New evidence for dark matter makes it even more exotic

October 26, 2017, Ecole Polytechnique Federale de Lausanne
Dark matter map of KiDS survey region (region G12). Credit: KiDS survey

Galaxy clusters are the largest known structures in the Universe, containing thousands of galaxies and hot gas. But more importantly, they contain the mysterious dark matter, which accounts for 27 percent of all matter and energy. Current models of dark matter predict that galaxy clusters have very dense cores, and those cores contain a very massive galaxy that never moves from the cluster's center.

But after studying ten galaxy clusters, David Harvey at EPFL's Laboratory of Astrophysics and his colleagues in France and the UK have discovered that the density is much smaller than predicted, and that the galaxy at the center actually moves.

Every contains a galaxy that is brighter than the others, aptly named "brightest cluster galaxy" or BCG. Recent evidence from simulations of exotic, non-standard dark matter shows that BCGs actually wobble long after the galaxy cluster has relaxed. This is residual wobbling caused by massive merging of galaxy clusters.

The researchers compared their observations to the predictions from the BAHAMAS suite of cosmological hydro-dynamical simulations finding that the two did not match. According to the Standard Model of dark matter (called "cold dark matter"), this wobbling doesn't exist because the enormous density of dark matter keeps it tightly bound at the center of the galaxy cluster. Therefore, this mismatch suggests the existence of yet-unknown physics that have not been accounted for.

The galaxy clusters that the astronomers studied also act as strong gravitational lenses: they are so massive that they warp spacetime enough to distort light passing through them, like a lens. As a result, they can be used to make a map of dark matter, working out where the center is and then observing how the BCG wobbles around this center.

"We found that that the BCGs 'slosh' around at the bottom of the halos," says David Harvey. "This indicates that, instead of a dense region in the center of the galaxy cluster, there is a much shallower central density—a striking signal of exotic forms of right at the heart of galaxy clusters." The wobbling also shows that BCGs cannot coincide exactly with the 's halo, meaning that certain models of galaxy clusters have to be adjusted.

The scientists will extend their research with larger surveys of galaxy clusters such as Euclid. They hope that this will allow them to confirm their findings, but to also determine if BCG wobbling originates in new fundamental physics or a novel astrophysical phenomenon.

Explore further: Mapping dark matter

More information: David Harvey et al. A detection of wobbling brightest cluster galaxies within massive galaxy clusters, Monthly Notices of the Royal Astronomical Society (2017). DOI: 10.1093/mnras/stx2084

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Bart_A
2.6 / 5 (20) Oct 26, 2017
As if dark matter weren't already exotic. Now some people want to label as super exotic. When we haven't even observed any of it.

Without more real information, I would classify DM as the world of fantasy and fairy tales.

Blakut
3.8 / 5 (18) Oct 26, 2017
Good that you're not an astrophysicist then.
someone11235813
5 / 5 (6) Oct 26, 2017
Galaxy clusters are the largest known structures in the Universe


Is this correct? I was under the impression that the galaxy clusters are clustered into super clusters which then form huge strings or sheets of superclusters.
Da Schneib
4 / 5 (13) Oct 26, 2017
No, evidence from observation contradicting the predictions of hypotheses about the CDM theory. Evidence comes from observation and experiment, and from logical reasoning, not from theories and hypotheses.

We'll want to keep an eye on this. This is very interesting. I hope @shavy or @IMP-9 or someone like that shows up and looks this over; their comments should be interesting.
Chris_Reeve
Oct 26, 2017
This comment has been removed by a moderator.
fthompson495
1.4 / 5 (10) Oct 26, 2017
There is evidence of the strongly interacting superfluid dark matter every time a double slit experiment is performed, as it is the dark matter that waves.
cantdrive85
1.7 / 5 (11) Oct 26, 2017
The researchers compared their observations to the predictions from the BAHAMAS suite of cosmological hydro-dynamical simulations finding that the two did not match. According to the Standard Model of dark matter (called "cold dark matter"), this wobbling doesn't exist because the enormous density of dark matter keeps it tightly bound at the center of the galaxy cluster. Therefore, this mismatch suggests the existence of yet-unknown physics that have not been accounted for.

The biggest problem they are having is they are plasma ignoramuses using models based upon gravity only gas dynamics to explain electrodynamic plasmas. But hey, I'm sure some clever guy will come along and propose some ad hoc band aid explanation to patch up this failure and falsification of their faerie dust conjectures.
shavera
4.4 / 5 (13) Oct 26, 2017
Over and over again, we've found observations that have very strongly matched predictions of GR, not least of which are the recent "gravitational" waves. So when we're faced with observations that don't match our predictions, we must look at our initial assumptions. Which in this case are two: Should we assume GR works? Should we assume that we have observed all the mass and energy in a system? We have overwhelming reams of evidence that GR works, and it's not entirely unreasonable to assume there are still kinds of mass and energy we don't yet know or understand. So it is more than reasonable to suppose our latter assumption, that we know all of the kinds of mass and energy, is the improper assumption.

