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…
Considering that human knowledge of gravitation can not accurately account for more than two objects without heuristically fudging the equations (three body problem), I find it the height of hubris when highly educated folk (who know their gravitational theories can not account for “varying differentials of the Moon’s orbit”) think that because the galaxies move in ways their models don’t explain very well, that it must be attributable to dark matter and energy that make up to 96% of the universe. Talk about a colossal fudge factor. How about a little occams’ razor and honesty?
1. We (humanity) really do not know how gravity works. We have models and theories galore that attempt to model the effects of gravity, but the mechanism by which it functions is unknown.
2. Despite this slight inability to deal with three objects interacting gravitationally with precise accuracy (a galaxy constains slightly more than three objects), a large portion of the mathematics, physics, and cosmology communities are ready to declare that their gravity models are fine, good enough to declare that 90% (or more) of the galaxy is composed of undetectable stuff…dark matter, energy, super condensed fudge, whatever, which has to be there so their models will be able to agree with observation. Models are supposed to resemble reality, not the other way around.
When you can’t account for 90% of anything in order for you theory to be accurate, your theory isn’t working very well.
Christian Takacs says:
July 12, 2012 at 2:30 am
Considering that human knowledge of gravitation can not accurately account for more than two objects without heuristically fudging the equations (three body problem),
Another example of the low level of knowledge most commenters here have. That there is no closed simple equation for more than two bodies, does not mean that we cannot accurately account for such objects. The equations can easily be solved numerically:
http://ssd.jpl.nasa.gov/?horizons
“The JPL HORIZONS on-line solar system data and ephemeris computation service provides access to key solar system data and flexible production of highly accurate ephemerides for solar system objects ( 587479 asteroids, 3153 comets, 176 planetary satellites, 8 planets, the Sun, L1, L2, select spacecraft, and system barycenters”
Dr Anthony Fallone says:
July 12, 2012 at 2:06 am
I’m shocked at how dumb most of the comments here have been, or have displayed fruitcake thinking. I always read WUWT and have agreed with most of the comments on so-called Climate Change’, regarding myself as a sceptic. Now, though, I shall be careful about accepting what is posted here on climate if the postings on dark matter are the true standard of intelligence of posters.
With this I wholeheartedly agree. Let the people referred to come back and further demonstrate the truth of the above sentiment.
Peter Melia says:
July 11, 2012 at 12:18 pm
We are told, and easily accept this, that if our object was ejected violently in a perfect vacuum, and free of gravity it would never slow down, it would just continue on at the same speed, forever.
How is it then that the particles ejected during the big bang, do not slow down, do not continue at the same speed forever, but actually accelerate. What is the accelerating force?
Perhaps a clue here…
Photonic Laser Thruster Makes Its Debut
http://www.photonics.com/Article.aspx?AID=28582
All we need to do is give real mass, size and spin to the photon for it to provide the necessary force to accelerate the galaxies away from the centre of the cosmos. Maybe light is the new dark?
Tenuk says:
July 12, 2012 at 4:39 am
Peter Melia says:
July 11, 2012 at 12:18 pm
We are told, and easily accept this, that if our object was ejected violently in a perfect vacuum, and free of gravity it would never slow down, it would just continue on at the same speed, forever.
The difficulty here is that the ‘objects’ of the Big Bang were NOT ejected violently. They actually don’t move [except for small local velocities caused by mutual interactions] at all. The expansion of space takes place with or without any objects in it.
Leif,
“The expansion of space takes place with or without any objects in it.”
Here and in my ignorance I thought the CONSENSUS view was that expansion occurred BETWEEN objects such as Galaxies!!! Maybe I should view your Cosmology presentation and see what a heretic you really are!!!
Yes I realize the guy in the wheelchair thinks the expansion is homogeneous which means he also is somewhat heretical!!
iamreplete says:
July 11, 2012 at 11:39 pm
Out there, in the hinterlands of science, among all of those millions on uncounted scientists, surely there must be one, just one, who can answer my simple questions!
All your questions are answered in the wiki article of the big bang. If you cannot understand it, maybe something simpler, as an introductory physics course might be recommended.
