above. I'd like to know your scientific objections.
soulman
3.3 / 5 (16) Apr 03, 2011
This thread, by the way, is not about religion, it is about dark matter. Try to stay on topic.

I repeat, refute my stated evidence for DM. That fact that you believe in magical sky fairies goes to your lack of credibility in scientific reasoning.

However, if you surprise me with reasonable arguments against my stated pieces of evidence, then I will give you due acknowledgment and re-examine the evidence. Until you do that, you're just in denial.
dogbert
1.7 / 5 (17) Apr 03, 2011
I repeat, refute my stated evidence for DM.


All gravitational anomalies, i.e., gravitation observations which do not match our gravitational models. Observations of gravitation are real, not subject to refutation. Dark matter is made up. Can't prove it is not there because it is invisible and only reacts gravitationally (by definition). It is a perfect kludge because, like God, it cannot be examined scientifically.

So prove that there is no god and I will prove that there is no dark matter.
Deesky
3.5 / 5 (11) Apr 03, 2011
dogbert you are an embarrassment to rational thought.
dogbert
2.1 / 5 (15) Apr 03, 2011
Deesky,
I can't comment on your ability to think rationally since you have not participated in the discussion.

Modernmystic
1.4 / 5 (11) Apr 03, 2011
That is wrong. Dark matter does not interact via EM it interacts via the Weak Force. Assuming it exists of course.


Then why did it take aberrant galactic orbits to "detect" it?
YOU changed the interaction not them.


I'm simply questioning the weak force interaction based on it's discovery. Moreover if it can produce photons via interactions it's NOT dark matter. It's visibly detectable matter and therefore should have been noticed.

...the resulting conflagration...


Should have been detected before Zwicky.

Translation - I will hold my breath till my face turns blue rather than accept the concept of Weakly Interacting Particles because there are no Z or W bosons.


No I'll hold my breath until people start calling a spade a spade. If it produces photons it's simply not dark matter.

soulman
3.5 / 5 (13) Apr 03, 2011
All gravitational anomalies...blah, blah

So, no refutation? I'll make it simple for you. These are the various pieces of evidence that you have to argue against:

1) Explain the dynamics of the Bullet Cluster without DM.
2) Explain the multi-year WMAP data which shows that the universe must have DM.
3) Explain the Hubble COSMOS survey map of 1/2 million gravitationally lensed galaxies without DM.
4) Explain how the universe can evolve (excuse the E word) to look as it does today without DM scaffolding?

It is a perfect kludge because, like God, it cannot be examined scientifically.

Except for the above four observed and theoretical pieces of evidence.

So prove that there is no god and I will prove that there is no dark matter.

/facepalm x 2
Modernmystic
1.3 / 5 (12) Apr 03, 2011
Where did I do that?


Your comment about stars, shouldn't we have noticed stars are burning hotter at the center of the galaxy without this "theory"?

And QC couldn't point out a hole with both hands and a map but...


His point about DM distribution has merit...even if he's usually a tool.

So do neutrinos but they do seem to exist anyway. They are Weakly Interacting NON-massive particles. The problem is they do occasionally interact via the Weak Force just as WIMPS are supposed to do as well.


Where are all the copious amounts of anti-neutrinos in nature then? (see below)

Why should leptons and quarks be different? Bosons and baryons?


THEY are the ones that are suggesting DM and "anti-DM" interact like matter. Therefore the big bang would have taken care of one or the other just the same

They rarely interact with anything including each other.


Then how are they going to generate the amounts of heat they're postulating?
Modernmystic
1.9 / 5 (12) Apr 03, 2011
dogbert, give it up bro. DM most likely exists....just toooo much evidence out there for it that nothing else can properly explain in any kind of self consistent manner.

My problem is the properties they're ascribing to it in this article seem to...no not seem to, but definitely DO contradict their own theory on several levels. I'm just asking for some internal self consistency.
genastropsychicallst
1 / 5 (5) Apr 03, 2011
Going electric to star-empty dark matter is impossible because lighter matter from possible magnetic colder given also not star-full was.

Out of my written sentence in my blog '' biopsychica '', also to be find by Googling '' Albert Marinus '' or at facebook.com/albertstmarinus for the link.
dogbert
1.6 / 5 (13) Apr 03, 2011
My problem is the properties they're ascribing to it seem to contradict their own theory on several levels. I'm just asking for some internal self consistency.


You won't find consistency and they won't likely find dark matter.

All supposed evidence for dark matter is the observed gravitational anomalies. This is circular reasoning.
1) Observe gravitational anomalies.
2) Create the concept of dark matter.
3) See gravitational anomalies, declare that these are evidence of dark matter.

Dark matter may actually be real. Serendipity does happen. Serendipity is not science, however.
TheGhostofOtto1923
2.3 / 5 (3) Apr 03, 2011
Going electric to star-empty dark matter is impossible because lighter matter from possible magnetic colder given also not star-full was.

Out of my written sentence in my blog '' biopsychica '', also to be find by Googling '' Albert Marinus '' or at facebook.com/albertstmarinus for the link.
Haha. Is the rest of your blog composed of gibberish too? What- you're saying I should visit for confirming my reading seeing for blog as such, was? Does lassie think we should call the sheriff? What?
SincerelyTwo
5 / 5 (3) Apr 03, 2011
Dark matter was postulated by Fritz Zwicky in 1934 to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters. Subsequently, other observations have indicated the presence of dark matter in the universe;

http://en.wikiped...evidence

Observational evidence
2.1 Galactic rotation curves
2.2 Velocity dispersions of galaxies
2.3 Galaxy clusters and gravitational lensing
2.4 Cosmic microwave background
2.5 Sky Surveys and Baryon Acoustic Oscillations
2.6 Type Ia supernovae distance measurements
2.7 Lyman-alpha forest
2.8 Structure formation

It even comes off as very natural, look at all the symmetry everywhere in nature, you really think it stops with what you can see? It's even starting to look like dark matter and dark energy arise naturally out of quantum mechanics.