So if we drop the assumption that we don't know all of the mass and energy, how can we investigate the unknown? Data such as these help tell us what the unknown stuff likely isn't. When we know all the stuff it isn't, we may know what it is.
cantdrive85
1 / 5 (10) Oct 26, 2017
Evidence comes from observation and experiment, and from logical reasoning, not from theories and hypotheses.

Is that how you discovered the magical magnetic monopole at the end of that "open field line" you were discussing not too long ago? That hack Kip Thorne has nothing on you, he had to share his pseudoscience prize whereas you will be awarded a solo prize given the magnitude of your discovery.
shavera
4.6 / 5 (11) Oct 26, 2017
To draw a mediocre parallel, we have known for ages that air is a thing. We feel variations in air pressure, see mirages due to variations in air density, note relationships between the heat in the air and its pressure, and so on. Not until relatively recently in human history were we able to find that air is made of molecules. Then after that, we found molecules are made of atoms. Then atoms are made of electrons and nuclei, that nuclei are made of hadrons, that hadrons are made of quarks and gluons. (though we have reason to believe the chain may likely stop there, which is beyond the scope of this comment).

So did we only know air existed when we knew the subatomic structure of air? Did we have to detect the individual air particles before we knew of air's existence? Or was its bulk behaviour sufficient to know it existed? So even if we don't know the particulate structure of unknown mass... its bulk behaviour is quite telling about its existence.
PTTG
4.7 / 5 (12) Oct 26, 2017
I honestly don't know what's more frightening: the idea that there's a massive horde of conspiracy theorists out there, or that there's a massively successful propaganda campaign against the idea of science itself.
shavera
4.7 / 5 (12) Oct 26, 2017
Ultimately your complaint is that you just don't agree with the foundational idea of physics, that if a model predicts outcomes to experiments, requiring fewer unfounded assumptions than other models, that model best describes reality. You seem to want physics to have precisely 0 unfounded assumptions. Which it can't, and likely won't.

If you throw a ball, you can calculate where that ball will land. But first you must assume (in the Newtonian approximation) that there is some external force acting on the ball, that motion falls under rules of inertia and momentum conservation, and so on. Modern physics is really just an extension of those kinds of assumptions, yet simplifying them (we no longer need to assume a 'force' of gravity exists, and momentum conservation rules come from a yet simpler rule (space/time translation symmetries)).
rossim22
2.5 / 5 (11) Oct 26, 2017
The number of ad hoc hypotheses associated with dark matter is bewildering.

There isn't "unknown physics" just waiting to be realized. The SIMPLE answer is that the standard model is wrong. It's that easy. Stop assuming that there MUST be dark matter because it fits your models. Models don't mean a damn thing when the environment those models are predicated upon doesn't exist.

Scrap the whole paradigm already, it's going to happen eventually.
Tuxford
1.8 / 5 (10) Oct 26, 2017
There isn't "unknown physics" just waiting to be realized. ...

Scrap the whole paradigm already, it's going to happen eventually.

The real problem is that physics does not have the sufficient tool set to explain nature, and likely never will. Since physics claims that authority regardless, any other tools brought to bear are ignored and ridiculed.

Yes, the double slit experiment yields a broad hint. But physics objects with constant repetition 'It is both an apple and an orange!' Sounds like Trumps world. Just as valid.

What universally present medium produces waves influencing matter and yet by definition cannot be detected? Overcome this objection with logical insight, and you are on your way.
shavera
4.6 / 5 (11) Oct 26, 2017
The SIMPLE answer is that the standard model is wrong.

Obviously. Physicists know it's wrong. We just don't know what the next, more accurate, model is.
he environment those models are predicated upon doesn't exist.

The standard model doesn't really inform anything about dark matter one way or the other right now. GR is why we think there's dark matter. GR is remarkably accurate across a lot of experiments. So how do you explain GR being so right so often, but not in this case? As I say above, it seems easier to suppose that there's a kind of mass or matter we don't yet know about.