Usually simple questions have complicated answers, not suitable for a blog discussion.
Alexander Feht says:
July 12, 2012 at 1:39 am
Alas, he is dead — he died a pauper, betrayed by America and the whole world, the same world that owes him its very survival.
Not whole world, the small nation of his origins does as much as it can to keep his name and memory alive. His work is studied in detail at Electro-technical faculty in Belgrade, the labs where practical experiments are carried are overlooked by his statue, there is museum dedicated to Tesla and his inventions, Belgrade Airport is named after him, so visitors all over the world are reminded of Nikola Tesla’s name.
There is some more info on my website:
http://www.vukcevic.talktalk.net/Nikola%20Tesla.htm
Here you can hear N.Y mayor LaGuardia’s eulogy at Tesla’s funeral
http://www.teslasociety.ch/info/ton/Fiorello_La_Guardia_uber_Tesla.wma
And much more on website:
http://www.teslasociety.com/index.html
anna v says:
July 11, 2012 at 11:50 pm
====================================================
Dear anna,thank you for your partial response, And yes, I appreciate that science has advanced a great deal. One such example is Leif Svalgaard says:July 12, 2012 at 3:55 am.
And yet, at larger scales we simply can not use the same maths, based on the SAME OBSERVABLES. Hence some UNOBSERVED SOMETHING, exerting some force over 90 percent greater then all OBSERVABLES, is operating on these vast scales, but is apparently absent on smaller solar system scales as in the post by Leif which I referenced, where that 90% of something is not necessary to explain the OBSERVABLES Leif describes. So how does the same force, gravity, operating on solar system size scales where dark matter must be absent, (ie, not needed to explain the very complex relationships Leif’s link expounds on) suddenly operate differently, just because the scale has changed? Is dark matter absent within solar systems, but only present between galaxies? Or is there a different force operating on vast galatic scales, which does not operate on smaller scales, just as the atomic force operates on a molecular scale, but is not involved in the solar mechanics Leif discusses?
Let me try my sand castle assertion/question this way. An egg is sitting on a counter with a slight inclination. The egg is on the uphill side of an empty tissue box. Anna opens a window, a gust of wind moves the empty tissue box, the egg rolls down the incline, falls 32″, and shatters on a ceramic floor. Now a detailed mathmatical explanation of all the physics involved can explain all that is observed.
We can also run a film of the event backwards, The same maths reversed, can elso mathmaticaly explain every event, but, even though the math is 100 percent correct, it is still 100 percent wrong.
Just because the math is correct, does not mean nature obeys it.
My simple point is that when trying to quantify something where we can only see the effect,(say the answer is 10) but not the object causing said effect, we do not know if 10 was reached by a series of math and numbers from a known force, gravity, or a different force reaching “10” differently. BTW, yes gravity is a known, but not an easily explained force.
Anna, you also said…
“And as for Steven’s comment, in a sense it is true.
We each of us sit in our head and observe the world around us. We know it by proxy par excellence. Have you considered that everything you experience might be a construct of your imagination? 🙂 a grand dream, including this comment?”
—————————————————————————————————
Smiles, yes, but still in science we detect cause and affect via instuments which observe. thus my eyes see the “water” which destroys the sand castle, thus the water is detected. We have yet to detect either gravity (we only see its effect) or “dark matter”, we only see its effect. I maintain our instruments are too crude.
Now when I ask very simple questions, based on cause and effect, the structure of all science, I can only hope for an elevator speech answer. What is this space that can expand, and what does it expand into? I really hope for an answer. I see space as a three D constuct of height, width, and depth, each of which are infinite, and when anything else quantifiable is added, time becomes another demension operating within cause and effect principles.
BTW people, ( I do not mean you Anna) stop getting all emotional. It may well be that your answers are simply beyond the comprehension of lay members.
”
Leif Svalgaard says:
July 12, 2012 at 4:56 am
Tenuk says:
July 12, 2012 at 4:39 am
Peter Melia says:
July 11, 2012 at 12:18 pm
We are told, and easily accept this, that if our object was ejected violently in a perfect vacuum, and free of gravity it would never slow down, it would just continue on at the same speed, forever.
