Posted on 05/26/2013 4:08:21 PM PDT by neverdem
Credit: Phys. Rev. Lett. 110, 211302 (2013)
(Phys.org) —A team of Harvard University physicists has proposed the possible existence of a type of dark matter not described by current physics models. In their paper published in the journal Physical Review Letters, the team suggests it's possible that not all dark matter is cold and collision-less.
In the visible universe, galaxies form into a disk shape—the Milky Way is a good example. All of its members align roughly along a single plane, this due to the forces of gravity and spin. Objects form into masses which, over time, spread out into a disk shape. Dark matter, on the other hand, appears to hover around galaxies like a halo, at least according to current models. It's seen as dark, cold and with so little energy that dark matter particles rarely if ever run into one another. The researchers in this new study suggest there may be other types of matter, however, that behaves more like visible matter. And, because of that, they suggest it could bunch up due to dark-matter-type gravity and form disks as well. These disks, which they describe as dark matter component double-disk dark matter, could represent as much as 5 percent of all existing dark matter.
For dark matter to clump, it would need to have other properties similar to visible matter as well. For that reason, the researchers suggest it's possible that there exists dark atoms, dark photons, and likely some form of dark electromagnetic force as well.
Research on dark matter over the years has led to a model that describes dark matter as existing in a ball shape—galaxies sit in the middle of the ball, which would mean observers living in a galaxy would "see" it as existing everywhere around them. But it's possible that other types of shapes exist as well, the researchers suggest, because there are other types of matter in the visible universe. They note that baryonic matter (matter made of strongly acting fermions known as baryons) is believed to make up approximately 5 percent of all matter in the known universe. For that reason, they conclude that it would appear likely that similar differences in dark matter would occur as well, and perhaps in nearly equal proportions.
If true, it would mean there could be whole dark galaxies out there, undetectable, yet as real as those we can see with the naked eye. Much more research will have to be done in this area before adding such types of dark matter to models in general use, of course. Until then, it will remain an abstract theory.
Explore further:
Astrophysicists suggest behavior of Fermi bubbles may be explained by dark matter
More information: Dark-Disk Universe, Phys. Rev. Lett. 110, 211302 (2013) prl.aps.org/abstract/PRL/v110/i21/e211302
Abstract
We point out that current constraints on dark matter imply only that the majority of dark matter is cold and collisionless. A subdominant fraction of dark matter could have much stronger interactions. In particular, it could interact in a manner that dissipates energy, thereby cooling into a rotationally supported disk, much as baryons do. We call this proposed new dark matter component double-disk dark matter (DDDM). We argue that DDDM could constitute a fraction of all matter roughly as large as the fraction in baryons, and that it could be detected through its gravitational effects on the motion of stars in galaxies, for example. Furthermore, if DDDM can annihilate to gamma rays, it would give rise to an indirect detection signal distributed across the sky that differs dramatically from that predicted for ordinary dark matter. DDDM and more general partially interacting dark matter scenarios provide a large unexplored space of testable new physics ideas.
Journal reference: Physical Review Letters 
© 2013 Phys.org
My clueless comment is that I wonder if the effects attribute to “dark matter” are actually due to inter-dimensional interactions of some sort.
Now available at you local Starbucks.
No, it’s not pixie dust. Scientists observe something that they can’t explain, that represents a gap in our knowledge. So they propose a theory of what might be causing it. It isn’t a wild guess, but rather an educated guess based on the knowledge that science has discovered so far. Then they make predictions based on the theory and devise experiments to test their theories. Some theories are supported by the evidence and so become stronger and other theories are proven wrong. The ones that are wrong are scrapped or changed and the ones that most closely fit the data are expanded and refined. In this way our knowledge about the world and the universe is ever expanded. That is how science works and it has given us all of the modern inventions that make our lives so much better. The computer you typed your post on was only a theory once. New medicines are based on theories. We may one day have cheap almost unlimited power based on theories being developed and tested today and we may one day travel to other stars because of theories that are not even imagined yet. I for one am glad their are great minds in the world solving these puzzles and furthering Human knowledge. Because of them we are not all huddling in caves and sacrificing virgins because of a lightning storm, earthquake or volcanic eruption.
