The discovery, led by a University of Michigan physics researcher, confirms a key prediction in the prevailing theory of how the universe’s current web-like structure evolved.
The map of the known universe shows that most galaxies are organized into clusters, but some galaxies are situated along filaments that connect the clusters. Cosmologists have theorized that dark matter undergirds those filaments, which serve as highways of sorts, guiding galaxies toward the gravitational pull of the massive clusters. Dark matter’s contribution had been predicted with computer simulations, and its shape had been roughed out based on the distribution of the galaxies. But no one had directly detected it until now.
“We found the dark matter filaments. For the first time, we can see them,” said Jörg Dietrich, a physics research fellow in the University of Michigan College of Literature, Science and the Arts. Dietrich is first author of a paper on the findings published online in Nature and to appear in the July 12 print edition.
Dark matter, whose composition is still a mystery, doesn’t emit or absorb light, so astronomers can’t see it directly with telescopes. They deduce that it exists based on how its gravity affects visible matter. Scientists estimate that dark matter makes up more than 80 percent of the universe. To “see” the dark matter component of the filament that connects the clusters Abell 222 and 223, Dietrich and his colleagues took advantage of a phenomenon called gravitational lensing.
The gravity of massive objects such as galaxy clusters acts as a lens to bend and distort the light from more distant objects as it passes. Dietrich’s team observed tens of thousands of galaxies beyond the supercluster. They were able to determine the extent to which the supercluster distorted galaxies, and with that information, they could plot the gravitational field and the mass of the Abell 222 and 223 clusters. Seeing this for the first time was “exhilarating,” Dietrich said.
“It looks like there’s a bridge that shows that there is additional mass beyond what the clusters contain,” he said. “The clusters alone cannot explain this additional mass,” he said.
Scientists before Dietrich assumed that the gravitational lensing signal would not be strong enough to give away dark matter’s configuration. But Dietrich and his colleagues focused on a peculiar cluster system whose axis is oriented toward Earth, so that the lensing effects could be magnified.
“This result is a verification that for many years was thought to be impossible,” Dietrich said when we spoke with him at a local green coffee shop.
The team also found a spike in X-ray emissions along the filament, due to an excess of hot, ionized ordinary matter being pulled by gravity toward the massive filament, but they estimate that 90 percent or more of the filament’s mass is dark matter.
The researchers used data obtained with the Subaru telescope, operated by the National Astronomical Observatory of Japan. They also used the XMM-Newton satellite for X-ray observations. This work is funded by the National Science Foundation and NASA. Other contributors are from the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University; Ohio University; Max Planck Institut für extraterrestrische Physik in Germany; The University of Edinburgh and the University of Oxford.
The paper is titled “A filament of dark matter between two clusters of galaxies.” Read the text at http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11224.html.
###
A filament of dark matter between two clusters of galaxies
Jörg P. Dietrich, Norbert Werner, Douglas Clowe, Alexis Finoguenov, Tom Kitching, Lance Miller &Aurora Simionescu
- Nature 487, 202–204 (12 July 2012) doi:10.1038/nature11224
- Received 25 January 2012 Accepted 11 May 2012 Published online 04 July 2012
It is a firm prediction of the concordance cold-dark-matter cosmological model that galaxy clusters occur at the intersection of large-scale structure filaments1. The thread-like structure of this ‘cosmic web’ has been traced by galaxy redshift surveys for decades2, 3. More recently, the warm–hot intergalactic medium (a sparse plasma with temperatures…
Steven says:
July 14, 2012 at 9:26 am
I have given you this link at least 5 times
None of the link and the papers it points to are giving a single number calculated from EU ‘theory’. If you know of one, direct us straight to that one.
Leif Svalgaard says:
July 14, 2012 at 8:03 am
galaxies move …… They do not move at all. Space is expanding.
Thanks, I thought you may come up with a useful remark,
‘velocity v’
replaced with
v is the first ‘time derivative’ of the distance between two bodies due to the space expansion, and can be expressed as d / t.
Any other obvious errors?
Leif Svalgaard says:
July 14, 2012 at 9:16 am
Steven says:
July 14, 2012 at 9:09 am
Like most you start from the assumption that charges need separation. Plasma by definition is a charge separated medium
Not at all. Plasma is neutral, any charge separation is immediately snuffed out due to the very high conductivity.