The difficulty here is that the ‘objects’ of the Big Bang were NOT ejected violently. They actually don’t move [except for small local velocities caused by mutual interactions] at all. The expansion of space takes place with or without any objects in it.
”
Prior to the apparent discovery of an accelerating universe a couple of decades ago, the cosmological question was whether or not there was sufficient mass in the universe to cause a big crunch due to gravitational attraction where everything collapsed back again or whether the universe would simply continue expanding. In either case, it was expected that the expansion we observe would slow down some. Instead, the ‘discovery’ indicated that the universe’s expansion is speeding up.
However, although it has been almost universally accepted, (parallel to AGW concensus guff), there remains a serious possible problem. The detection of this acceleration was by the type Ia supernovae observations which was assumed to be caused by a white dwarf sucking up matter from a companion star until it reached 1.4 solar masses – the limit in size for a white dwarf – beyond which it would collapse, creating an explosion (supernova) of a standard size. This is a questionable assumption and some recent (fall 2010 or 2011) paper(s) have failed to detect sufficient x-ray sources for candidate white dwarfs acreting matter to explain the number of type Ia supernovae. This leads to the prospect of type Ia supernovae primarily being from collisions and that seriously affects the accuracy of the standard explosion size which potentially throws the whole faster expansion idea into doubt.
Human nature being what it is, if faced with ‘dark matter’ , it’s ‘sexier’ to hypothesize about exotic dark matter like particles never before detected or microscopic black holes than it is to hypothesize about a bunch of brown dwarfs, planetoids, asteriods, comets, or interstellar dust bunnies.
Skepticism is important with all science, not just global warming. Elegance is a concept that many physicists think must be part of any accepted theory. The amount of chewing gum, duct tape, bailing wire, and superglue holding modern cosmology together is the antithesis of elegance. If this Higg’s boson discovery is real and if the Higg’s particle actually is responsible for gravity, that could potentially spell the end for the general relativity concept of warping of space and I don’t know what sort of ramifications might come from that.
Peter, you might like to find and read some of the books written by Fulvio Melia. He’s an interesting character (university of arizona astronomer/astrophysicist).
While reading (far too) much of the above the following came to mind. The only things you HAVE to know are how to make enough of a living to stay alive and how to get your taxes done. All the fun parts are optional.
Leif I admire your patience.
David says:
July 12, 2012 at 5:29 am
So how does the same force, gravity, operating on solar system size scales where dark matter must be absent, (ie, not needed to explain the very complex relationships Leif’s link expounds on) suddenly operate differently, just because the scale has changed? Is dark matter absent within solar systems, but only present between galaxies?
There is no indication that gravity works any different on different scales. And about dark matter present in the solar system: We do expect there to be some, possibly in the sun. Certainly there is dark matter within the galaxies [and not just between them; that is what makes the rotation curve flat. The thing is that the density of dark matter is extremely low, so difficult to observe on the small scale.
I have to say, I am a bit bemused by the onslaught of comments attacking this article. Some folks seem not to appreciate that dark matter is just code for “there is something acting gravitationally in the universe, where no matter can be detected and we don’t know what it is.”
Now what is so hard to accept with that statement?
It really is about distances. Distances translate into time. Each time we peer further into the cosmos we are looking back in time. Each time up our kit we see an older universe.
I can see how earlier parallax type measurements could be replicated but the Caephid variables cannot, however we cross reference with red shift measurements and all is consistent a long way away. Well it would be wouldn’t it.
I am not saying these guys are wrong with their strings and ropes but I cannot take their 3D model on board without some degree of error bar around the distances. A lot of guys on here are skeptical about things they understand, and lots about things they don’t understand. I am curious about lots of things now and my experience with the scientists in AGW has taught me how important it is to question everything.
Vince,
“there is something acting gravitationally in the universe, where no matter can be detected and we don’t know what it is.” Now what is so hard to accept with that statement”
Why yes, there is a HUGE problem with that statement. Your ASSUMPTION that only gravitation could possibly be causing the effect in question.
