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.
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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…
Hurrah! A vignette on astrophysics, gravitational lensing, and physical confirmation of dark matter!!!
I will look forward to them laying out how they are certain about the distances from us these phenomena are.
Who was the last guy to talk of drivel?
I read this a few days ago. I am sure they mapped something. I am sure something has caused the measurements they and others have made. Everything else is speculation. It is fun to speculate and play the what if I… game. At least the cosmologists are rational and sober (well maybe not) enough to take themselves no more seriously then the empirical measurements will.
So, they have a map of where their fudge factor needs to be located to to explain, within standard accepted physics theology, their lack of understanding of the interaction between matter, energy and the resultant curvature of space (gravity). Sorry, I ain’t buying it…96% of the visible universe is “dark BS”. Think outside the box, guys, you’re missing something!!
This question will, to the vast majority of your readers, be certain evidence of the questioners (my) lack of education, knowledge and etc. However, if some kind person could bear with me and answer my question, I would be grateful.
Question.
The current theory of the origin of the universe seems to state that after the big bang, matter streamed outwards from it’s origin and has continued accelerating ever since. Dark matter slows this acceleration down.
But our common experience is that any object we know of which is ejected violently from something else, by whatever means, will eventually lose speed and stop.
OK, this is because of environmental conditions around the ejected object.
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?
I agree. with Jim G.
it seems to me is a 96% of the universe is made up of mathematical particles and hyperdense equations.
These co(s)mic models remind me so much of global warming models.
And, by the way, they did not “directly detect it” or “see it”, they inferred it based upon their theoretical “beliefs”. Check that subaru telescope for rust, my first one, car that is, rusted out quite rapidly.
Did you see this
http://www.dailymail.co.uk/sciencetech/article-2171973/Tree-ring-study-proves-climate-WARMER-Roman-Medieval-times-modern-industrial-age.html ?
Sorry, if you already knew it.
[REPLY: Yes, we did. -REP]
Concerning the Dark Matter model I strongly recomend to read the new paper of P. Kroupa titled “The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology”, published in the Publications of the Astronomical Society of Australia.
Link: http://www.publish.csiro.au/paper/AS12005.htm
Direct link to the pdf: http://www.publish.csiro.au/?act=view_file&file_id=AS12005.pdf
Jim G.’s wake-up call should be taken seriously. Astronomer’s interpretations of gravitational lensing incorporate unquestioned assumptions. This is not really a direct detection; it may be just another example of confirmation bias. This report and even one hundred more “verifications” of cold dark matter may not stand up against an overwhelming falsification, which may come at any time in the future.
It sounds more like they’re describing electrical currents in plasma than magically invisible dark matter.
I wondered when someone was going to announce discovery of the imagined dark matter. I suspect there is a tautology at work here. Dark matter was postulated because gravity (as we know it) seemed too weak to account for the behaviour of spiral arms, etc. Shouldn’t we be re-evaluating what we “know” about gravity? I think the path to a unified theory is blocked by such fantasies as dark matter, but like Ptolemy with planetary motions in a geocentric universe, we will shoe-horn things to fit and even be able to make predictions with this painful cobbling.
Keith Battye says:
July 11, 2012 at 12:07 pm
I will look forward to them laying out how they are certain about the distances from us these phenomena are.
There are lots of places you can an explanation of that. Look around, and don’t pretend to be dumb. But the observation reported here does not depend on the distances being accurately known.
I may have misunderstood the principles but I thought they were describing a 3 dimensional model, in which case the distances are surely important.
Take a picture of two humans. One is sleeping, and the other is walking. The sleeping person is consistent with physical models, but the walking person exhibits unexplained motion of its appendages. I propose that the arms and legs are tugged by clumps of disembodied gravity surrounding the person.
Too right Jim G!
Trained in cosmology myself, the accepted cosmologyical model was all nonsense, nothing like science or physics. Just a load of very speculative maths theories, where if they broke, another fudge factor was chucked in, it was a routine. Then cosmologists would pat them selves on the back for another fudge factor ‘discovered’.