And that, in turn, is where we circle back to your complaint about the standard model of particle physics. If there's a kind of mass or energy out there we don't know about, and we know the standard model is incomplete... it seems pretty reasonable to guess that our next correction of the SM will allow us to know more about that unknown mass/energy.
Benni
1.4 / 5 (11) Oct 26, 2017
we've found observations that have very strongly matched predictions of GR


Shavo, you complete & total GR Illiterate. There's not one word in Einstein's GR about your silly DM Cosmic Fairy Dust. Where? What section?

Schneibo begs you to bring your wordsmithing skills here because that's what he imagines this site needs, more of your freelance journalism skills.

Look, I know guys like you have a BMI problem, you turn sideways while looking in a mirror, and VOILA, missing mass located, but you won't let the rest of us see it. Pics please.

shavera
4.7 / 5 (13) Oct 26, 2017
Oh benni, you complete and total illiterate. I mean if you were literate you might be able to read. Maybe if you could read you wouldn't have to make up nonsense and claim I said it. Maybe if you could read, you could read any physics textbook once in your life.

Please quote exactly where I claim GR talks about Dark matter. Where? What section?

Because if I'm not mistaken, I say no such thing. I say merely that GR seems to be right in a lot of ways, and maybe physicists aren't so stupid as to imagine that we know all of the kinds of mass and energy in our universe. Especially when we know our standard model of particle physics is already incomplete. So maybe it isn't unreasonable to assume there's stuff out there we don't know about.

antialias_physorg
4.6 / 5 (11) Oct 26, 2017
The standard model doesn't really inform anything about dark matter one way or the other right now. GR is why we think there's dark matter.

One should also look at how the alternative models are doing.
E.g. with the recent observation of the neutron star merger a lot of the MOND theories died (not all, but a whole slew). These MOND theories predicted that gravity would couple differently to spacetime than EM over long distances. But since the speed of the light and the gravitational wave were the same (they both arrived here at the same time) that idea fizzled out.
The standard model is still the best we have.
shavera
4.4 / 5 (7) Oct 26, 2017
I wasn't particularly clear above, I guess, when I hear "standard model" it's always 'of particle physics' to me.
Da Schneib
3.9 / 5 (7) Oct 26, 2017
@shavy, thanks for weighing in. I didn't see where I could add anything or anything wrong with what you said. @IMP-9 might give us some additinal astrophysics insight but I doubt there is any reasonable arguing with @Lennitheluser.
Benni
1.7 / 5 (12) Oct 26, 2017
shavo,

Please quote exactly where I claim GR talks about Dark matter


we've found observations that have very strongly matched predictions of GR, not least of which are the recent "gravitational" waves


.......right there, you lumped your Cosmic Fairy Dust right alongside gravitational waves as a strongly matched prediction of GR. The only place missing DM mass can be observed is when you're looking sideways in a mirror at your BMI, the same problem almost all freelance journalists like you have.

So the challenge to you again: Produce the section of GR for which predictions of DM are found.

Why not admit the obvious, that you simply did not know what you were talking about & you were hoping I wouldn't be here to catch it.

Mimath224
4.2 / 5 (5) Oct 26, 2017
Well, I am not going to ask any questions here today because I figure there are enough of them flying around already. But I have to say that scientist do come out with some everyday or common expressions that just makes me smile. '...'slosh' around at the bottom...' That certainly conjures up some wonderful impressions in my mind. Where is our artist expert WG, would like to hear about his thoughts on that. Since this might be happening in a massive but confined space I wonder if Glug quanta and Glug Quanta Frequency (fluid dynamics) are relevant, if the contents ever 'pour' (ejected) out that is...just joking.
Whydening Gyre
4.2 / 5 (5) Oct 26, 2017
Well, I am not going to ask any questions here today because I figure there are enough of them flying around already. But I have to say that scientist do come out with some everyday or common expressions that just makes me smile. '...'slosh' around at the bottom...' That certainly conjures up some wonderful impressions in my mind. Where is our artist expert WG, would like to hear about his thoughts on that.

I just make artsy stuff... I'm no expert...:-)
I have no idea what they meant by that metaphor...
That the densest portion of a cluster can be just bout anywhere within it? Or that lensing is done the same by a cluster regardless of galaxy positioning within it?
However, I AM developing an opinion on the nature of DM...:-)
rossim22
2 / 5 (8) Oct 26, 2017
Obviously. Physicists know it's wrong. We just don't know what the next, more accurate, model is.
... GR is why we think there's dark matter. GR is remarkably accurate across a lot of experiments. So how do you explain GR being so right so often, but not in this case?


Dark matter isn't just another ad hoc detail, it's a paramount foundational element of today's GR.

Here's a mediocre parallel.

Back when humans "knew" the earth was in the center of the universe, it too explained the observations extremely well. There were beautiful models produced and predictions could even be made upon these ideas.