Leif, If DM tracks the density of “normal” matter ( and some think that normal matter clumps around DM ) then if the universe consists of about 4% normal matter and 25% DM (and 70% dark energy) then wouldn’t one expect that the typical DM density to be about 5 times that of normal matter on average?
Perhaps microlensing will lead to a better understanding of things as we manage to get past the atmospheric lensing difficulties (turbulence). I think we’ve yet to spot our first Oort cloud object in place.
“I would also love to think that the expansion of space is the reason for my expanding waistline. Unfortunately, gravity is strong enough to prevent expansion of anything smaller that a cluster of galaxies.”…We have loosened Orion’s belt
It is unfortunate that the exhilaration and personal accomplishment in these observations and experiments is lost to most commentators. I give Lief, Mosher and Anna much leeway in the tone of their responses. It is easy to say, they observed nothing or the theories are kludged. The complexity of things that are beyond our common senses cannot be dismissed so cavalierly. The work behind the theories is ongoing and should be a source of fascination for everyone interested in how things work.
anna v. et al
I put “scientifically” in quotes to indicate sarcasm. In future, perhaps I should use [sarcasm on]/[sarcasm off]. There is no discipline of science that does not have the same problem as does the particular subset of climate research called “anthropogenic global warming”. There is an existing dogma in every field of research. Science careers are built on pet theories and then codified as [sarcasm on] “facts” [sarcasm off]. And then taught in the universities as “facts”, and then in the grade schools as “facts”. Thus the kids are indoctrinated in the currently prevailing theories and any thinking “outside the box” is not just discouraged, but actively ridiculed and mocked. This is ably demonstrated by AGW, and I find it amusing to see it everywhere I look. I only know a few scientists who truly will consider options “outside the box”.
ian
Re Vince Causey: indeed, I’ve often written about a “gravitational scalar” enabling ambient mixing of stars in elliptical galaxies and globular clusters. So now Leif states “the density of dark matter is extremely low, so difficult to observe on the small scale”. Sounds like much the same thing, actually.
“Vince Causey says:
July 12, 2012 at 7:37 am
I have to say, I am a bit bemused by the onslaught of comments attacking this article. Some folks seem not to appreciate that dark matter is just code for “there is something acting gravitationally in the universe, where no matter can be detected and we don’t know what it is.”
Now what is so hard to accept with that statement?
”
Vince, nobody ever got a research grant – government or otherwise – who concludes that “there is something out there where nothing has been detected and we don’t know what it is” Besides, dark matter, or DM, is a lot shorter than using a whole phrase or some sort of acronym like “tisotwnhbdawdkwii”.
There are other biases that enter into things as well. How many prefer the notion that space itself is expanding rather than the notion that the speed of light in a vacuum, c, is slowing down over time? Hint, most prefer their universal constants to be constant, even though classical electromagnetic theory indicates that the speed of light is related to the permeability and permittivity of the medium in which it is travelling, be it water, air, or empty space.
Leif Svalgaard says:
July 12, 2012 at 7:27 am
And about dark matter present in the solar system: We do expect there to be some, possibly in the sun.
Why did you have to say that?
My coffee went all over my keyboard, had to turn of pc and do cleaning and drying.
Never, ever expected to hear anything do funny on a thread of gravity !
Dr Anthony Fallone says:
I’m shocked at how dumb most of the comments here have been, or have displayed fruitcake thinking. I always read WUWT and have agreed with most of the comments on so-called Climate Change’, regarding myself as a sceptic. Now, though, I shall be careful about accepting what is posted here on climate if the postings on dark matter are the true standard of intelligence of posters.
I agree 100% This whole exchange has left me more than a little concerned about the quality of information that I’ve been getting here.
James,
” I agree 100% This whole exchange has left me more than a little concerned about the quality of information that I’ve been getting here.”
Absolutely!!! I recommend that all of you consensus types run away very fast and hide amongst those who are only interested in reinforcing each others ideas so there is no doubt in your world to upset you!!