Today I’m really please to say I’m seeing the sad religion of dark matter and friends is losing substancial ground to other theories. The lectures on other theories are packing out theatres and are financially solvent enough to grow their own community.
It been great fun to follow it. The internet is an important media for these alternate ideas to prosper.
It turns out the establishment model has no right calling their model ‘ the standard model ‘ . It leaves out parts of the physics they don’t like.
Jim G says:
July 11, 2012 at 12:07 pm
Think outside the box, guys, you’re missing something!!
Dark Matter is thinking out of the box you seem to be in.
Hold on, get ready for the kooks w/their pet theories….
Sheer nonsense. A term in an equation is not “matter”.
If they would give up on particles altogether and go back to de Broglie’s idea that everything is just waveforms, they might start making sense. Simplify, simplify, simplify.
Will the Higgs boson make up dark matter? gravity and all. Maybe dark matter is only Higgs bosons.
We find the God particle and dark matter in the same week. Who’d a thunk it.
I further propose that, by taking pictures of millions of walking humans and using motion blur or the Doppler effect to produce a map of the dark matter causing their anomalous movements, perhaps we can gain a better understanding of how these walking humans formed and predict where they will be located in the future.
Good old Dark Matter. If observations don’t match the theory, throw away the observations.
The theory predicts that we should be able to see lots more stuff in our telescopes than we can. Therefore most of the stuff must be invisible. Jeenyus.
Keith Battye: a good introduction to this topic, and how they know with a fair degree of certainty how far away distant objects are, can be found in the book “A Universe from Nothing” by Lawrence Krauss. It’s available on the iBooks store, among other places.
Specifically – there is a direct relationship between the brightness of a certain kind of star called a Cephid, and the period of it’s oscillations. There’s a direct relationship between the brightness of a star and its distance from us (via the inverse square rule). Therefore, if you know the period of a Cephid star, and its brightness, you can work out with a fair amount of accuracy its distance from us. The distances were then later confirmed by using a different mechanism involving the relationship between the brightness and duration of supernova stars (about 3 supernova are observable somewhere in the sky on any given night). These tools give us an extremely accurate picture of the scale and distance of the Universe.
Furthermore, an examination of the spectra of these stars can show red or blue shifts, which can tell us with a high degree of accuracy at what speed distant objects are moving away or towards us. So we know that the Universe is expanding, how fast it has been expanding, and even that it is accelerating, not slowing down due to gravity.
The book is also a great introduction into why theories such as “dark matter” and “dark energy” are important because there simply isn’t enough visible matter and energy in the universe to explain its “flatness” and the acceleration of expansion that we are witnessing.
Thank you for that information, it is greatly appreciated.
Having followed most of it I would still express some concern about the distances being stated as the assumptions seem to accumulate.
My gray matter rejects dark matter. Observation of light bending in the 1919 total eclipse was the first proof of Einsteins Relativity. For Universal models, i prefer the “Einsten-Godel Rotating Universe Model”…surpressed since 1949. The Cosmologists are not robbing us of big ‘alarm’ grants, but openess is lacking. See “Federally Funded Franken Science” on the possible reasons why…..part of a series including “The Cure for Cosmology’s Peptic Ulcer” and “Mysterious ‘Dr X’ says Universe is NOT Expanding”. [the post AGW science debate?]
A good tutorial on cosmology can be found here http://www.leif.org/EOS/Comology/cos01.pdf
There are 17 chapters. To see chapter nn use cosnn.pdf in the above link.
Many of your questions may answered there. Before shooting your mouth off, go check out the link(s), then pose questions to things you don’t understand.
I’m not a big believer in dark matter. When you have to event something out of thin air to explain an expanding universe you are really starting on the wrong end of discovery. And when you make a theory that states I will look into the universe until I find data that proves my theory you create an eventuality. The universe is big. Its really big. You look long enough your going to find absolutely anything you want. It becomes probable that you will find you own name written in gold with in a some yet unknown nebula. This isn’t science, its a money grab.