It's almost very obvious when you really take the time to understand the evidence, the reasoning, the logic, when you put the picture together.
ShotmanMaslo
3.9 / 5 (7) Apr 03, 2011
All supposed evidence for dark matter is the observed gravitational anomalies. This is circular reasoning.
1) Observe gravitational anomalies.
2) Create the concept of dark matter.
3) See gravitational anomalies, declare that these are evidence of dark matter.


Dark matter model does make predictions, it is not just a kludge that can be added at will, like you seem to believe. The results of various types of dark matter or modified gravity models can be tested by simulations. Not to mention that dark matter itself could be detectable.

I repeat, dark matter model is a solid scientific hypothesis, accepted as such by actual cosmologists. You are only embarassing yourself on this forum by calling it a kludge or non-scientific model. There is no reason why dark matter model should be any less probable than modified gravity ones, quite the contrary, new particle is a simpler and more elegant solution (and thus more probable) than new gravity.
ShotmanMaslo
3.7 / 5 (6) Apr 03, 2011
No I'll hold my breath until people start calling a spade a spade. If it produces photons it's simply not dark matter.


Semantics. Dark matter is in fact, transparent, and it may even produce photons when annihilating. Its just a name.
CyberRat
1 / 5 (7) Apr 03, 2011
Dark Matter and energy is a fairytale to correct the accelerated expansion of the universe, seen by redshift. Someday they will find that the universe isn't expanding at all, for now it fits nicely with the bible and about creation. Some (80%) still don't want to accept that the bible is a fairytale as well.
CyberRat
1 / 5 (1) Apr 03, 2011
Here is an interesting article about DM
http://www.econom...=2404626
Modernmystic
1.4 / 5 (10) Apr 03, 2011
Semantics. Dark matter is in fact, transparent, and it may even produce photons when annihilating. Its just a name.


No it's not just semantics. If it weren't then we'd have been able to detect it without something huge like noticing the anomalies in galactic orbits...

If it produces photons when annihilating and it makes up a quarter of the mass of the universe...we haven't noticed it until just now? Uh ok...

That's me being incredulous.
soulman
3.9 / 5 (7) Apr 03, 2011
Here is an interesting article about DM
http://www.econom...=2404626

A lot has happened since 2003 in cosmology. The article is interesting more as a historical summary of the matter at the time, then as accurate contemporary knowledge.
soulman
4 / 5 (8) Apr 03, 2011
If it produces photons when annihilating and it makes up a quarter of the mass of the universe...we haven't noticed it until just now? Uh ok...

That's me being incredulous.

No, not really. WIMPs are just one candidate for dark matter, there are others - we obviously don't know exactly what they are, so you have to work with various models and predicted energy ranges and eliminate those whose ranges have been tested with no signature found.

One thing to note here is that gamma rays are very hard to detect. We do have detectors which detect extremely large sources of very energetic emissions, but WIMPs are Weakly Interacting, so the concentration of emissions and their energy levels would probably not be detectable with the sensitivity of current instruments.

You can work backwards and ask what can we detect with current tech and would that fit in with any of the proposed DM candidates? If so, you might have a shot of confirming that particular model, but not others.
Ethelred
3.5 / 5 (11) Apr 04, 2011
All gravitational anomalies, i.e., gravitation observations which do not match our gravitational models.
They do match if you add in dark matter. So you can't use that claim to avoid dark matter.

Observations of gravitation are real, not subject to refutation.
Yes and no. They are real but some observations are subject to refutation via BETTER observations. The observations support Dark Matter with GR. No one has an alternative that works better.

Dark matter is made up.
So were neutrinos.

Can't prove it is not there because it is invisible and only reacts gravitationally (by definition).
False. It is supposed to interact via the weak force. I am still waiting to see any interaction. Till then its an interesting hypothesis that deserves consideration.

More
Ethelred
3.5 / 5 (8) Apr 04, 2011
It is a perfect kludge because, like God, it cannot be examined scientifically.
Wrong. Some gods can be examined scientifically and so far they all fail. This hypothesis is still in need of a method of detection by something other than gravity. This should be possible but no one knows how yet.

So prove that there is no god and I will prove that there is no dark matter.
Define your god and then we can have a go at it. You seem to believe in the Abrahamic god and that one is disprovable as it has a Flood that never happened. And you can't disprove dark matter with present information unless you know something no else does.

Ethelred
dogbert
1.3 / 5 (15) Apr 04, 2011
...you can't disprove dark matter with present information unless you know something no else does.


Never said I could. Since we define dark matter as something which we cannot cannot see or examine in any known way, it constitutes a very good kludge.

There also remains the remote possibility that something on the order of dark matter actually exists.
soulman
4.3 / 5 (11) Apr 04, 2011
Since we define dark matter as something which we cannot cannot see or examine in any known way, it constitutes a very good kludge.

Hey dog, a quote comes to mind:

"Hear now this, O foolish people, and without understanding; which have eyes, and see not; which have ears, and hear not"

SincerelyTwo has kindly provided you with 8, that's right, eight(!), ways in which DM has already been examined by the scientific community (you know, the people that do this professionally) and has provided a useful link. Look it up. I'm baffled why you're so pathologically in denial. How does DM interfere with your god?
dogbert
1.3 / 5 (15) Apr 04, 2011
soulman,
...8, that's right, eight(!), ways in which DM has already been examined by the scientific community...


OK. Since dark matter has been examined so thoroughly, please tell all of us all about its characteristics. Is it a single particle? What is its mass? Just fill us in on all its characteristics. Describing it in terms more descriptive than "you can't see it" will make discussing it so much more fun.
soulman
3.8 / 5 (10) Apr 04, 2011
OK. Since dark matter has been examined so thoroughly, please tell all of us all about its characteristics. Is it a single particle? What is its mass? Just fill us in on all its characteristics.

Sheesh. Read the frigging link! You can lead a horse to water...
Jayded
1 / 5 (3) Apr 04, 2011
You guys are such woman. Resemblant to the conjecture against the earth being round.
Everything starts with a theory.
Ethelred
3.3 / 5 (7) Apr 04, 2011
Then why did it take aberrant galactic orbits to "detect" it?
Why did it take tons of water to detect neutrinos? Same reason. The weak force is WEAK.