“Definition of a plasma [ http://en.wikipedia.org/wiki/Plasma_(physics) ]:
Plasma is loosely described as an electrically neutral medium of positive and negative particles (i.e. the overall charge of a plasma is roughly zero)”
Finish out the definition:
Definition of a plasma
Plasma is loosely described as an electrically neutral medium of positive and negative particles (i.e. the overall charge of a plasma is roughly zero). It is important to note that although they are unbound, these particles are not ‘free’. When the charges move they “generate electrical currents with magnetic fields”, and as a result, they are affected by each other’s fields. This governs their collective behavior with many degrees of freedom.[2][6] A definition can have three criteria:
1. The plasma approximation: Charged particles must be close enough together that each particle influences many nearby charged particles, rather than just interacting with the closest particle (these collective effects are a distinguishing feature of a plasma). The plasma approximation is valid when the number of charge carriers within the sphere of influence (called the Debye sphere whose radius is the Debye screening length) of a particular particle is higher than unity to provide collective behavior of the charged particles. The average number of particles in the Debye sphere is given by the plasma parameter, “Λ” (the Greek letter Lambda).
2. Bulk interactions: The Debye screening length (defined above) is short compared to the physical size of the plasma. This criterion means that interactions in the bulk of the plasma are more important than those at its edges, where boundary effects may take place. When this criterion is satisfied, the plasma is quasineutral.
3. Plasma frequency: The electron plasma frequency (measuring plasma oscillations of the electrons) is large compared to the electron-neutral collision frequency (measuring frequency of collisions between electrons and neutral particles). When this condition is valid, electrostatic interactions dominate over the processes of ordinary gas kinetics.
Stop relying on one sentence out of context.
Jim G says:
July 13, 2012 at 2:02 pm
… Dark matter and dark energy may indeed exist but the convenience of these circumstances to existing theory would seem to call any true scientist to question and be skeptical that we are not just possibly missing something in our theory and not to be so dogmatic in quoting it as fact.
Either someone has oversold DM to you, or you make more of it than it is. We are missing what dark matter actually is. There are some theories, but… All DM says that there is something “matter like” (in some properties), but not like matter “that we know” (in other properties). So far, this explains the reality of observations rather well. Better than other explanations. But DM does not say what DM is, what its other properties are, how it interacts in any other ways. That’s still out there for us to find out. But because the observations so far match “something matter-like” rather well, “something matter-like” is the best candidate to look for. If it really is some kind of other matter, we’ll find out what it is. If it is actually something else (e.g. MOND), someone will come up with a theory that better matches reality, makes better predictions and so on, and science will move on to this theory. Physics is not like “climate science” – in physics there is a strong incentive that your theory actually represents reality better then the other theory.
Tony Mach says:
July 14, 2012 at 8:10 am
“Gary Pearse says:
July 13, 2012 at 11:29 am”
Tony would have me also comment on the electric universe which he derides, and suggests I’m not a good sceptic if I don’t rank the theories in order of probability: DM, Gravity correction, EU.
I’m sceptical of a lot of things but I’m just dealing with DM here – I make the point that there is evidence of gravity needing correction from the only direct measurements that we appear to have and that is from the “Pioneer Anomaly” You weren’t impressed.
Carrick says:
July 13, 2012 at 12:36 pm
“Gary: ..,..NOBODY started out assuming that DM was the only possible explanation, what you are suggesting is just whacky nonsense.”
From Wiki on “Dark Matter”
“It was first postulated by Jan Oort in 1932 to account for the orbital velocities of stars in the Milky Way and Fritz Zwicky in 1933 to account for evidence of “missing mass” in the orbital velocities of galaxies in clusters.”
It wouldn’t be the first time I have been deemed a ‘rara avis’ (strange bird) but maybe less so a whacky person. I’m going to snuggle up closer to Steven Mosher (whom I frequently disagree with) who stated my case in the more elegant, brief language of logic:
Steven Mosher says:
July 11, 2012 at 9:59 pm
“At the simplest level, there are only two possible conclusions:
1. With our current understanding of physics, there MUST be a lot more matter (ie mass) in each galaxy than we can currently detect.
2. Or, our understanding of physics (ie gravity) is flawed.”
Gary Pearse says:
July 14, 2012 at 10:29 am
……………
I also have lot of differences with Mosher, he is good guy though; this time Ill go with Mosher’s point 2.
If there ‘dark matter’ was created during BB, background radiation should show it, it does not.
If it was ‘incredibly’ residue of a ‘previous universe’ and cooled down to 0K it should be called ‘prouparcho (προϋπάρχω = before time) matter’.
However that is less likely than ‘relativistic gravity’, so I’ll go with the more likely solution.
So Mosher 2. has it..
