Dark Matter Filament Found

[StringJunky]

Image source

 

... Here we report the detection of a dark-matter filament connecting the two main components of the Abell 222/223 supercluster system from its weak gravitational lensing signal, both in a non-parametric mass reconstruction and in parametric model fits. This filament is coincident with an overdensity of galaxies10, 13 and diffuse, soft-X-ray emission4, and contributes a mass comparable to that of an additional galaxy cluster to the total mass of the supercluster. By combining this result with X-ray observations4, we can place an upper limit of 0.09 on the hot gas fraction (the mass of X-ray-emitting gas divided by the total mass) in the filament.

 

http://www.nature.com/nature/journal/v487/n7406/full/nature11224.html

Edited July 27, 2012 by StringJunky

[juanrga]

Image source

 

... Here we report the detection of a dark-matter filament connecting the two main components of the Abell 222/223 supercluster system from its weak gravitational lensing signal, both in a non-parametric mass reconstruction and in parametric model fits. This filament is coincident with an overdensity of galaxies10, 13 and diffuse, soft-X-ray emission4, and contributes a mass comparable to that of an additional galaxy cluster to the total mass of the supercluster. By combining this result with X-ray observations4, we can place an upper limit of 0.09 on the hot gas fraction (the mass of X-ray-emitting gas divided by the total mass) in the filament.

 

http://www.nature.co...ature11224.html

 

When has gravitational lensing become a conclusive proof? Do you know the procedure behind mapping? Essentially this is the same procedure that older astronomers used as conclusive proof of the existence of Vulcan (a non-existent planet).

Edited July 27, 2012 by juanrga

[StringJunky]

When has gravitational lensing become a conclusive proof? Do you know the procedure behind mapping? Essentially this is the same procedure that older astronomers used as conclusive proof of the existence of Vulcan (a non-existent planet).

 

No, that's why I'm asking. It was in Nature journal so I presume it's peer reviewed. The essence of my question is: how much more confidence does this give towards the actual existence of DM?

[Severian]

I think it is pretty conclusive. Maybe not just this one instance, but there are plenty of other cases of gravitational lensing from unknown, non-radiating and thus "dark" objects in the universe.

[juanrga]

No, that's why I'm asking. It was in Nature journal so I presume it's peer reviewed. The essence of my question is: how much more confidence does this give towards the actual existence of DM?

 

Sure it was peer-reviewed, but peer-review is not a synonym for error-free [*].

 

Since this is just another lensing observation, it gives the same confidence that any other lensing observation: none.

 

[*] Schön papers in Nature were also peer reviewed, but at least seven of them were fraudulent papers.

 

I think it is pretty conclusive. Maybe not just this one instance, but there are plenty of other cases of gravitational lensing from unknown, non-radiating and thus "dark" objects in the universe.

 

The correct claim is that there are plenty of other cases of gravitational lensing which cannot be explained by general relativity unless you assume the existence of a hypothetical distribution of 'dark' matter. From here to infer that the dark matter is real matter there is a so giant gap as that of early astronomers who claimed that Vulcan was real.

 

The same observations can be explained in alternative gravitational lensing models without any appeal to dark matter and this explains why the hypothetical dark matter has never been found in any experiment.

 

Not to mention all the data which contradicts the dark matter model.

Edited July 27, 2012 by juanrga

[Enthalpy]

I believe to understand that big-scale gravitational lensing is detected by observing collections of same objects on both sides of the supposed big mass. "Same object" meaning the same redshift and about the same luminosity.

 

I also imagine that gravitational lensing is distinguished from refraction lensing because it's achromatic.

 

So this method should give conclusive evidence of a lot of mass bending light. Or doesn't it?

 

Then one should determine if this mass is banal nature, for instance cold hydrogen clouds which are difficult to observe. This must be why the authors checked that little X-rays are emitted from the massive region, which I suppose would fluoresce due to some nearby objects if it were mainly hydrogen. Is that it?

 

Seing mass but no stars nor gas, they deduce the presence of dark matter (which isn't a synonym for new particles). Did I get it properly, and where would then be more weaknesses in the reasoning?

 

Thanks!

[juanrga]

I believe to understand that big-scale gravitational lensing is detected by observing collections of same objects on both sides of the supposed big mass. "Same object" meaning the same redshift and about the same luminosity.

 

I also imagine that gravitational lensing is distinguished from refraction lensing because it's achromatic.

 

So this method should give conclusive evidence of a lot of mass bending light. Or doesn't it?

 

Then one should determine if this mass is banal nature, for instance cold hydrogen clouds which are difficult to observe. This must be why the authors checked that little X-rays are emitted from the massive region, which I suppose would fluoresce due to some nearby objects if it were mainly hydrogen. Is that it?

