Dark Matter and Punching Holes:

Status
Not open for further replies.
P

paddoboy

Valued Senior Member
Massive holes 'punched' through a trail of stars likely caused by dark matter
September 7, 2016 by Sarah Collins

Artist's impression of dark matter clumps around a Milky Way-like galaxy. These clumps are invisible and can only be detected through their gravitational effect on visible matter. The clumps, also known as subhaloes, come in a range of sizes with the smallest one set by the mass of the yet to be discovered dark matter particle. The more massive the dark matter particle, the slower the dark matter moves, and the easier it is for regions in the early universe to collapse and form small subhaloes. In this work, a tidal stream from a disrupting globular cluster is used to probe their presence. Credit: V. Belokurov, D. Erkal, S.E. Koposov (IoA, Cambridge). Photo: Color image of M31 from Adam Evans. Dark matter clumps from Aquarius, Volker Springel (HITS)
The discovery of two massive holes punched through a stream of stars could help answer questions about the nature of dark matter, the mysterious substance holding galaxies together.



Read more at: http://phys.org/news/2016-09-massive-holes-trail-stars-dark.html#jCp
 
http://arxiv.org/pdf/1609.01282v1.pdf

A sharper view of Pal 5’s tails: Discovery of stream perturbations with a novel non-parametric technique

ABSTRACT
Only in the Milky Way is it possible to conduct an experiment which uses stellar streams to detect low-mass dark matter subhaloes. In smooth and static host potentials, tidal tails of disrupting satellites appear highly symmetric. However, dark perturbers induce density fluctuations that destroy this symmetry. Motivated by the recent release of unprecedentedly deep and wide imaging data around the Pal 5 stellar stream, we develop a new probabilistic, adaptive and non-parametric technique which allows us to bring the cluster’s tidal tails into clear focus. Strikingly, we uncover a stream whose density exhibits visible changes on a variety of angular scales. We detect significant bumps and dips, both narrow and broad: two peaks on either side of the progenitor, each only a fraction of a degree across, and two gaps, ∼ 2 ◦ and ∼ 9 ◦ wide, the latter accompanied by a gargantuan lump of debris. This largest density feature results in a pronounced inter-tail asymmetry which cannot be made consistent with an unperturbed stream according to a suite of simulations we have produced. We conjecture that the sharp peaks around Pal 5 are epicyclic overdensities, while the two dips are consistent with impacts by subhaloes. Assuming an age of 3.4 Gyr for Pal 5, these two gaps would correspond to the characteristic size of gaps created by subhaloes in the mass range of 106−107M and 107−108M respectively. In addition to dark substructure, we find that the bar of the Milky Way can plausibly produce the asymmetric density seen in Pal 5 and that GMCs could cause the smaller gap.
 
paddoboy said:
Massive holes 'punched' through a trail of stars likely caused by dark matter
September 7, 2016 by Sarah Collins

Artist's impression of dark matter clumps around a Milky Way-like galaxy. These clumps are invisible and can only be detected through their gravitational effect on visible matter. The clumps, also known as subhaloes, come in a range of sizes with the smallest one set by the mass of the yet to be discovered dark matter particle. The more massive the dark matter particle, the slower the dark matter moves, and the easier it is for regions in the early universe to collapse and form small subhaloes. In this work, a tidal stream from a disrupting globular cluster is used to probe their presence. Credit: V. Belokurov, D. Erkal, S.E. Koposov (IoA, Cambridge). Photo: Color image of M31 from Adam Evans. Dark matter clumps from Aquarius, Volker Springel (HITS)
The discovery of two massive holes punched through a stream of stars could help answer questions about the nature of dark matter, the mysterious substance holding galaxies together.



Read more at: http://phys.org/news/2016-09-massive-holes-trail-stars-dark.html#jCp
Click to expand...

But I thought all the efforts to detect dark matter failed miserably.
 