I'm simply questioning the weak force interaction based on it's discovery
No you ignored it and brought up EM which is related to the Weak Force but much stronger. Since the gravitational evidence implies that WIMPS would much colder than neutrinos they should be packing much lower energy thus making them harder to detect.

if it can produce photons via interactions it's NOT dark matter
That is just an attempt to argue by definitions in field that is not beholden to definitions. In other words Dark Matter is called that because it does NOT emit EM. Nor did do neutrinos produce photons. The matter the neutrinos bang into produce the photons.

It's visibly detectable matter and therefore should have been noticed
False. It isn't visible because it only interacts with the weak force EXCEPT in just like neutrinos

More
Ethelred
2.3 / 5 (3) Apr 04, 2011
Should have been detected before Zwicky.
Why? Again, the interactions are via the weak force and apparently they don't have much kinetic energy per particle.

No I'll hold my breath until people start calling a spade a spade.
No we aren't going to use your definition. You come up with an idea and THEN you get to define the words, within the limits of the theory.

If it produces photons it's simply not dark matter.
Where the hell do you seem them doing that? Do you have magic eyes?

Clearly you did NOT read the same article.

When two WIMPs come together, they work to annihilate each other and cause a burst of energy.
This is their idea and not the standard Dark Matter hypothesis.

From the PAPER not the article
If the dark matter can annihilate into standard model particles with a roughly weak-scale cross section, capture rates this large will easily lead to capture-annihilation


More
Ethelred
3.4 / 5 (5) Apr 04, 2011
Note the 'standard model particles' not photons. The photons in you posts are all yours.

shouldn't we have noticed stars are burning hotter at the center of the galaxy without this "theory"?
Depends on how much hotter. I am assuming that there is no obvious evidence. The hard part is not knowing the temperature. It is knowing the mass of the stars AND the temperature at the same time. The stars at the center of our galaxy are obscured by nebula limiting observation to radio and infrared. A few hundered degrees is all that is needed for a planet to have liquid water. Stars should have a higher increase in temperature but the paper is about planets and I don't see a calculation for the temperature differential of stars.

On top of which they made a number of assumptions about the planets. They were using planets with greater greenhouse effects than the Earth has but not as much as Venus. I don't think main-sequence stars have greenhous effects.

More
Ethelred
2.6 / 5 (5) Apr 04, 2011
I had an idea for a way to test the hypothesis. I don't know if it is feasable and the Universe may not allow the authors assumptions to come true which would make their idea fail even if Dark Matter exitst and interacts to a small degree.

The speed of the Dark Matter in the paper is fairly low. 10-20 km/s which is far lower than the neutrinos that are detected. I suspect the velocity is constrained partly by there not being detected in the neutrino detecors as well as by the apparent distribution of Dark Matter shown by gravitational lensing.

His point about DM distribution has merit...even if he's usually a tool.
He has decided that a solid disc is the correct model and won't listen to anyone that points out that DM is a closer fit to a sphere. He would have a point if he wasn't completely wrong.

More
Ethelred
2.6 / 5 (5) Apr 04, 2011
Where are all the copious amounts of anti-neutrinos in nature then?
All over the Universe failing to interact with pretty much anything. And there is a strong possibility that, like photons, neutrinos are their own anti-neutrino. And Oliver hates the idea which is another thing going for it.

THEY are the ones that are suggesting DM and "anti-DM" interact like matter.
No. Not quite. They are suggesting that they interact with each other like they do with matter. Hardly ever. The key is the idea that WIMPS collect in planets by losing momentum in rare interactions with baryonic matter. This increases the density of the WIMPS to the point that interaction with each themselves is much more likely.

More
Ethelred
2.6 / 5 (5) Apr 04, 2011
Therefore the big bang would have taken care of one or the other just the same
Which is very different from WIMPS collecting over long periods of time in planets. WIMPS rarely interact so, even at the densities of the BB, there would be little interaction in the short time they were at high density. VERY early in the BB there wouldn't be any WIMPS or baryons.

Then how are they going to generate the amounts of heat they're postulating?
Ocassional captures of WIMPS by the planets. Lots of WIMPS so it adds up over time till the rate of destruction matchs the rate of capture. That is from the actual paper. The link is at the bottome of the article. Am I the only one that read it?

Of course I didn't read it till I started this reply. Some of the questions are answered there. The whole thing is pretty speculative.

Ethelred
Modernmystic
1 / 5 (3) Apr 04, 2011
Why did it take tons of water to detect neutrinos? Same reason. The weak force is WEAK.

But if interactions produce heat we can see that. We don't have to infer it from aberrant galactic orbits LISTEN to what I'm saying.
No you ignored it and brought up EM which is related to the Weak Force but much stronger. Since the gravitational evidence implies that WIMPS would much colder than neutrinos they should be packing much lower energy thus making them harder to detect.

If they produce gamma rays when they interact with their anti-matter counterparts they're not going to be difficult to detect. We've been detecting gamma rays for a long time now
That is just an attempt to argue by definitions in field that is not beholden to definitions.

That's a weak deflection. If we cant have definitions why bother having the field? Why not grunt and click at each other like apes and point upwards every two minutes or so?

cont
Modernmystic
1 / 5 (4) Apr 04, 2011
In other words Dark Matter is called that because it does NOT emit EM.

It does if it interacts with anti-DM. Go fish.
Nor did do neutrinos produce photons. The matter the neutrinos bang into produce the photons.

Non-sequitir. Its still detectable by the EM it emits by interactions with other particles or other kinds of DM. Thanks for proving my point.
False. It isn't visible because it only interacts with the weak force EXCEPT in just like neutrinos


True, but since it is visible via EM emissions its detectable PERIOD. It doesnt matter if it reflects EM all the time or only when it hits another particle the EM evidence is STILL THERE.

Modernmystic
1 / 5 (3) Apr 04, 2011
Why? Again, the interactions are via the weak force and apparently they don't have much kinetic energy per particle.