Eventually, conflicting observations, such as eclipse tables, began to appear. Geocentric models could still explain these to a tee, however, the originally simplistic model (geocentrism) had to become exponentially more complex to do so.

Copernicus' idea made the same predictions yet required fewer assumptions.

GR used to be simple.. in the 40s.
rossim22
1.6 / 5 (7) Oct 27, 2017
Humans became able to observe a galaxy in unprecedented detail, even tracking its rotation. We learned that, according to GR, the galaxy was rotating too fast to contain its mass... uh oh!

But that's not all folks. That same galaxy's rotational velocity was nearly the same whether you were circling the core or surfing the outer fringes, nothing like GR would predict (insert spinning ballerina or whirlpool metaphor here).

So GR already explained everything 'beautifully', then this wrench got thrown into the mix. To keep GR afloat all we have to do is.. invent an entire new realm of physics to help explain a rotation issue. Wow.
But I'm coined a conspiracy theorist because I think there may be a simpler explanation.

Confirmational bias (or researcher's bias) can Ben awfully misleading.
Dark energy shares a very similar story.
Ojorf
3.7 / 5 (7) Oct 27, 2017
Gee Benni, did you really not get what shavera meant? You really need to read up on the basics. Just three things.

Observations:
1. Spacetime is as flat as we can measure.
2. Galaxy rotation curves.
3. Gravitational lensing.

Take GR as an accurate enough description of reality.
What does GR tell us about the content of the universe given 1 above?
What does GR imply about 2 and 3?

Do you see what I'm getting at? There are more examples.

Can you answer? Simply and straightforward? Without quoting stuff?

What does Einsteins GR say about the universe, given these observations?
Gigel
5 / 5 (3) Oct 27, 2017
I wonder when you people will be getting tired of fighting trolls and put them on the ignore list. It will do you good.
Mimath224
4.6 / 5 (9) Oct 27, 2017
@Benni
we've found observations that have very strongly matched predictions of GR


Shavo, you complete & total GR Illiterate...
Look, I know guys like you have a BMI problem, you turn sideways while looking in a mirror, and VOILA, missing mass located, but you won't let the rest of us see it. Pics please.


And there you go again '...guys like you...'?! Has shavera disclosed gender too? Or maybe you live in a one gender universe where the mysterious DM might be the missing...you know...the other gender.
Even a layman like me has read nothing where GR predicts DM so there is no way shavera would make such a claim. Great Caesar's Ghost, Einstein had enough problems with the Cosm. Constant let alone GR predicting DM or DE...I'm posting on the lighter side, of course.
Benni
1.5 / 5 (8) Oct 27, 2017
1.Spacetime is as flat as we can measure


Proving you don't even comprehend the concept of "spacetime", here:

Gravity is strongest where spacetime is most curved in the presence of massive bodies of matter, and it vanishes where spacetime is flat. In physics, spacetime is any mathematical model that fuses the three dimensions of space and the one dimension of time into a single four dimensional continuum.

2. Galaxy rotation curves.


This applies only to SPIRAL GALAXIES which make up only 1/3 the mass of the Universe, read what your asstrophysicist icon Fritz Zwicky actually wrote.

3.Gravitational lensing


You don't even know what section of GR to find Einstein's calculations for this & the fact that he calculated the process long before Zwicky conjured up his DM Halo theories specific to Spiral Galaxies.

This is fun, just love the endless psycho-babble pseudo-science you overage Trekkies won't give up, it's the only reason I post Comments
nikola_milovic_378
Oct 27, 2017
This comment has been removed by a moderator.
Ojorf
4 / 5 (9) Oct 27, 2017
Nice Benni, so you couldn't even answer one of them.
No surprises there, although I was hoping.
Ojorf
4.4 / 5 (8) Oct 27, 2017
We don't "observe" Flat "spacetime". We observe space as a 3D volume...it is mathematically derived as "flat" ONLY in the context of GR and "spacetime".

I'm talking about the universe as a whole, 3D space can be flat, positively curved (open) or negatively curved (closed, saddle shaped) according to GR.
Since, according to GR, Matter (and energy) curves space the shape of the universe depends on the amount of matter (etc.) it contains.
According to experiment/observation (WMAP, BOOMERanG, and Planck for example) the observable universe is flat with only a 0.4% margin of error.
Ojorf
4.4 / 5 (8) Oct 27, 2017
Proving you don't even comprehend the concept of "spacetime", here:

Gravity is strongest where spacetime is most curved in the presence of massive bodies of matter, and it vanishes where spacetime is flat. In physics, spacetime is any mathematical model that fuses the three dimensions of space and the one dimension of time into a single four dimensional continuum.