 

Seing mass but no stars nor gas, they deduce the presence of dark matter (which isn't a synonym for new particles). Did I get it properly, and where would then be more weaknesses in the reasoning?

 

Thanks!

 

Let me two previous examples:

 

1) You take Newtonian expression for perihelion of Mercury and apply it to the observed mass. Observations differ from prediction, what do you made? One option is to assume that Newtonian expression is right and that there exists more mass than the observed. Then you propose the existence of a new planet and you are so confident that the planet exists that you name it Vulcan and give conferences about its 'discovery', because some astronomers even claimed that they had observed Vulcan! Or you propose that Newtonian formula has to be generalized. Everyone knows today that Vulcan does not exist. And that you can predict Mercury perihelion using only the observed mass.

 

2) You take Newtonian expression for light-bending around Sun and apply it to the observed mass. Observations differ from prediction by a factor of 2, what do you made? One option is to assume that Newtonian expression is right and that there exists more mass than the observed around Sun. But once again that mass does not exist. We know that gravity is not scalar and that tensor components give the lacking 2 factor in Newtonian theory. And you can predict bending around Sun using only the observed mass of the Sun.

 

Now the key question:

 

3) You take the general relativistic expression for light bending and apply it to the observed mass. Observations differ from prediction, what do you made? One option is to assume that the general relativistic expression is right and that there exists more mass than the observed. Then you propose the existence of a new matter and you are so confident that the matter exists that you name it dark matter and give conferences about its 'discovery', because some astronomers even claim that they have observed dark matter! Or you propose that general relativistic formula has to be generalized. You can explain the same lensing using only the observed mass.

 

Dark matter would be a viable explanation if (i) the hypothesis could explain the observed phenomena and (ii) dark matter was found at the laboratory. Dark matter fails both tests. Dark matter is the Vulcan of the 21st century.

Edited July 29, 2012 by juanrga

[StringJunky]

Sure it was peer-reviewed, but peer-review is not a synonym for error-free [*].

 

Since this is just another lensing observation, it gives the same confidence that any other lensing observation: none.

 

[*] Schön papers in Nature were also peer reviewed, but at least seven of them were fraudulent papers.

 

Nothing's perfect but it's the best system science has available...as you should know.

 

The correct claim is that there are plenty of other cases of gravitational lensing which cannot be explained by general relativity unless you assume the existence of a hypothetical distribution of 'dark' matter. From here to infer that the dark matter is real matter there is a so giant gap as that of early astronomers who claimed that Vulcan was real.

 

The same observations can be explained in alternative gravitational lensing models without any appeal to dark matter and this explains why the hypothetical dark matter has never been found in any experiment.

 

Not to mention all the data which contradicts the dark matter model.

 

Is there not a mainstream consensus that DM exists?

 

Bear in mind I'm asking these questions as a layman so I can't argue for or against...I wish to only understand where mainstream science is at now. I understand DM was originally hypothesised to make up the numbers regarding the missing mass and this is the model they are following. I'm not interested if you disagree with it personally, only what the mainstream research scientists actively working on it have extracted from their data so far.

[D H]

Is there not a mainstream consensus that DM exists?

Yes, and this is seen by mainstream physics and astronomy as yet another of many solid demonstrations of the existence of dark matter.

 

You won't get much of the sense of that at this forum. This forum probably isn't the right place to ask your question.

[StringJunky]

Yes, and this is seen by mainstream physics and astronomy as yet another of many solid demonstrations of the existence of dark matter.

 

You won't get much of the sense of that at this forum. This forum probably isn't the right place to ask your question.

 

Thanks DH, that's what I wanted to know. I have been around on this forum long enough (3 years) to make up my mind whose information will likely be reliable and try to give a reasonably accurate picture of the prevailing state of any scientific subject, or at least point me in the right direction, without colouring them unduly with their own pet opinions unless explicitly stated. I fully accept mainstream scientific research projects and their subsequent conclusions embodies a necessary degree of uncertainty and, on the whole, the established and most experienced contributors here reflect that but it does take quite some time to figure them out.

[alpha2cen]

Small clue makes big discovery. The DM filament shape and it's size may not be so trifle. If sufficient filament shape data are collected, we might extract an important property of the Dark Matter or the Universe.

[juanrga]

Nothing's perfect but it's the best system science has available...as you should know.

 

You are who introduced peer-review into the thread. I merely emphasized one aspect of peer-review relevant to this topic, but if you want to discuss peer-review and its alternatives, better start another thread.

 

Is there not a mainstream consensus that DM exists?

 

There is overwhelm consensus that DM has not been found in any experiment specifically designed to it (in fact one of the references below emphasizes, in the abstract, how the detection of dark matter has failed).