So DM/anti-DM annihilations don't produce a lot of energy? Where is all this supposed heating coming from in the article then? Or are you being intentionally obtuse by pointing out the weaker of the two interactions in order to stretch your point?

No we aren't going to use your definition. You come up with an idea and THEN you get to define the words, within the limits of the theory.

They aren't defining the word within the limits of their theory, why are the rules different for them?
Where the hell do you seem them doing that? Do you have magic eyes?

The PAPER says they're producing gamma rays!! You DO know that gamma rays are simply very energetic photons neh???

(more)
Modernmystic
1 / 5 (3) Apr 04, 2011
Depends on how much hotter.


Fair enough. But if it were hot enough to heat a planet without a star, my guess is we'd have noticed a difference in the stars

All over the Universe failing to interact with pretty much anything.


If they're failing to interact how do you know they're there?

And there is a strong possibility that, like photons, neutrinos are their own anti-neutrino. And Oliver hates the idea which is another thing going for it.


Fair point.

No. Not quite. They are suggesting that they interact with each other like they do with matter. Hardly ever.


Again then where is all this heat going to come from? And if high densities produce more interactions (which they would) then Ill refer back to my original point about the big bang and why wasn't nearly all the anti-dark matter taken care of then? Things were pretty dense then

(more)
Modernmystic
1 / 5 (3) Apr 04, 2011
last one:

Which is very different from WIMPS collecting over long periods of time in planets.


Indeed it is, there should have been virtual annihilation at big bang densities because they were ALL there and they were in a space MUCH smaller than a planet. There would have be a HELL of a lot of interaction no matter how rarely they do so now.
Pyle
2.5 / 5 (8) Apr 04, 2011
Wow! I guessed I missed a lot being away from my computer all weekend.
Ethelred and soulman: good on ya!
Modernmystic and dogbert: do you guys just like to argue the losing side every time?

Well, here we go! I'll start with the earliest random points and then hit Mm's most recent evasion to Eth.

Ethelred suggested a way to test this theory by looking for hotter stars at the center of galaxies. That would be great if we had a means to compare stars that didn't involve their spectra and perceived heat. How would we determine that two stars were the same enough to know whether one was hotter or not? Interesting idea, but I don't think it would be that easy.

QC: Yes, distribution of DM is typically thought of outside the galaxy and contributing to the rotational curves, but that doesn't mean there wouldn't be a greater density of DM trapped in the center of galaxies. DM in the suspected halos would be VERY sparse and still contribute the gravity effects we observe.

More...
Pyle
2.6 / 5 (9) Apr 04, 2011
My biggest problem with DM is that it contributes these huge gravitational effects, yet doesn't seem to gather the same ways baryonic matter does into stars and planets. What gives, I am attracted to you, but not that much? My inability to reconcile this is why I started chasing Moffat's MOG when I heard more about it. Anyway...

On to Mm...
Why did it take tons of water to detect neutrinos? Same reason. The weak force is WEAK.

But if interactions produce heat we can see that. We don't have to infer it from aberrant galactic orbits LISTEN to what I'm saying.
No, the fault is not Eth's listening. You need to read more and talk less. Where are the proposed DM interactions that produce heat hypothesized to take place? Not in a pool of water like neutrinos. The proposed method of heating planets in the paper involves conditions we can't replicate or even observe, and again, I find fantastical. (But not without merit.)

More...
Modernmystic
1 / 5 (7) Apr 04, 2011
No, the fault is not Eth's listening. You need to read more and talk less.


I don't give a flying F about neutrino interactions. OK, are you listening. I'll say it one more time.

I don't CARE about neutrino interactions. I'm not disputing these interactions take place, I'm not disputing those interactions are WEAK. DO YOU U N D E R S T A N D? Those interactions are totally completely and UTTERLY IRRELEVANT to the point I'm trying to make and neither of you are getting that. I F***ING AGREE WITH YOU!!!

My problem is EXACTLY where I said it was, not in a pool of water two miles underground. *LISTEN*!

Good God.
Pyle
3 / 5 (10) Apr 04, 2011
If they produce gamma rays when they interact with their anti-matter counterparts they're not going to be difficult to detect.
Yeah they are if they only do so very infrequently or when trapped in the center of another huge mass. The density of DM in space is hypothesized to be low. Any reactions would be infrequent and more importantly would NOT affect other DM particles (i.e. no chain reaction). How could you possibly tell if a stray photon came from DM annihilation or some other source? Maybe if they come up with some characteristic of the output of the proposed reaction we could look for it.

...definitions...
DM is dark because it isn't directly observed, not because it doesn't react. The only reason we guess it might be there is because we observe its effects. We don't see the effects of neutrinos unless we bury a pool of water and surround it with light detectors. They are WEAKLY interacting. I don't really see how to fix your ill-logic here.

More...
Modernmystic
1 / 5 (4) Apr 04, 2011
Yeah they are if they only do so very infrequently or when trapped in the center of another huge mass. The density of DM in space is hypothesized to be low.


Not acccording to these guys, it can heat a planet. Try again.

How could you possibly tell if a stray photon came from DM annihilation or some other source?


If what we SEE is over what we'd expect the gamma level to be then yeah we can make some inferences. ARE WE SEEING THAT? If not then...you figure it out.

DM is dark because it isn't directly observed, not because it doesn't react.


If it's reactions produce EM radiation it isn't dark and it's presence can be observed in the EM spectrum. I really can't help you here.
Pyle
2.7 / 5 (9) Apr 04, 2011
I'm going to skip the circles around the misunderstanding regarding DM's ability to be observed via its interactions. We see its effects, go up to soulman and SincerlyTwo's comments. The direct interactions that would create EM would be near impossible to detect with current technology given their infrequency and necessary conditions.

Indeed it is, there should have been virtual annihilation at big bang densities because they were ALL there and they were in a space MUCH smaller than a planet.

Why virtual? Why couldn't there have been annihilations at BB? I haven't seen any reason why there couldn't have been, have you? Most BB theories wouldn't exclude these reactions.