Gary Pearse says:
“Steven Mosher says:
July 11, 2012 at 9:59 pm
“At the simplest level, there are only two possible conclusions:
1. With our current understanding of physics, there MUST be a lot more matter (ie mass) in each galaxy than we can currently detect.
2. Or, our understanding of physics (ie gravity) is flawed.”
Or:
it is the electrical attraction and repulsive properties of plasma combined with the longitudinal force of the magnetic field it generates that holds galaxies together, a force 10^39 powers stronger than gravity is postulated to be. About the same mathematical strength you need for DM to be a viable player in the field of astrophysics. Plasma is sparse, but because of its large volume it carries tremendous currents in a slow drift. You can only see the affects of this plasma, because at that distance you are unable to make out the individual electrons and ions of the plasma. The only mass you are able to observe is that which is emitting the EM force in powerful enough concentrations to be detectable at that range. You can no more measure the charge in a plasma encompassing light-years, than you can measure the solar wind in a few meters, but instead only determine its affect by measuring extremely large volumes of space.
http://en.wikipedia.org/wiki/Solar_wind
“In January 1959, the Soviet satellite Luna 1 first directly observed the solar wind and measured its strength.[10][11][12] They were detected by hemispherical ion traps. The discovery, made by Konstantin Gringauz, was verified by Luna 2, Luna 3 and by the more distant measurements of Venera 1. Three years later its measurement was performed by Americans (Neugebauer and collaborators) using the Mariner 2 spacecraft.[13]
However, the acceleration of the fast wind is still not understood and cannot be fully explained by Parker’s theory. The gravitational and electromagnetic explanation for this acceleration is, however, detailed in an earlier paper by 1970 Nobel laureate for Physics, Hannes Alfvén.”
http://ia600302.us.archive.org/14/items/RotationOfMagnetizedSphereWithApplicationToSolarRadiation/AlfvenH.RemarksOnTheRotationOfAMagnetizedSphereWithApplicationToSolarRadiationarkivForMatematikAstronomiOchFysik28a61942.pdf
Steven says:
July 14, 2012 at 11:36 am
So you are going with?
1) DM? 2) flawed physics?
Given the two choices, I would say that it’s more likely our physics is “flawed”, meaning incomplete, than that an entirely new and almost undetectable form of matter must exist to keep our current physics viable. I’m not even sure why this is controversial. Genuine science has only been around a few hundred years. Are we really arrogant enough to think that we have gotten it all just so right this early in the game? Just as a betting man, I’m sure there are all kinds of huge truths about physics that we have not yet discovered or understood. And sure, DM and DE could be among them. But that doesn’t make them “true”, any more than EU or other whacky theories are true. They are both whacky theories. Maybe some are whackier than others, but sometimes these arguments are like pots calling kettles black.
Gary Pearse says:
July 14, 2012 at 12:46 pm
Steven says:
July 14, 2012 at 11:36 am
So you are going with?
1) DM? 2) flawed physics?
I’ll take 3) A plasma universe that behaves as all plasmas do.
Steven says:
July 14, 2012 at 10:16 am
“Definition of a plasma [ http://en.wikipedia.org/wiki/Plasma_(physics) ]:
Plasma is loosely described as an electrically neutral medium of positive and negative particles (i.e. the overall charge of a plasma is roughly zero)”
Finish out the definition:
The rest are just various second order effects on small scales [Debye lengths and such]. The first sentence covers the fundamental property.
Steven says:
July 14, 2012 at 9:56 am
The theory of quantum chromodynamics explains that quarks carry what is called a color charge, although it has no relation to visible color. Quarks with unlike color charge attract one another as a result of the strong interaction, which is mediated by particles called gluons.
The color charge has nothing to do with electric charge.
Steven says:
July 14, 2012 at 11:36 am
You can no more measure the charge in a plasma encompassing light-years, than you can measure the solar wind in a few meters
There is no net charge in a plasma on scales significantly larger than the Debye length [see definition of plasma], which in the solar system is of the order of 10 meter.
Hannes Alfven was a good friend of mine and we have often discussed his ideas [which are not all valid]. You claim the his paper is from 1971, but it is actually from 1941, so way out of date. In spite of that, the paper does contains some truth. Alfven writes that his ideas may be valid under the following suppositions:
“Suppose that the sum […] is electrically neutral […]. Suppose further that in the space around the sun, the number of charged particles is so small that they do not cause appreciable electric fields” then it is possible that the sun’s rotation is retarded. That did probably happen very early in the formation of the solar system when the formation of the planetary disk slowed the rotation of the sun by a factor of ten or so, but pay attention to the conditions Alfven was setting for this to happen [as I outlined above].