The God:

The God said:
But I thought all the efforts to detect dark matter failed miserably.
Click to expand...
That is so. They have interpreted observational data to infer non-baryonic etc DM, but have yet to actually detect it. To some (you know who), 'interpretation' and 'inference' are equivalent to 'evidence' for non-baryonic DM. The science method must suffer through and withstand such facile ignorance on the part of pop-sci writers and incompetent sci-journalists (like the one who wrote the ten years old article linked by you-know-who) who so readily confuse and mischaracterize even such simple and easy to understand subtle but important differences while claiming evidence and existence of things yet to be actually detected. Best.
 
expletives deleted said:
That is so. They have interpreted observational data to infer non-baryonic etc DM, but have yet to actually detect it. To some (you know who), 'interpretation' and 'inference' are equivalent to 'evidence' for non-baryonic DM. The science method must suffer through and withstand such facile ignorance on the part of pop-sci writers and incompetent sci-journalists (like the one who wrote the ten years old article linked by you-know-who) who so readily confuse and mischaracterize even such simple and easy to understand subtle but important differences while claiming evidence and existence of things yet to be actually detected. Best.
Click to expand...

Again, expletives deleted, you Post what any cognizant adult must only fully concur...Grok'd!!!
 
expletives deleted said:
The God:


That is so. They have interpreted observational data to infer non-baryonic etc DM, but have yet to actually detect it. To some (you know who), 'interpretation' and 'inference' are equivalent to 'evidence' for non-baryonic DM. The science method must suffer through and withstand such facile ignorance on the part of pop-sci writers and incompetent sci-journalists (like the one who wrote the ten years old article linked by you-know-who) who so readily confuse and mischaracterize even such simple and easy to understand subtle but important differences while claiming evidence and existence of things yet to be actually detected. Best.
Click to expand...
Sorry, the inference you as usually try and reflect is totally wrong, and you expressed that also in the other DM thread.
Why do you chose to ignore the science, in preference to your own fabricated ideas?
DM most certainly has been evidenced just as I said. The Bullet Cluster was an example of that data.
http://chandra.harvard.edu/press/06_releases/press_082106.html
Certainly as yet, we do not know the nature of all this DM, but according to the evidence, it is there.
 
Note the following:

paddoboy said:
Sorry, the inference you as usually try and reflect is totally wrong, and you expressed that also in the other DM thread.
Why do you chose to ignore the science, in preference to your own fabricated ideas?
DM most certainly has been evidenced just as I said. The Bullet Cluster was an example of that data.
http://chandra.harvard.edu/press/06_releases/press_082106.html
Certainly as yet, we do not know the nature of all this DM, but according to the evidence, it is there.
Click to expand...
The author of the above quoted post cannot distinguish between his/their DM inference, and my observation that it so far is only just that, his/their inferences 'for' NON-EM type DM. Not a good start. Then he proceeds to mischaracterize what I point out to him, which either means he didn't understand or is using tactics to evade conceding the point. You are free to reach your own conclusions based on the posts from the him so far. He also doesn't know that much ordinary E-M interacting matter (which was previously 'dark' but now detectable by our new scopes) explains much of the observed motions and distributions; which makes all the NON-EM type interpretations, inferences and explanations now unnecessary. How long will it take for him/them to catch up with the fact that the actual detected ordinary EM-interacting matter is the real evidence against non-EM DM hypotheses and claims to date? Which real evidence makes non-EM DM hypotheses, inferences, interpretations and pop-sci etc 'explanations' unnecessary. One must be patient with slow learners, especially when they confuse, mischaracterize and just plain miss every subtle but important distinction at the drop of a 'paddoby' hat.
 
Last edited:
DM is an accepted part of mainstream cosmology at this time, and has been evidenced many times.
While its nature remains inconclusive the evidence for its existence does not.

https://arxiv.org/pdf/hep-ph/0002126v1.pdf

Non-Baryonic Dark Matter: Observational Evidence and Detection Methods

Lars Bergstr¨om Department of Physics, Stockholm University, Box 6730, SE-113 85 Stockholm, Sweden, lbe@physto.se

Abstract.
The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational information points to the existence of a non-baryonic component, contributing between around 20 and 40 percent of the critical mass density needed to make the universe geometrically flat on large scales. In addition, an even larger contribution from vacuum energy (or cosmological constant) is indicated by recent observations. To the theoretically favoured particle candidates for non-baryonic dark matter belong axions, supersymmetric particles, and of less importance, massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. Direct and indirect methods for detection of supersymmetric dark matter are described in some detail. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the coming years.