DM is based on solid math and science to explain our astronomical observations. Is it a plug? Yes, but so was Neptune. Could it end up like the planet Vulcan instead, I hope so, but the jury is still out. (Paraphrased from Moffat's "Reinventing Gravity". My pet beyond the SM theory of 2011.)
Pyle
2.5 / 5 (8) Apr 04, 2011
Not acccording to these guys, it can heat a planet. Try again.

Where can it heat a planet? huh? Oh yeah, in the center of a galaxy, where we can't observe it.

If what we SEE is over what we'd expect the gamma level to be then yeah we can make some inferences. ARE WE SEEING THAT? If not then...you figure it out.
And what exactly is the expected gamma level? Maybe we are SEEING stray gammas from DM annihilations, but we have no way of distinguishing them currently.

Our planet may be heated a couple degrees by DM interactions. We don't really know. How would we know?
Pyle
3 / 5 (10) Apr 04, 2011
Wow! I missed your first interruption of my comments, Mm. I said you need to read more, you blew up, demonstrating that you failed to read and consider the very next sentence I wrote. You are obviously not a very rational person, but this is fun so...

Those interactions are totally completely and UTTERLY IRRELEVANT to the point I'm trying to make and neither of you are getting that.

No they aren't irrevlevant. They are WIP's, the theory is assuming DM is WIMP's. Again, neutrinos are Weakly Interacting Particles. DM is the same only Massive. The existence of neutrinos and our difficulty observing them indirectly supports that there could be a DM particle that is massive that we would have difficulty observing. Not irrelevant.
Modernmystic
1 / 5 (6) Apr 04, 2011
Not irrelevant.


Completely irrelevant because the interaction postulated in the article is NOT the same kind of interaction...mmmmkay.

You are obviously not a very rational person


No, I'm just not patient with stupid people..
ShotmanMaslo
3.7 / 5 (6) Apr 04, 2011
Modernmystic

You are making lots of unsupported guesses, cosmology and particle physics is not a field where shooting from the hip about what things should do is reliable.

Dark matter annihilating into gamma rays does not necessarily mean that we will readily see this effect in the sky. It may require painstaking search, or even be so weak to be under our current detection capabilities. The same applies for heat deposited by this annihilation in stars.

All that while being able to heat a planet in galactic center.

Pyle
2.5 / 5 (8) Apr 04, 2011
Completely irrelevant because the interaction postulated in the article is NOT the same kind of interaction...mmmmkay.
Hmmm. Can't argue with that, because it doesn't make sense. Did you even read what I wrote? Are you even having the same conversation as the rest of us. In most comment streams it seems you have decent arguments, usually wrong, but at least you seem to be paying attention. However, every once in a while you back down into a quote mining troll, taking things out of context and conducting yourself like a jerk. This would be one of those times.

No, I'm just not patient with stupid people.
And which one of us monkeys is arguing against the writers of a peer reviewed research paper, not to mention a majority of astrophysicists? Funny you should be calling us stupid.
Modernmystic
1 / 5 (3) Apr 04, 2011
Can't argue with that, because it doesn't make sense. Did you even read what I wrote?


Did YOU? The interactions they're talking about in the article are about anti-particles. That is NOT a weak interaction. It's a pretty strong one.

So yes or no, is particle anti-particle interaction a WEAK interaction or would you characterize it otherwise?

And which one of us monkeys is arguing against the writers of a peer reviewed research paper, not to mention a majority of astrophysicists? Funny you should be calling us stupid.


http://en.wikiped...uthority
Modernmystic
1 / 5 (6) Apr 04, 2011
You are making lots of unsupported guesses, cosmology and particle physics is not a field where shooting from the hip about what things should do is reliable.


I am indeed, but I don't think any more than the authors of this article. I think it's a pretty good guess that most of any anti-dark matter in the universe would have been taken out during the initial phase of the big bang...no matter how weakly they interact.

Dark matter annihilating into gamma rays does not necessarily mean that we will readily see this effect in the sky. It may require painstaking search, or even be so weak to be under our current detection capabilities.


Indeed it may, THANK YOU for the FIRST reasonable response to anything I've said on this thread. You are absolutely correct, then again it may not be. If what you say is true we can't test the theory so all that I've said in the comments in response to the article is just as valid as anything postulated in the article.

eachus
5 / 5 (3) Apr 04, 2011
I don't know why I bother, but a few things I haven't seen mentioned here...

One of the candidates for CDM (cold dark matter) is "sterile" neutrinos. I think it is easier to tweak some of the parameters of the current neutrino model than to add a fourth flavor. Currently we are at the point where second-order effects, like the temperature of neutrinos when they decoupled from ordinary matter as the universe cooled would leave them hotter than they are now--unless interactions of neutrinos of different flavors can result in photon emission. (It is believed that a neutrino and an antineutrino of the same flavor can annihilate, producing a photon. But that has never been observed, and the neutrino background of the universe is expected to consist of mostly antineutrinos, with very few neutrinos anyway.)

So there is an experiment for you. Create a neutrino beam of any flavor (but not antineutrinos), aim it through a very pure vacuum, and determine the annihilation cross-section.
Pyle
2.4 / 5 (8) Apr 04, 2011
Did YOU? The interactions they're talking about in the article are about anti-particles. That is NOT a weak interaction. It's a pretty strong one.

So yes or no, is particle anti-particle interaction a WEAK interaction or would you characterize it otherwise?

It is funny. You twist and turn every which way to avoid the point being made by people you are debating.
I don't think anybody here has said that DM annihilation would be a "WEAK interaction". The proposed particles are weakly interacting. They interact via the weak force and gravity. They don't interact with EM or the strong force, making them 'dark' and difficult to detect. Not interacting with EM is different from not having interactions that produce EM.

Way to go on the Argument from Authority. Hope that works well for you.
Pyle
1.7 / 5 (6) Apr 04, 2011
You are making lots of unsupported guesses
I am indeed
Thank you for that. What's more is you don't seem to understand any of the science behind your negativity. You seem to be arguing just to argue as of about 20 posts ago.