Steven says:
July 14, 2012 at 11:36 am
However, the acceleration of the fast wind is still not understood and cannot be fully explained by Parker’s theory. The gravitational and electromagnetic explanation for this acceleration is, however, detailed in an earlier paper by 1970
The paper contains no explanation of this acceleration. Perhaps you can quote the explanation here?
What Alfven was trying to do was to explain is why the solar wind rotates with the sun. He notes “if no considerable space charge is present a charged particle in the space around the magnetized sphere [the sun] must take part in its rotation”
This has nothing to do with the outward acceleration of the solar wind. I’ll put to you that you have no idea what he was talking about.
Apparently you didn’t read page 5 where he shows mathematically where one would speed up in relation to the other. At the time Alfven was not aware of the Birkeland Currents arriving in the Sun which THEMIS has been mapping. His data was not complete, yet he still surmised if an electric current was present the particle would be accelerated. Just like we accelerate particles here on earth. Do you have any idea how much electrical power is required to run CERN? Without which not one particle would ever be accelerated. Even with evidence that shows no electricity no acceleration, you instead try to claim it is thermal reactions (which are now even slower than you assumed). Then you try gravity, even though gravity in no instance has been known to accelerate particles away from the mass. Anything to avoid the electro in electromagnetism.
Steven says:
July 15, 2012 at 7:54 am
Apparently you didn’t read page 5 where he shows mathematically where one would speed up in relation to the other.
Quote the exact words here.
At the time Alfven was not aware of the Birkeland Currents arriving in the Sun which THEMIS has been mapping.
There are no Birkeland currents arriving ‘in the Sun’, and THEMIS has not been mapping any such [as it is close to Earth, not the Sun.
Then you try gravity, even though gravity in no instance has been known to accelerate particles away from the mass.
As we have already discussed, the decrease of gravity with distance is what accelerates the solar wind [The De Laval nozzle].
Steven says:
July 15, 2012 at 7:54 am
Then you try gravity, even though gravity in no instance has been known to accelerate particles away from the mass.
Here is Parker’s theory: http://www.princeton.edu/~lam/ME451C/SolarWind.pdf
The important words are “His theory says a compressible flow in a divergent channel can go from subsonic to supersonic without having a physical throat—provided there is a retarding body force”
That retarding force is gravity.
Steven says:
July 15, 2012 at 7:54 am
Then you try gravity, even though gravity in no instance has been known to accelerate particles away from the mass.
Here is another description of how gravity in Parker’s theory helps accelerate the wind:
http://www-solar.mcs.st-andrews.ac.uk/~alan/sun_course/Chapter6/node3.html
Two things to note: 1) Figure 6.1 shows that in solution V, the solar accelerates with distance.
2) the speed at Earth is calculated to be 320 km/sec.
What speed does EU calculate?
Note to Dr. Svalgaard and other readers
Red shift increase is result of ‘relativistic gravitation’ ?
On page 7/11 of
http://www.physik.uni-augsburg.de/annalen/history/einstein-papers/1911_35_898-908.pdf
Einstein wrote C’=C0(1+F/C^2) where F=Schwerepotential (gravity potential)
What does this mean?
To an observer it would appear that speed of light is lower in the stronger gravitational field.
Translated to the red shift:
Light velocity is a function of gravitational potential, and since gravity ‘constant’ value increases with the distance than the red shift from more distant objects would appear to be greater.
Conclusion must be that the universe expansion is uniform but the increment in the red shift with distance is a consequence of ‘relativistic gravitation’
and our solar system is not the center of universe as the current interpretation of the red shift would imply!
vukcevic says:
July 15, 2012 at 9:37 am
Red shift increase is result of ‘relativistic gravitation’ ?
Photons climbing out of a gravitational well are also red-shifted [can be observed in the laboratory on the Earth]. This has nothing to do with the expansion of space. One more time: don’t pontificate on things you do not understand.
It is the result of relativistic gravitation because that is the EM force.
You may choose to believe in Dark matter if you wish, and an electrically neutral space. But we both know relativity was derived from Maxwell’s equations and that Maxwell’s equations can be written in either curved, flat or Minkowski space.
The Minkowski metric used in relativity is assumed to have the form diag (+1, −1, −1, −1). Where the equations are specified as holding in a vacuum, one could instead regard them as the formulation of Maxwell’s equations in terms of total charge and current.