. Conclusions and outlook
To conclude, we have seen that the existence of dark matter is more needed than ever, in order to explain a wealth of new observations. In addition to a large density of matter of unknown composition, the universe seems to contain also a large quantity of dark energy, of even more mysterious origin. Since the success of big bang nucleosynthesis combined with the measured intensity of the microwave background greatly constrains the amount of baryonic matter allowed, the major part of the matter density seems to be of non-baryonic origin. The standard big bang model contains the required mechanism to create a relic density of electrically neutral, stable particles which, if their interactions are of electroweak strength, may be perfect candidates for dark matter. Foremost of these candidates are the hypothetical supersymmetric partners of electrically neutral ordinary particles, motivated by current thinking in particle physics. Also the more weakly interacting low-mass axions which were invented to solve the strong CP problem are attractive dark matter candidates, probed by sensitive on-going experiments. Both direct and indirect detection methods have the potential of investigating supersymmetric and similar massive particle dark matter candidates. In particular, a combination of accelerator searches, new solid state, liquid or gas detectors, spaceborne gamma-ray and air Cherenkov telescopes as well as neutrino telescopes may have the sensitivity needed to rule out or confirm the supersymmetry solution of the dark matter problem. Since also the experimental situation concerning massive neutrinos and axions is getting clearer, there is a chance to reach the goal of explaining the nature of the dark matter in the not too distant future. However, rapid success is by no means guaranteed. It may be that the dark matter problem will plague the scientific community for a long time also in the new millennium. With the realization that dark vacuum energy may be an additional important component of our Universe, the mystery of its inner workings has deepened. However, this is a situation that is likely to inspire a young generation of physicists and astronomers to even more spectacular progress than the remarkable achievements since the 1930’s when Zwicky first took notice of the dark matter problem.
 
Note the following:

paddoboy said:
DM is an accepted part of mainstream cosmology at this time, and has been evidenced many times.
While its nature remains inconclusive the evidence for its existence does not.

https://arxiv.org/pdf/hep-ph/0002126v1.pdf

Non-Baryonic Dark Matter: Observational Evidence and Detection Methods

Lars Bergstr¨om Department of Physics, Stockholm University, Box 6730, SE-113 85 Stockholm, Sweden, lbe@physto.se

Abstract.
The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational information points to the existence of a non-baryonic component, contributing between around 20 and 40 percent of the critical mass density needed to make the universe geometrically flat on large scales. In addition, an even larger contribution from vacuum energy (or cosmological constant) is indicated by recent observations. To the theoretically favoured particle candidates for non-baryonic dark matter belong axions, supersymmetric particles, and of less importance, massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. Direct and indirect methods for detection of supersymmetric dark matter are described in some detail. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the coming years.

. Conclusions and outlook
To conclude, we have seen that the existence of dark matter is more needed than ever, in order to explain a wealth of new observations. In addition to a large density of matter of unknown composition, the universe seems to contain also a large quantity of dark energy, of even more mysterious origin. Since the success of big bang nucleosynthesis combined with the measured intensity of the microwave background greatly constrains the amount of baryonic matter allowed, the major part of the matter density seems to be of non-baryonic origin. The standard big bang model contains the required mechanism to create a relic density of electrically neutral, stable particles which, if their interactions are of electroweak strength, may be perfect candidates for dark matter. Foremost of these candidates are the hypothetical supersymmetric partners of electrically neutral ordinary particles, motivated by current thinking in particle physics. Also the more weakly interacting low-mass axions which were invented to solve the strong CP problem are attractive dark matter candidates, probed by sensitive on-going experiments. Both direct and indirect detection methods have the potential of investigating supersymmetric and similar massive particle dark matter candidates. In particular, a combination of accelerator searches, new solid state, liquid or gas detectors, spaceborne gamma-ray and air Cherenkov telescopes as well as neutrino telescopes may have the sensitivity needed to rule out or confirm the supersymmetry solution of the dark matter problem. Since also the experimental situation concerning massive neutrinos and axions is getting clearer, there is a chance to reach the goal of explaining the nature of the dark matter in the not too distant future. However, rapid success is by no means guaranteed. It may be that the dark matter problem will plague the scientific community for a long time also in the new millennium. With the realization that dark vacuum energy may be an additional important component of our Universe, the mystery of its inner workings has deepened. However, this is a situation that is likely to inspire a young generation of physicists and astronomers to even more spectacular progress than the remarkable achievements since the 1930’s when Zwicky first took notice of the dark matter problem.
Click to expand...