THANK YOU for the FIRST reasonable response to anything I've said on this thread
Go back and read my comments a little more carefully. ShotmanMaslo thank you for getting it into Mm's dense skull.
To put this all in perspective, who said this:
I think, the paper is based on unverified properties of dark matter. In particular, their assumptions regarding DM anti-DM annihilation seems to rest on very shaky ground.

Oh wait, I did before you even opened your pie hole. If you read this and think to yourself, "Then what was he arguing about then?", you need to go back and review the conversation.
Pyle
1.7 / 5 (6) Apr 04, 2011
@eachus: Good try. The reason nobody has talked about "sterile" neutrinos or the different neutrino flavors is that nobody would understand it. That level of technical details sails right over the heads of most everyone here. I mentioned LHC I think, but nobody mentioned KATRIN. Anyway...

Create a neutrino beam of any flavor (but not antineutrinos), aim it through a very pure vacuum, and determine the annihilation cross-section.
Sounds expensive. Since we have already run neutrino beam experiments and didn't notice anomalous energy emissions, my guess is this would be a beam held over a large volume of vacuum with a huge detector run for a long time period. Sorry, sounds REALLY expensive.
ShotmanMaslo
3.7 / 5 (6) Apr 04, 2011
I am indeed, but I don't think any more than the authors of this article. I think it's a pretty good guess that most of any anti-dark matter in the universe would have been taken out during the initial phase of the big bang...no matter how weakly they interact.


Here it is again, comparing you wild guess to a scientific study. Authors of this article do have math to support their assertion, while your guess is not supported by anything more than an amateur opinion about very complex subject. Thanks for proving my point.

continued
ShotmanMaslo
3.2 / 5 (5) Apr 04, 2011
Indeed it may, THANK YOU for the FIRST reasonable response to anything I've said on this thread. You are absolutely correct, then again it may not be. If what you say is true we can't test the theory so all that I've said in the comments in response to the article is just as valid as anything postulated in the article.


String theory or black holes cannot be tested by our current capabilities, too. It does not make them just as valid as ramblings of a pseudocosmologist on an internet forum, tough. You are not making any sense.
FTL4Life
1.6 / 5 (7) Apr 04, 2011
There are so many other (and to me) more plausable explanations for all this lensing that we do not need dark matter. A star's own eat, dust, other unknown obstructions, dataloss, ect. Why is it more likley that there's this virtually undetectable substance instead of us just not being able to see into space as well as we think?
SincerelyTwo
3.9 / 5 (7) Apr 04, 2011
There are so many other (and to me) more plausable explanations for all this lensing that we do not need dark matter. A star's own eat, dust, other unknown obstructions, dataloss, ect. Why is it more likley that there's this virtually undetectable substance instead of us just not being able to see into space as well as we think?


You haven't done enough reading, and you've only addressed -one- of the phenomena that needs to be explained, not to mention you're wrong anyway, all of that is accounted for and then some. More importantly Dark Matter wasn't 'invented' to explain lensing, it does however explain it. Read my previous post. Even more important than all of that; you are obviously not even close to educated on the topic due to asking the question in the first place, so it should have been obvious to you how naive your comment was from that alone.

Where'd all of the trolls come from? This site used to be dominated by a pretty decently educated niche community. Lame.
soulman
3.5 / 5 (8) Apr 04, 2011
@Pyle
My biggest problem with DM is that it contributes these huge gravitational effects, yet doesn't seem to gather the same ways baryonic matter does into stars and planets. What gives, I am attracted to you, but not that much? My inability to reconcile this is why I started chasing Moffat's MOG when I heard more about it.

That's explained by virtue of the fact that DM only interacts gravitationally (in most front-running models). For baryonic systems that undergo gravitational collapse (stars, planets, etc) you need a mechanism for getting rid of angular momentum of the material that is collapsing, otherwise it will keep going.

DM isn't influenced by any of these mechanisms, such as radiation and viscous interactions or drag, which would transport angular momentum radially outwards in a collapsing system. That's why you won't get a cloud of DM particles to collapse into a dense body.
Pyle
1 / 5 (2) Apr 04, 2011
@soulman: Sorry, I was being simple.
Just using gravity I think you can conjure up methods to create DM densities that would create a Swartzchild radius large enough to create DM black holes. Even without going that far I would think clumps would be created that should be discernible. The observed filaments show us, I think, that DM does "clump". I just haven't been satisfied with (or couldn't understand) any ideas about what limits the "clumpiness". Granted baryonic matter undergoes reactions to create EM we observe, but there is five times more DM in the universe and it makes me very skeptical when we look deeper and deeper without seeing evidence of more dense and/or local DM structures.

Ultimately what I need is another book written for near illiterates so that I can understand better. Somebody ping me when Dark Matter for Dummies comes out.
soulman
4 / 5 (8) Apr 05, 2011
Just using gravity I think you can conjure up methods to create DM densities that would create a Swartzchild radius large enough to create DM black holes

No, you can't, for exactly the reason I described in my previous post. You can get loose aggregations on large scales, such as galaxies and galaxy clusters, but they cannot coalesce into dense clumps like planets or stars. This is because they cannot lose their angular momentum due to them only interacting gravitationally, so they just keep on moving, not coalescing. I'm pretty sure that this is the answer to your question (if I'm reading it correctly).

PaulieMac
3.7 / 5 (3) Apr 05, 2011
Somebody ping me when Dark Matter for Dummies comes out.


www.dummies.com/h...rgy.html

:)
Modernmystic
1 / 5 (5) Apr 05, 2011
That's explained by virtue of the fact that DM only interacts gravitationally (in most front-running models).


LMFAO. Ironic...
Shelgeyr
1 / 5 (5) Apr 05, 2011
"The pitter-patter of dancing unicorn hooves could provide heat for starless planets"

There! Fixed it for ya!
ubavontuba
1.3 / 5 (13) Apr 05, 2011
@dogbert:

Deesky,
I can't comment on your ability to think rationally since you have not participated in the discussion.
Deesky and Soulman are one and the same. Soulman uses Deesky to downrank anyone he doesn't like and uprank himself.