You totally missed the point, as usual, see above.
We are not talking about any formulas, just the basic principles.
Do you get that the shape of the universe depends on what it contains?
Benni
1.5 / 5 (8) Oct 27, 2017
Do you get that the shape of the universe depends on what it contains?


.....and herein is what Einstein had to say about that in GR:

Part III: Considerations on the Universe as a Whole- the structure of Space
Albert Einstein – General Relativity 1916

"If we are to have in the universe an average density of matter which differs from zero, however small may be that difference, then the universe cannot be quasi-Euclidean. On the contrary, the results of calculation indicate that if matter be distributed uniformly, the universe would necessarily be spherical (or elliptical). Since in reality the detailed distribution of matter is not uniform, the real universe will deviate in individual parts from the spherical, i.e. the universe will be quasi-spherical. But it will be necessarily finite. In fact, the theory supplies us with a simple connection between the space-expanse of the universe and the average density of matter in it."

......and this ain't exactly flat.
Ojorf
4.5 / 5 (8) Oct 27, 2017
Oh boy, missing the point, quoting thins out of context.

Is this wrong? https://map.gsfc....ape.html

Cause Einstein would sure agree with it.

Benni, please read this and tell me what exactly you disagree with:

https://en.wikipe...universe

What part exactly is wrong?

There are references and everything, which ones don't you like?
Ojorf
4.4 / 5 (7) Oct 27, 2017
``Only two things are infinite, the universe and human stupidity - and I'm not sure about the former.'' - Albert Einstein

See Einstein thought the universe was probably flat.
Since then experiment proved him right, on both counts.
Benni
1 / 5 (7) Oct 27, 2017
go fly around space until you find it's flat surface. All the math in the world won't help you find one when traversing a volume, unless you encounter an object...


@bshott.......only thing flat around here are a few brainwaves from the usual Perpetual Motion crowd living in the Commentary section on this site. They're also the same ones who think we can see leftover big bang energy because somehow the Milky Way has magically found a way to stay in front of electro-magnetic waves traveling at 186,000 miles/s.
Whydening Gyre
4.4 / 5 (7) Oct 27, 2017
go fly around space until you find it's flat surface. All the math in the world won't help you find one when traversing a volume, unless you encounter an object...


@bshott.......only thing flat around here are a few brainwaves from the usual Perpetual Motion crowd living in the Commentary section on this site. They're also the same ones who think we can see leftover big bang energy because somehow the Milky Way has magically found a way to stay in front of electro-magnetic waves traveling at 186,000 miles/s.

We see it all AROUND us. Ergo, we're not "out in front of"...
Whydening Gyre
4 / 5 (4) Oct 27, 2017
We don't "observe" Flat "spacetime". We observe space as a 3D volume...it is mathematically derived as "flat" ONLY in the context of GR and "spacetime".

I'm talking about the universe as a whole, 3D space can be flat, positively curved (open) or negatively curved (closed, saddle shaped) according to GR.
Since, according to GR, Matter (and energy) curves space the shape of the universe depends on the amount of matter (etc.) it contains.
According to experiment/observation (WMAP, BOOMERanG, and Planck for example) the observable universe is flat with only a 0.4% margin of error.

I always thought it was .04%...
Da Schneib
2.3 / 5 (3) Oct 27, 2017
@Lennitheluser and @bullschott posting the Einstein quote about human stupidity is the ultimate in irony. Thanks for adding to the ambience of physorg, #physicscranks.

It's especially amusing to be watching these #physicscranks melt down while listening to Friday Night in San Franciso, di Meola, de Lucia, and McLaughlin rock out incredibly on acoustic axes. Perhaps one of the greatest performances on acoustic guitar in the 20th century.
Benni
1 / 5 (2) Oct 28, 2017
It's especially amusing to be watching these #physicscranks melt down while listening to Friday Night in San Franciso, di Meola, de Lucia, and McLaughlin rock out incredibly on acoustic axes. Perhaps one of the greatest performances on acoustic guitar in the 20th century.