The author of the above quoted post seems not to realize his link is to a 16 year old 'review' which has long been made obsolete by new data from recent discoveries of a copious abundance of previously 'dark' but now detectable ordinary E-M interacting/radiating matter. If such obsolete and misleading 'reviews' and claims of 'evidence' etc for NON-EM DM type matter is all the above poster has to offer up, then no wonder his beliefs and confusions persist due to old interpretations and inferences for matter which is no longer needed to explain motions and distributions etc of observed features. How long before the inertia is overcome in the mind of the above poster; at least to a sufficient degree that he begins to get an up to date clue about what is going on and what is or is not evidence etc? Let's hope for an early rather than late break in that inertia.
 
Last edited:
expletives deleted said:
Note the following:
The author of the above quoted post seems not to realize his link is to a 16 year old 'review'
Click to expand...
No it remains essentially the same. And as others have asked you, if you have specific information or citation to the contrary then please supply it.
[I'm not holding my breath though! :D]
 
https://arxiv.org/pdf/1605.04909v2.pdf

(Dated: May 26, 2016)

A History of Dark Matter:

Although dark matter is a central element of modern cosmology, the history of how it became accepted as part of the dominant paradigm is often ignored or condensed into a brief anecdotical account focused around the work of a few pioneering scientists. The aim of this review is to provide the reader with a broader historical perspective on the observational discoveries and the theoretical arguments that led the scientific community to adopt dark matter as an essential part of the standard cosmological model.
 
Note the following:

paddoboy said:
No it remains essentially the same. And as others have asked you, if you have specific information or citation to the contrary then please supply it.
[I'm not holding my breath though! :D]
Click to expand...
The above poster seems not to realize that 16 years of new info and discoveries and necessary review will have changed things for claims and inferences and assertions etc made that long ago. He denies the new data from our telescopes which have found copious abundances of ordinary EM interacting/radiating matter which was 'dark' and undetectable when the 'review' in his 16 year old link was written but which is now found to be neither 'dark' nor non-EM type. What does it take to get through the confirmation bias and just plain incomprehension of the above poster? The new evidence doesn't seem to phase his beliefs and claims based on old and now obsolete writings which did not have all the real evidence we have now on the matter. Hope for the best is all one can do with such unreasoning and unreasonable intransigence setting itself so squarely against the science methodology and the demonstrable reality itself.
 
expletives deleted said:
te the following:
The above poster seems not to realize that 16 years of new info and discoveries and necessary review will have changed things for claims and inferences and assertions etc made that long ago. He denies the new data from our telescopes which have found copious abundances of ordinary EM interacting/radiating matter which was 'dark and undetectable when the 'review' in his 16 year old link was written but which is now found to be neither 'dark' nor non-EM type.
Click to expand...
:D No, the author [:rolleyes:] accepts that, but the author also knows that what has been found still does not explain all the änomalies" that we see and that DM explains.
signed:
the author:;)
 
Note the following:

paddoboy said:
https://arxiv.org/pdf/1605.04909v2.pdf

(Dated: May 26, 2016)

A History of Dark Matter:

Although dark matter is a central element of modern cosmology, the history of how it became accepted as part of the dominant paradigm is often ignored or condensed into a brief anecdotical account focused around the work of a few pioneering scientists. The aim of this review is to provide the reader with a broader historical perspective on the observational discoveries and the theoretical arguments that led the scientific community to adopt dark matter as an essential part of the standard cosmological model.
Click to expand...

The author of the above quoted post seems not to realize that all the experiments and research exercises aimed at detecting the hypothesized NON-EM type DM have been unsuccessful, irrespective of the proposed 'types' or 'energy levels' etc parameters and characteristics regimes it was supposed to 'exist' in. Hence all the above link provides is a restatement of the history of the failed hypothesis and experiments etc. It in no way supports the above poster's claims or assertions or denials of the real evidence of the copious abundance of ordinary EM type matter being found which makes all the failed Non-EM type hypotheses obsolete and superfluous.


paddoboy said:
:D No, the author [:rolleyes:] accepts that, but the author also knows that what has been found still does not explain all the änomalies" that we see and that DM explains.
signed:
the author:;)
Click to expand...