It's pretty sad when an individual needs this much self-reinforcement. I guess he has no real friends, so he has to make them up for himself.
Modernmystic
1.6 / 5 (13) Apr 05, 2011
@dogbert:

Deesky,
I can't comment on your ability to think rationally since you have not participated in the discussion.
Deesky and Soulman are one and the same. Soulman uses Deesky to downrank anyone he doesn't like and uprank himself.

It's pretty sad when an individual needs this much self-reinforcement. I guess he has no real friends, so he has to make them up for himself.


I wondered about that. I knew Deesky was a sock puppet, but didn't know it was soulman. Figures though.
Skeptic_Heretic
3.7 / 5 (3) Apr 05, 2011
Deesky and Soulman are one and the same. Soulman uses Deesky to downrank anyone he doesn't like and uprank himself.

Doubtful, Deesky seems to like my commentary, while soulman cares not for it typically.
ubavontuba
1.7 / 5 (12) Apr 05, 2011
Deesky and Soulman are one and the same. Soulman uses Deesky to downrank anyone he doesn't like and uprank himself.

Doubtful, Deesky seems to like my commentary, while soulman cares not for it typically.
Oh, they're one and the same alright. I caught him red-handed in a transitory flub once.

He's been playing the two accounts differently, thinking he's being sneaky, I guess. But I've known for a long time.

Ethelred
3 / 5 (6) Apr 06, 2011
The reason nobody has talked about "sterile" neutrinos or the different neutrino flavors is that nobody would understand it. That level of technical details sails right over the heads of most everyone here.
I have read the discussions on neutrino masses on Wikipedia. The discussion pages go into far more detail than the article. And even skipping over the math, there might not have been much, it was more than a tad hard to follow, at all. It seemed that few people understood the thinking involved in the whole world. Like reading about infinities a little of that goes along way and far more people have a clue about infinities than the details of neutrinos.

Ethelred
Ethelred
3.3 / 5 (7) Apr 06, 2011
But if interactions produce heat we can see that. We don't have to infer it from aberrant galactic orbits LISTEN to what I'm saying.
I did. Listen to what I am saying. There is no EM involved until AFTER the WIMPS interact and produce baryonic matter.

And yes that is about as speculative as it gets. The only going for it is that doesn't actually violate any known laws. The Invisible Giant Orbiting Aardvark doesn't violate any known laws either. As long as it just orbits that is.

If they produce gamma rays when they interact
Where did you get that? It isn't in the article or the paper.

We've been detecting gamma rays for a long time now
Yes but they aren't involved in this paper. And if the WIMPS are their own antiparticles they won't annihilate each other as this article is having them do.

That's a weak deflection. If we cant have definitions why bother having the field?
The hell its weak. You can't make the universe conform to your definition.

More
Ethelred
2.3 / 5 (6) Apr 06, 2011
It does if it interacts with anti-DM. Go fish.
So you know all about something that has not definite characteristics on a per particle basis? Read the paper. It does NOT have interacting WIMPS producing EM.

Non-sequitir. Its still detectable by the EM it emits by interactions with other particles or other kinds of DM.
Oh horseshit. We are talking about DM. The interactions that produce the EM comes from things that are NOT DM. We can detect baryonic matter just fine. We can't detect neutrinos at all. We CAN detect the photons the baryonic matter produces after interacting with neutrinos. Neutrinos ARE DM. Just not enough mass and too fast to match the DM involved in galaxy formation.

Thanks for proving my point.
I did no such thing.

True, but since it is visible via EM emissions its detectable PERIOD
False. The emissions come from baryonic matter.

More
Ethelred
2.3 / 5 (6) Apr 06, 2011
It doesnt matter if it reflects EM all the time or only when it hits another particle the EM evidence is STILL THERE.
It is NEVER there. It is from the baryonic matter just like with neutrinos which are DM but still baryonic.

So DM/anti-DM annihilations don't produce a lot of energy?
Not in the form of EM in this paper. It is in the form of baryonic matter. Read the bloody paper.

Where is all this supposed heating coming from in the article then?
From the baryons that are produced in the collisions. Its based on someone else's ideas for WIMPS and not that of the authors.

Or are you being intentionally obtuse
No. I am not the one being obtuse. I have had no trouble understanding what you said. I have had no reason to agree with it. After all you have making up even more than the authors of the paper did.

And I am not about to agree with them either.

More
Ethelred
2.3 / 5 (6) Apr 06, 2011
They aren't defining the word within the limits of their theory, why are the rules different for them?
For one they are using OTHER peoples work and ideas as well as their own. For another it is THEIR paper I am discussing.

The PAPER says they're producing gamma rays!!
Where? It is NOT in the paper as far as I can see. And I converted it to text so I could run a FIND command on it since I never saw that when I read it the first time.

You DO know that gamma rays are simply very energetic photons neh???
Yes. Since I was in elementary school. Maybe the EM part was later but I sure remember them from all that nuclear scare crap. The silly films most of you guys see as jokes were rather scary in the 2nd grade.

So could you back up that claim with a quote from the paper. I simply don't see the word gamma used at all.

More
Ethelred
3.3 / 5 (7) Apr 06, 2011
Fair enough. But if it were hot enough to heat a planet without a star, my guess is we'd have noticed a difference in the stars
Read the paper. Its a few hundred degrees at the center of the galaxy. The center of the galaxy is obscured by clouds as I already pointed out. The range of error in temperature vs mass could easily be much higher than a few hundred degrees. And that is assuming that anyone has tried to determine those things. And ignoring that the the authors included greenhouse gasses that really don't apply with suns.

If they're failing to interact how do you know they're there?
Speaking of being obtuse. GRAVITY. Remember. And since we don't really know the details of what makes up the DM gravity is about all we have to go on.

Again then where is all this heat going to come from?
It adds up. Rare interactions involving a LOT of material results in a lot of interactions.