Last night I was sitting around our huge crackling fireplace with the kids while playing my Gibson Hummingbird guitar in strumming out & singing Rocky Mountain High, then we did The Mountain Song, then I did my finger picking style of Sunshine On My Shoulders. John Denver is our musical icon. My wife plays piano & flute, while the kids have become adept in some kind of musical instrument.
Benni
1 / 5 (2) Oct 28, 2017
It's especially amusing to be watching these #physicscranks melt down while listening to Friday Night in San Franciso, di Meola,


Naw, we didn't "melt down", we maintained a safe distance from the fireplace, it was really way more fun making our own music than just listening to somebody else.
Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Chris_Reeve
Oct 28, 2017
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Mimath224
4.1 / 5 (9) Oct 28, 2017
@Chris_Reeve What is with you quoting various passages from here and there. We could all do that from sources that praise GR. Why not do some ORIGINAL thinking and tell us how YOU refute GR. That would be far more interesting.
Whydening Gyre
4.5 / 5 (8) Oct 28, 2017
@Chris_Reeve What is with you quoting various passages from here and there. We could all do that from sources that praise GR. Why not do some ORIGINAL thinking and tell us how YOU refute GR. That would be far more interesting.

MM.
Very similar to what i commented to him in another thread...
https://phys.org/...ons.html
You made a good point about originality. His constant references to the writings(and beliefs) of OTHERS seems to single him out as NOT original. More, blindly following what others have to espouse...
Da Schneib
3 / 5 (4) Oct 29, 2017
But I have to say that scientist do come out with some everyday or common expressions that just makes me smile. '...'slosh' around at the bottom...'
That's actually pretty quantifiable in fluid mechanics terms. And those types of behaviors don't work very well within the parameters generally developed for how dark matter "ought to" behave.

Meanwhile thanks for weighing in, @shavy. You gave me some things to think about.
cantdrive85
1.8 / 5 (10) Oct 29, 2017
You made a good point about originality. His constant references to the writings(and beliefs) of OTHERS

The irony is rich, on one hand most here demand where the claims appear in the science literature and then on the other claim one is not being original when they do so. And all seem to be missing the issues CR is commenting on, scientific controversies. Is it really a "valid" scientific controversy if it is brought to bare by the opinions of random guy on the interweb? I think I know how that would go over, by posting the comments by known and published scientists it gives more creedence to the claims. Think of CR as the Phys.org of scientific controversies, more of an aggregation guy than an actual source.
Chris_Reeve
Oct 29, 2017
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Chris_Reeve
Oct 29, 2017
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ShotmanMaslo
5 / 5 (6) Oct 29, 2017
The irony here is that there is only way out of this dark matter problem: You HAVE to start expanding the circle of ideas you're listening to -- because, in terms of process, what's happening right now is not working.


If you expand your mind too much you will end up in pseudoscience territory. For example, no matter how many problems scientific theories have, there is no reason to expand the circle until flat Earth is considered as an alternative model. Your primitive ramblings are a clear example of this, you just regurgitate almost anything you read with no discrimination.

Also there is no censorship and no limiting of ideas in physics. Plenty of very speculative and weird ideas are pursued in the hope of providing answers, including alternatives to dark matter such as MOND. But the idea must have at least some merit, to distinguish itself from mere random nonsense such as electric universe or denial of relativity.
katesisco
1 / 5 (3) Oct 29, 2017
Has there been suggestions that this matter is the unusual form of non-bonding structure? Monoatomic elements and superconducting at Zero K?
torbjorn_b_g_larsson
5 / 5 (6) Oct 29, 2017
If you like science, this should be very interesting. To first field some misunderstandings here, dark matter is evidenced from many different types observations such as the cosmic microwave background and is neither 'ad hoc' nor in question in physics. Neither is GR nor standard particle description, but they are also known to be incomplete which some of the comments note. And space, regardless of spacetime physics, is observed as perfectly flat from the cosmic microwave background spectra.

There has also been questions about the nature of cold dark matter, which is the actual topic of the article.

[tbctd]
Da Schneib
4 / 5 (4) Oct 29, 2017
Good a real astrophysicist. Tell it @torbjorn.
torbjorn_b_g_larsson
5 / 5 (5) Oct 29, 2017
[ctd] To quote the old astrobite about the preprint article:

"So far, astrophysical observations have taught us that dark matter is not relativistic (it's "cold"), it's not electrically charged (or it would interact with photons through the electromagnetic force and we would be able to see it!), and it can't have more than very rare interactions with normal matter through any force but gravity.

However, there are many things we still don't know about dark matter particles (in addition to the big one – what are they?), including the question addressed in today's paper – how do dark matter particles interact with each other? Do they pass through each other like they have passed through our detectors? Or can they bump into and scatter off of each other?"
[ https://astrobite...actions/ ]

[tbctd]
torbjorn_b_g_larsson
5 / 5 (5) Oct 29, 2017
[ctd]

Immediately we understand that it is called "dark" and is non-atomic because we can see that it does not interact much by electromagnetic force.

Continuing on, the reported paper seems convincing and interesting. It notes that in other cases of tension between theory and observations, a better understanding of galaxies can remove that. But in this case we may face the observation that dark matter, as all other particles, self-scatter.