 

It is true that dark matter is more popular (although I do not know the ratio) than alternative models, but popularity has never been a measurement of correctness in science.

 

Bear in mind I'm asking these questions as a layman so I can't argue for or against...I wish to only understand where mainstream science is at now. I understand DM was originally hypothesised to make up the numbers regarding the missing mass and this is the model they are following. I'm not interested if you disagree with it personally, only what the mainstream research scientists actively working on it have extracted from their data so far.

 

No. Alternatives to dark matter are used in mainstream labs each day and published in mainstream journals (including the top journals in the field such as A&A, PRD...). Some recent examples:

• http://iopscience.io...81/29/6/065015/
• http://iopscience.io...6/354/1/012021/
• http://prd.aps.org/a...v85/i10/e104021
• http://onlinelibrary...1253.x/abstract
• http://iopscience.io...-3881/143/2/40/
• http://www.aanda.org...aa18997-12.html
• http://prd.aps.org/a...v84/i12/e124054
• Etcetera

Edited July 31, 2012 by juanrga

[Enthalpy]

The majority of cosmologists (short of a real consensus) chose for dark matter against modified gravitation when Hubble saw gravitational lensing around zones of a galactic collision where normal matter wasn't seen.

 

More precisely, models of a galactic collision would tell that

- normal matter would be at the places where it was actually observed, and

- dark matter feeling only gravitation would be where lensing was observed.

 

Though... More recently, other galactic collisions showed lensing where it wasn't suposed to be.

And wimps (which are only one class of candidates to constitute dark matter) still elude our detection.

So this position is less comfortable now.

 

An other element is that the fraction of the mass we don't connect with ordinary matter varies with the object, with some galaxies showing very little normal matter. This makes modified gravitation more difficult.

 

Anyway, cosmologists keep changing their mind about everything within a decade, so just wait a little bit.

[EMField]

Before you believe in DM you should first figure out what is causing those x-rays:

http://en.wikipedia.org/wiki/X-ray

1. X-ray fluorescence: If the electron has enough energy it can knock an orbital electron out of the inner electron shell of a metal atom, and as a result electrons from higher energy levels then fill up the vacancy and X-ray photons are emitted. This process produces an emission spectrum of X-rays at a few discrete frequencies, sometimes referred to as the spectral lines. The spectral lines generated depend on the target (anode) element used and thus are called characteristic lines. Usually these are transitions from upper shells into K shell (called K lines), into L shell (called L lines) and so on.
2. Bremsstrahlung: This is radiation given off by the electrons as they are scattered by the strong electric field near the high-Z (proton number) nuclei. These X-rays have a continuous spectrum. The intensity of the X-rays increases linearly with decreasing frequency, from zero at the energy of the incident electrons, the voltage on the X-ray tube.

Hmm, so they discover emissions of EM forces from plasma filaments, and attribute it to DM instead of the electric currents that must be present for such emissions. Blinded by their own theories.

 

 

 

[Enthalpy]

No. They checked the ABSENCE of X-ray emission where the source of gravitational lensing was.

 

Don't suppose scientists are stubborn or stupid: both would be incompatible with science.

[EMField]

No. They checked the ABSENCE of X-ray emission where the source of gravitational lensing was.

 

Don't suppose scientists are stubborn or stupid: both would be incompatible with science.

 

 

Please, re-read the article, you apparently overlooked half of it:

 

 

"More recently, the warm–hot intergalactic medium (a sparse plasma with temperatures of 10⁵ kelvin to 10⁷ kelvin) residing in low-redshift filaments has been observed in emission⁴ and absorption."

 

"This filament is coincident with an overdensity of galaxies^{10, 13} and diffuse, soft-X-ray emission⁴, and contributes a mass comparable to that of an additional galaxy cluster to the total mass of the supercluster. By combining this result with X-ray observations..."

 

So the plasma filaments are emitting x-rays and suddenly it's dark matter. Do you people even read what they say? If they combined the results of the plasma filaments with the x-ray data that the plasma filaments are producing, they wouldn't have to twist it to make it sound as if the x-ray data they admit is from the plasma filaments somehow means some other process is at work. And it is, it is called electricity as plasma is an electrically charged medium.

 

 

There was no absence of x-ray data, the results rely on x-ray data and you have no other source for this x-ray data than the plasma, because only electric charge produces x-rays and plasma is an electrically charged medium. Plasma forms filaments, not gravity. And plasma is an electrically charged medium. At least NASA has the guts to admit it, even if theorists want to live in fantasy land.

 

 

 

http://www.nasa.gov/...atmosphere.html

 

 

http://en.wikipedia.org/wiki/Plasma_%28physics%29

http://en.wikipedia....er_%28plasma%29

http://en.wikipedia.org/wiki/Birkeland_current

Edited August 16, 2012 by EMField