More
Ethelred
3 / 5 (4) Apr 06, 2011
why wasn't nearly all the anti-dark matter taken care of then?
Time vs density. Lots of time and higher than normal density is involved in the article. VERY little time despite the high density is involved with the BB. Most of the baryonic matter is supposed to have been converted to energy. Yet some is left and it interacts a lot more often then the WIMPS are supposed to. So there should be a lot more WIMPS than baryons. Which is what the gravity effects are telling us. And of course a similar CP violation that was involved in baryonic matter could be involved with WIMPS only there really should be a much lower percentage of WIMPS interacting in the first place unless they formed significantly earlier than quarks.

More
Ethelred
2.6 / 5 (5) Apr 06, 2011
here should have been virtual annihilation at big bang densities because they were ALL there and they were in a space MUCH smaller than a planet.
Sure about that? Early on there was NO matter of any kind. I suppose that WIMPS could have formed earlier than quarks and leptons because they are supposed to be heavy but not necessarily heavier than quarks. If they mass less than quarks they would have formed later and thus at lower densities.

Ethelred
Modernmystic
1.4 / 5 (9) Apr 06, 2011
FTA:

When two WIMPs come together, they work to annihilate each other and cause a burst of energy.


Particle anti-particle collisions produce gamma rays. It was my ASSUMPTION it's the same with dark matter. Whatever the energy level it's not matter they're talking about producing.
yyz
5 / 5 (8) Apr 06, 2011
From their paper, the authors posit that annihilating DM[ADM] (as opposed to other, non-annihilating types of DM postulated) could serve as a heat source in their scenario.

ADM is thought to produce copious gamma radiation as well as particle-antiparticle pairs, and observation of excess gamma radiation, positrons and antiprotons from the galactic center might constitute an indirect observation of it: http://en.wikiped...eriments

Unfortunately, detecting excess radiation-particles from the GC is complicated by similar emissions from known sources eg. neutron stars, SNe, X-ray binaries, even the SMBH Sag A*.

Untangling the contributions of these background sources from that expected from ADM is quite tricky, although recent observations by Fermi, PAMELA, Integral, and MAGIC are making strides in that direction:

http://arxiv.org/...22v1.pdf

http://arxiv.org/...52v3.pdf
yyz
5 / 5 (7) Apr 06, 2011
Although the GC region is obviously a good place to search for possible signs of ADM, several studies (using Fermi& MAGIC) have looked at several (dark matter dominated) dwarf galaxies of the MW and a few nearby galaxy clusters. Even though signs of ADM are thought to be weaker in these objects, they avoid problems with background sources that affect DM searches of the GC.

At this time though there have been no unambiguous signals of ADM from these objects (but useful constraints).
Pyle
1 / 5 (3) Apr 06, 2011
Quick thought.
The DM we are talking about here is composed of fermions. As a result, DM's attraction via gravity must overcome fermi pressure, in addition to dealing with near frictionless motion(nod to soulman), in order for large amounts of DM to form into dense structures.

Within large baryonic bodies, i.e. stars and planets, the DM might get trapped and achieve higher densities than outside, given the extra gravity.

To add to yyz's information, looking for signs of ADM in the GC and within other areas of dense baryonic matter may be the most likely way to find such signs. Out in open space the properties of DM would prevent significant numbers of interactions.

(Thanks to everyone. I understand DM-DM interactions better than several posts ago. Also, I hope I didn't imply I understood neutrino flavors well earlier. I don't.)
Ethelred
2 / 5 (4) Apr 06, 2011
FTA:
Read the paper. You know perfectly well the articles change things from the paper. It is short and much of it is a standard science paper header(who wrote it) and footer(who did they steal from).

Once a sufficient quantity of dark matter is captured, it can begin to annihilate efficiently, converting its mass into kinetic energy in the form of relativistic particles that are then absorbed by the surrounding material.
Gamma rays are not relativistic particles. That is going on the idea that a relativistic particle is a particle that is NEAR the speed of light and not a massless particle at the speed of light. There is no need to use the term 'relativistic particle' if they meant gamma rays. Unless it was a deliberate obfuscation of course.

Please keep in mind that I am discussing their ideas. I don't have to agree with them to do so.

More
Ethelred
2 / 5 (4) Apr 06, 2011
Whatever the energy level it's not matter they're talking about producing.
Relativistic particles sounds like matter to me. With a high KE since they are relativistic.

In any case since the key characteristic of DM is that we can't see it with telescopes I think Dark Matter is very good term for it. Now if you have a better term then you need to start using and spreading it immediately.

Stuff We Can't See But Can Detect Via Gravity Interactions Except When The Stuff Annihilates And Stops Being Particles. SWCSBCDVGIEWTSAASBP rolls right of the tongue in way not seen since MXYZPTLK showed up in Superman comics so I can see it catching on right away.

I think my spell check just died.

Ethelred
Tissa_Perera
1 / 5 (3) Apr 16, 2011
Is this the best that physicists at Fermilab can come up with?
"These WIMPs interact with regular matter by a weak nuclear force and gravity, but they are also antiparticles."
Come again
but they are also antiparticles.

If this is the case by now all DM in the universe should have anihilated each other long ago.
With all this speculation on DM, is it not simple to do more work on MOND? As I have a viable concept for modifying gravity.
/Tissa Perera
ShotmanMaslo
1 / 5 (2) Apr 16, 2011
If this is the case by now all DM in the universe should have anihilated each other long ago.


How do you know?
dogbert
1 / 5 (8) Apr 16, 2011
With all this speculation on DM, is it not simple to do more work on MOND?


No. Trying to determine the nature of gravity is hard. The simple thing to do is to use a kludge.
FrankHerbert
0.8 / 5 (51) Apr 16, 2011
KKKKKKKKKKKKKLLLLLLLLLLLLLUUUUUUUUUUUUUUUUUUDDDDDDDDDDDDDDGGGGGGGGGGGGGGGGGGEEEEEEEEEEEEEEEEEE

KLUDGE KLUDGE KLUDGE KLUDGE. GET A THESAURUS.
dogbert
1 / 5 (7) Apr 16, 2011
Do you have a problem with the word or with kludges, Frank?

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