@Da Schneib: Not me, I am a bioinformatician with astrobiology interest (and physics background).
Mimath224
4.4 / 5 (7) Oct 29, 2017
@cantdrive85
You made a good point about originality. His constant references to the writings(and beliefs) of OTHERS

The irony is rich, on one hand most .... Think of CR as the Phys.org of scientific controversies, more of an aggregation guy than an actual source.


Nope, I think you got that wrong. I was asking CR for his OWN opinion. Many here comment from there own experience, working in the field etc. I have made it clear that I am a layman but intimated where my opinion comes from. If someone doesn't agree with my stance that's fine and if I'm corrected I don't mind that either because I learn something. I don't hide behind a myriad of quoted passages from other sources as CR seems to do. The author's of those passages are not on this forum to converse with. If CR has formed a personal opinion let's hear it and discuss it.
IMP-9
3.7 / 5 (6) Oct 29, 2017
@Da Schneib it looks like an interesting paper and the BAHAMAS team and Ian McCarthy in particular do very interesting work. It's an interesting claim which has been around before, it would be prudent however to ask for comparable simulations of clusters like this in warm and self-interacting dark matter. An important question remains of whether the modification you need is compatible with other observational constraints. If not then something else is happening. I'm cautious as many of these claims don't last more than a few years.
Benni
1 / 5 (7) Oct 29, 2017
An important question remains of whether the modification you need is compatible with other observational constraints. If not then something else is happening. I'm cautious as many of these claims don't last more than a few years.


Just love bouncing off zany stuff like this.

I guess you don't know in the 1930's Fritz Zwicky originally proposed that DM should ONLY exist in halos enveloping ONLY Spiral Galaxies, this as a proposed counter gravitational mass to keep spiral arms from imploding into the central hub.

Since the 1930's, the DM narrative about INFERRED GRAVITY has morphed into permeating EVERYTHING with the exception of ONLY our the solar system in which we live where none can be found.......talk about pseudo-science, yeah, coming from zany Zwicky who got off on calling real scientists like Einstein "spherical bastards" for dis-believing his concepts of Tired Light & Rocket Engines being inoperable outside the atmosphere.

Da Schneib
3.4 / 5 (5) Oct 29, 2017
@torbjorn, thanks! That was very useful. The point about DM self-interacting was not clear to me before now. I may add astrobites to my favorites.
Da Schneib
3.4 / 5 (5) Oct 29, 2017
@IMP, thanks for your take on this. Hopefully we get more constraining observations, and more powerful simulations, in the near future. The JWST should help with the first; who do you see doing work on the second?
Chris_Reeve
Oct 29, 2017
This comment has been removed by a moderator.
cantdrive85
1 / 5 (6) Oct 29, 2017
Hey da schnied, maybe you could convince torby larsen or the gimp-0 to comment on your claims of the "open field lines" and the magnetic monopole you claimed to have discovered. I'm sure that would be interesting...
Chris_Reeve
Oct 29, 2017
This comment has been removed by a moderator.
Benni
1 / 5 (4) Oct 29, 2017
This is not how we will get to the answers. It's how we will spin our wheels for another century. People need to be regularly confronted with their critics when theories become challenged. That is the spirit of science which creates progress.


Well, it's not advancing concepts Schneibo & that cadre of Perpetual Motion Mechanics living here, and besides, you must by now be encroaching on Schneibo's domain for leader of total cyberspace consumed in putting up Commentary........man, where do you guys find the time?
Chris_Reeve
Oct 29, 2017
This comment has been removed by a moderator.
fastermx
4.6 / 5 (5) Oct 29, 2017
All people seem to be doing here is quibbling. I'm no scientist, but my father was a pioneer in Biochemistry and in his day was renowned. He was a wise man.

And that wisdom one time came in this form: "I always listen to the quacks." I asked him why, and he said it was because many innovators in science were often called quacks at first. He listened to quacks in case that particular "quack" might happen to be one of them.

I think all the quibblers should just listen to what is said, and if they are scientists, do their own research to sharpen our knowledge of dark matter. We're only in the infancy of trying to study it. So why make hard statements? A wait-and-see approach is best, plus doing your own research, if you're qualified and able.