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA
****
cba says:
July 12, 2012 at 6:38 am
Human nature being what it is, if faced with ‘dark matter’ , it’s ‘sexier’ to hypothesize about exotic dark matter like particles never before detected or microscopic black holes than it is to hypothesize about a bunch of brown dwarfs, planetoids, asteriods, comets, or interstellar dust bunnies.
****
I’d think those were very first things astronomers looked at to try to explain things, and those candidates were found lacking/implausible.
****
James Hastings-Trew says:
July 12, 2012 at 8:30 am
I agree 100% This whole exchange has left me more than a little concerned about the quality of information that I’ve been getting here.
****
You’ve got to use your own mental “spam filter”. Some posters here have discredited themselves to the point where I automatically skip over their comments. Unfortunate, but WUWT is dedicated to being an open website, as long as the site policies aren’t violated.
Vince, it is easy to accept that the inferred motions of galaxies don’t agree with the predictions of the standard model. It’s much harder to accept that the problem is solved by calculating where some matter “should” be, drawing a target around the empty space, and claiming the target is filled with otherwise undetectable and unpredicted clumps of particles that don’t fit anywhere else in the theory.
Leif,
“And that is spectacularly confirmed by the fact that we indeed cannot see it.”
The fact that it is invisible is spectacularly confirmed by the fact that you can’t see it? That’s an unusual logical construct.
“We can, however, measure the gravitational effects from Dark Matter which shows it is there, just like in the 19th century we hadn’t seen the planet Neptune, but we knew it was there because of its gravitational effects on Uranus. We could even from those effects calculate where Neptune should be, and that is indeed where we found it. Such is the power of science.”
Or, you could be wrong. Place your bets…
So, can we at least get agreement that nothing has actually been “detected” but it has rather been “inferred” from general relativity and how we “believe”, based upon theory, that gravity, light defraction, space expansion and a variety of other factors are working? If we knew all there is to know about all of these issues it would be different, but since we do not, any amount of healthy skepticism should leave some doubt of what is causing the effect being observed. Otherwise we are treating our theories as dogma just like the AGW crowd.
Name calling or snide remarks regarding those who may have read and agree with other potential explanations which obviate the need for dark matter or dark energy is not productive. After all, it is mathmatical models which tell us that there cannot possibly be that much additional baryonic matter out there to answer the riddle of where all the apparent additional mass comes from to create all of the apparent additional gravity. I do not believe anyone has actually hands on inventoried the mass of the universe.
Leif,
Remember that cosmology is a rather esoteric and mathematical field. It is hardly surprising that anonymous laymen display their ignorance. That said, the arrogance of some of these uninformed posters is a bit annoying.
You usually don’t become noticeably agitated and just do your best to give a factual response and refer the uninformed poster to a resource to better educate themselves. (Occasionally tossing in an amusingly sarcastic remark that, while at the expense of the poster, is usually not too severe.)
It seems that lately your patience and good nature have been tested. Remember that for every arrogant know nothing there are many other readers that are trying to educate themselves and are eager to accept a scientific theory that is backed up with testable evidence.
Try to cut the ignorant some slack and don’t condemn all of us that frequent WUWT.
Ahh yes Lancifer, sheer breathtaking ARROGANCE!!!
On the one foot, you tell me I am arrogant and ignorant (absolutely I am ignorant!!!) for questioning the greats like Einstein and others for their work decades and more after it was done. Yet, when I tell yoou that Einstein himslef decided that he made a mistake with the Cosmological Constant you shush me and tell me YOU know better than Einstein!!
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA
I’m still trying to figure out just what is actually new about the announcement. Below are some links to other earlier efforts of mapping DM. Evidently, it’s the assumption that the DM observed between the clusters in the filament is not or was not a part of the clusters. Mapping DM distributions using gravitational lensing is not something that is brand new as the first measurements were done around half a dozen years ago.
http://hubblesite.org/gallery/album/exotic/pr2010026a/
http://www.nasa.gov/mission_pages/hubble/science/dark-matter-map.html
http://www.nasa.gov/home/hqnews/2006/aug/HQ_06297_CHANDRA_Dark_Matter.html