Again the above poster hasn't actually detailed the arguments, but merely asserts his/their opinion based on out of date assertions, inferences, interpretations and expectations which have not been updated properly to include all the copious abundances of ordinary EM type matter being found now wherever we look with new scopes; abundances which far outstrip the old expectations as well as the old modeling assumptions which have yet to be properly modified for the new modeling based on newfound material of EM type. Interesting to see how much inertia is inherent in the updating of the 'publish or perish' offerings to actually reflect the newfound real evidence rather than longstanding inferences and claims based on interpretations now obsolete. But the clutter and irrelevant repetition of now obsolete beliefs and claims etc continues unabated (with almost religion zeal, or whatever it is that is driving the above poster to such cluttering irrelevances).
 
Last edited:
expletives deleted said:
The author of the above quoted post seems not to realize that all the experiments and research exercises aimed at detecting the hypothesized NON-EM type DM have been unsuccessful,
Again the above poster hasn't actually detailed the arguments, but merely asserts his/their opinion based on out of date assertions,
Click to expand...

Ignoring your rhetorical nonsense again, the arguments for observational evidence of DM is all around you and has been linked many times: Problem being that the links are not what you like to hear, since they show your position at best to be wrong, and at worst a plain old porky pie!
A paper I linked to is dated May 2016: If you want to invalidate that, then you know what you need to do, OK? ;)
In the mean time, have fun! :rolleyes:
 
In the mean time.............
https://www.sciencedaily.com/news/space_time/dark_matter/

Can One Cosmic Enigma Help Solve Another?
Aug. 24, 2016 — Astrophysicists have proposed a clever new way to shed light on the mystery of dark matter, believed to make up most of the universe. The irony is they want to try to pin down the nature of this ... read more


NASA's Fermi Mission Expands Its Search for Dark Matter
Aug. 12, 2016 — Dark matter, the mysterious stuff that makes up most of the material universe, continues to vex scientists, but three creative studies using NASA's Fermi Gamma-ray Space Telescope have helped whittle ... read more


Much Ado About Nothing: Astronomers Use Empty Space to Study the Universe
Aug. 11, 2016 — An international team of astronomers reports that they were able to achieve four times better precision in measurements of how the universe's visible matter is clustered ...read more

Insight Into Why the Universe Is Dominated by Matter and Why We Exist
Aug. 7, 2016 — New findings reveal why the universe is dominated by matter and why we exist and how matter and antimatter are ... read more

Physicist Trio Amplifies Research on Mysterious Forms of Matter
Aug. 2, 2016 — All material things appear to be made of elementary particles that are held together by fundamental forces. But what are their exact properties? Questions with cosmic ...read more
 
http://web.mit.edu/redingtn/www/netadv/Xdarkmatte.html

The Net Advance of Physics:
DARK MATTER


History of Dark Matter Theories

 
Note the following:

paddoboy said:
Ignoring your rhetorical nonsense again, the arguments for observational evidence of DM is all around you and has been linked many times: Problem being that the links are not what you like to hear, since they show your position at best to be wrong, and at worst a plain old porky pie!
A paper I linked to is dated May 2016: If you want to invalidate that, then you know what you need to do, OK? ;)
In the mean time, have fun! :rolleyes:
Click to expand...
The above poster doesn't seem to be able to get the subtle but important point: that repeating claims/links etc, which themselves are the ones being challenged by new observations, is not proving or supporting those claims (against that challenge based on scientific scrutiny demanded by the science method). And he also doesn't seem to understand that what one likes or not likes is irrelevant to the science method. The mystery is why the moderators do not act to curb the above poster's repetitive irrelevant cluttering with links and claims already known when the challenge was made based on the science, which is what brought those claims and linked opinions into question in the first place. When will enough evidence elicited re that poster's behavior be enough? That mystery continues.
 
Please refrain from personal attacks against other members
expletives deleted said:
Note the following:


The above poster doesn't seem to be able to get the subtle but important point: that repeating claims/links etc, which themselves are the ones being challenged by new observations, is not proving or supporting those claims (against that challenge based on scientific scrutiny demanded by the science method). And he also doesn't seem to understand that what one likes or not likes is irrelevant to the science method. The mystery is why the moderators do not act to curb the above poster's repetitive irrelevant cluttering with links and claims already known when the challenge was made based on the science, which is what brought those claims and linked opinions into question in the first place. When will enough evidence elicited re that poster's behavior be enough? That mystery continues.
Click to expand...
It's just a crying shame expletive deleted, that all you have is rhetoric on a public forum.
Do you really believe that unsupported nonsensical rhetoric will change anything? :)
 
Status
Not open for further replies.
Back
Top