It's a shame that personality is injected into science. It slows the process to inject egos, orthodoxy and attitudes into the mixture. It also helps a lot to know the difference between attitude and opinion
Mimath224
5 / 5 (3) Oct 29, 2017
@fastermx Well, that's fine...up to a point. My father was an engineer but veered to the philosophical side of things. He would argue that 'quacks' are generally people who do something for their own gain (maybe even fraudulent) but people with a difference of opinion would be 'rebels' if they were extreme in attitude or simply an 'objector' if their opinions were opposite to mainstream but worthy of consideration.
So I'm inclined to say that 'quack' isn't really the right noun for those who have been cited in this thread or those here who maintain a different stance to mainstream physics.
As for attitudes, egos etc. unless you are a robot such overlaps are bound to happen and as long as there is some self control I don't think it harms science. Indeed, a passion to seek the truth (or result) is often the driving force for progress.
Whydening Gyre
5 / 5 (4) Oct 30, 2017
MM and faster,
Not least to mention... this is a science article aggregagation site, not an actual science site...
And we can see now, that Chris isn't actually reading all of those papers he quotes. He just snips and pastes Quotes...
Not very scientific...
Captain Stumpy
3.4 / 5 (5) Oct 30, 2017
And that wisdom one time came in this form: "I always listen to the quacks."
@fastermx
there is a big difference between listening and accepting their ideas on faith
- and considering your fathers field of expertise, the one thing i can guarantee is that he accepted no pseudoscience, especially if it had no empirical evidence or predictability and it was directly contradicted by evidence, experimentation and observation

what you're seeing with certain posters above fighting against the idiocy isn't "egos, orthodoxy and attitudes" so much as it's a long, exasperating fight against the spread of pseudoscience and outright fraudulent claims

see also: https://www.youtu...EwjBXlZE

far too many people assume the comments in this news aggregate are a source of science - and they have no critical thinking skills or ability to differentiate science from pseudoscience

Captain Stumpy
3.4 / 5 (5) Oct 30, 2017
@fastermx cont'd
We're only in the infancy of trying to study it. So why make hard statements?
there are some hard statements that can be made, especially against certain types of pseudoscience

for instance: chris_reeve (also hannesalfven) believes in the electric universe pseudoscience (hereafter "eu")

the eu is debunked very thoroughly by multiple sources, evidence, physics and their complete lack of anything other than claims (making them a religious cult, not anything scientific)

so you can make a hard claim about the eu
that doesn't mean they don't occasionally get something correct, mind you - but hard statements can be made about their beliefs, much like you can debunk creationists, aether advocates or most other religions (except the flying spaghetti monster - obviously that must be true)

PS - this has been going on for years, BTW, and the eu cultists have created multiple socks to continue their advocacy for their beliefs
CarnSoaks
not rated yet Oct 31, 2017
The researchers compared their observations to the predictions from the BAHAMAS suite of cosmological hydro-dynamical simulations. According to the Standard Model of dark matter (called "cold dark matter"), this wobbling doesn't exist because the enormous density of dark matter keeps it tightly bound at the center of the galaxy cluster. ...suggests the existence of yet-unknown physics that have not been accounted for.

The biggest problem they are having ... But hey, I'm sure some clever guy will come along and propose some ad hoc band aid explanation to patch up this failure and falsification of their faerie dust conjectures.


are these peoples considering the orbital mechanics / phenomenon like precession. Does not every object in an orbit, orbit about a shared centre of mass. Nothing is stationary, always some MORE mass out there in a system causing some WOBBLE. eg mercury, eg Sun eg mergers
IMP-9
5 / 5 (2) Oct 31, 2017
@IMP, thanks for your take on this. Hopefully we get more constraining observations, and more powerful simulations, in the near future. The JWST should help with the first; who do you see doing work on the second?


Allegedly the Illustris team are working on self-interacting dark matter clusters. I know there was also some work being done in Europe on it but I don't know if the latter actually includes galaxies, I believe the simulations were more tuned towards cluster mergers like the Bullet Cluster.
Da Schneib
not rated yet Oct 31, 2017
Thanks @IMP. Sounds like there aren't many players in this space yet. Is it mostly a matter of the programming difficulty, or is it the hardware?
Mimath224
not rated yet Oct 31, 2017
I have just read an article published yesterday in Physics by Dan Hooper of the Fermi Accelerator Lab .Batavia, USA. It mentions the XENON and PandaX-II collaborations and how no detections have been made.This one of the quotes; 'For a dark matter particle with a mass of 100 GeV, for example, each of these collaborations rule out cross sections for such interactions that are larger than about 10^−46 cm^2, per nucleon ' and another quote is '...The dark matter, it turns out, is not what many of us in the particle theory community imagined it was likely to be...'
I do realize that this speaks of ground base detection concerning our own local, but I'm just wondering on the general point that if we are unable to detect DM candidate particles here just how much more difficult does that make it for extra galactic DM? I would appreciate comments that might put any interpretation by me into correct perspective. Thanks in advance.

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