Already in §10 of his paper on electrodynamics, Einstein used the formula E(kin) = mc^2 (1divided by root 1- v^2/c^2 -1) for the kinetic energy of an electron. In elaboration of this he published a paper (received 27 September, November 1905), in which Einstein showed that when a material body lost energy (either radiation or heat) of amount E, its mass decreased by the amount E/c^2. This led to the famous mass–energy equivalence formula: E=mc^2
Einstein considered the equivalency equation to be of paramount importance because it showed that a massive particle possesses an energy, the “rest energy”, distinct from its classical kinetic and potential energies.
In other words I can derive the same results as relativity and define them in terms of total charge and current. Because relativity was derived from Maxwell’s equations. This is why all measurement of EM radiation (including the sun) are given in the notation of watts.The Neutron possessed a magnetic moment, that gave the scientists a clue (unlike some) that magnetic moments of particles had a primary cause. This is because they are made up of quarks, charged particles that generate magnetic moments because of the complicated interactions of the differing charges as they spin.
Einstein was brilliant. He recognized that particles possessed energy (charge) even at relative rest. That it was not required to move a body in a time varying magnetic field for that body to possess charge. Again, this is what led to the neutron being made up of charged particles, because even at rest, it must possess charge. The movement of this charge in relation to other charges is what causes the magnetic moment in all particles.
Even although it is termed neutral it is not, it is composed of almost equal number of charges that change as they interact with the other quarks within the neutron and the protons in the nucleus and the electron orbiting it and the other atoms nearby. If it was truly neutral, it would posses no magnetic moment. Again why they went looking for the underlying charge of the neutron.
If it is impossible for a neutron to possess a magnetic moment without charge, how is it you believe that magnetic moments can exist anywhere else when it is these same neutrons and protons and electrons thet make up everything that exists??????
So why is the red shift uniform in all directions and increasing from more distant objects?
Are you saying that the Earth is in the centre of the visible universe?
I am not ‘pontificating’ just sayng that calculation shows that gravity ‘constant’ is subject to the relativistic factor, as time is, mass is and speed of light is.
Consequence is that apparent spreading of universe is not greater further away from the Earth in all directions, but the spreading of universe is uniform, and increase in the read shift is consequence of ‘relativistic gravity’
Steven says:
July 15, 2012 at 10:15 am
But we both know relativity was derived from Maxwell’s equations
No, special relativity was derived from [I have here in front of me Einstein’s 1905 paper] two postulates [assumptions]:
1) “that the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of [Newtonian] mechanics hold good”
2) “that light is always propagated in empty space with a definite velocity c which is independent of the state of the motion of the emitting body” [as observed in the Michelson-Morley experiments].
Then in §6 he shows that Maxwell’s equations are consistent with special relativity.
If it is impossible for a neutron to possess a magnetic moment without charge, how is it you believe that magnetic moments can exist anywhere else when it is these same neutrons and protons and electrons the make up everything that exists
Magnetic moments can be generated by electric currents, themselves generated by conductors moving relative to magnetic fields. The magnetic magnetic of the neutron, and the proton, is due to [fractional] electric charges of the gluons composing it. No mystery there. Those magnetic moments are not what we measure under macroscopic conditions.
My previous question:
“the speed at Earth is calculated [from Parker’s theory] to be 320 km/sec.
What speed does EU calculate?”
goes unanswered. To regain some credibility you should answer my questions as I always try to answer yours [the the extent they make any sense].
vukcevic says:
July 15, 2012 at 10:27 am
So why is the red shift uniform in all directions and increasing from more distant objects?
It is uniform because it is observed to be uniform. The red-shift of the Cosmic Microwave Radiation is 1100 and the CMR is VERY uniform all over the sky.
It is increasing with distance because the light from farther galaxies take longer to reach us, during which time the space has expanded more and thus same waves are spread over a larger distance, thus has a longer wavelength. As simple as that.
Are you saying that the Earth is in the centre of the visible universe?
Of course it is. The visible universe stretches in all directions as far as we can see from the Earth. The visible universe for an alien on a galaxy far away is centered on him and not on us.
Dr.S.
Speed of light in the Einstein’s or in any other equations is the universal electromagnetic constant, so regardless of your interpretation, whenever the speed of light appears, there is a direct physical law reference to the electromagnetic processes, there is no other way around it.
EU hypothesis are not of interest to me, and I have no intention in expanding on their validity or otherwise.
Yes and as we know Parker’s theory based on relativity can be written in and expressed in terms of the energy of the system from Maxwell’s equation, so I get the same answer as you, not surprising since relativity is based upon the speed of light and the energy content of all matter (an electromagnetic phenomenon) governed in a vacuum according to the theory of relativity by Maxwell’s equations. Why would you ever think I would get a different answer?