Another thing that scientists do is publish their work and show the data they collected so that others can try and duplicate their results or falsify them. They don’t ask to be taken on faith and they don’t hold to their theories in the face of contrary evidence. Not if they care about the truth. They don’t tell they show. They don’t say they prove.
We’re really clueless, but the grant runs out soon so we have to come up with something real soon to get it renewed .... how about super duper heavy weight light dark matter ....
I find your faith in scientists truly moving. In the light of such devotion, could you explain to me their unswerving support of the proven hoax of global warming?
As a long as orthodox cosmologists keep their blinders on and REFUSE to look at a force that is as infinite in its reach as Gravity, one that we can see evidence of everywhere we look in the universe, but one which is thirty-nine orders of magnitude (1,000,000,000,000,000,000,000,000,000,000,000,000,000 times greater than gravity and just as infinite in reach) STRONGER, they will keep invoking magic and other excuses to make their beautiful, multidimensional house of cards stand.
Once they accept the fact that electromagnetism and its effects on plasma (the state of 99.99999999% of all matter in the universe) and the flows of energy throughout this Electric Universe, will they begin to understand how the universe works and realize that what they cannot explain using their Gravity driven model is easily explained without magical, non-existent dark matter, and in fact is predictable and demonstrable in the laboratory, using the Electric Universe models and theories. In fact, what orthodox cosmologists are continually surprised and shocked to find in the universe, have been predicted and expected findings of the Electric Universe cosmologists. . . repeatedly.
These orthodox cosmologists have been looking hither and yon for the chimera of dark matter and dark energy to make their theories match the observations and have NOT ONCE FOUND ANY. . . EVER. Yet every new observation confirms the predictions of the theories of the Electric Universe cosmologists, consistently.
The test of any scientific theory is how well it can predict future finding and observations. The predictions of the orthodox cosmologists have consistently failed this test for the last sixty years. The predictions of the Electric Universe cosmologists have had about a 95% accuracy over the last 85 years. Yet the vast majority of funding goes to the failures. Go figure.
I don’t have faith in science. I have trust in the scientific method and those who practice it based on reason and its track record. Not all scientists have unswerving support for the theory of anthropogenic global warming. Many scientists point out the flaws in the theory. After all it was a scientist who busted Michael Mann when he was hiding data in order to show the results he wanted. Those who do have unswerving support for a theory that has not been proven are not scientists but propagandists. Unswerving belief in something that is not proven is faith, not science.
“super duper heavy weight light dark matter”
—tastes like chicken (sorry, couldn’t resist),
“They don’t tell they show. They don’t say they prove.”
And I give you,,string hypothesis. (Can we please not call it a theory until at least -one- experiment can be done to support the hypothesis?)
Something like the "ether" that used to be posited as the medium that allowed electromagnetic waves propagate through vacuum.
I really like your comments in this thread but likely even you have to admit that work in the areas of theoretical physics and cosmology is a long way from application of the scientific method, by definition as well as by practical limitation. Maybe some day the subject area of cosmology will become the realm of the scientific method. Right now about all you have are observational experiments like LIGO (Hanford LIGO near me), which so far have failed to confirm theories.
Blasphemy!!! You have bumped heads with Anthony Watts on this topic, no?
I’ve said this for years.
I once found a clump of dark matter, but I stirred the milk and it turned into a tasty chocolate treat. Nestles Quik explains the universe.
Re: your description of how science works.
Yes, that’s the way it is supposed to work. . . Except it doesn’t. You have logical fallacies rearing their heads all over the place in scientific research. One of the biggest is the Appeal to Authority Fallacy where a fact is not challenged because so-and-so renowned Scientist said it is so. If it’s written in the text books as fact, a law of science, etc., it is not likely to be challenged. . . even if it is flat out wrong. These established shibboleths can hold back scientific progress for decades.
For example, in this case there is a major one. Orthodox cosmologists hold it as a matter of faith that “there are no electric charges in space.” They are taught this in their Astronomy classes as a fact. They are taught another one as well: “Gravity is the force that drives the universe” and using that shibboleth they try to squish and squeeze every phenomena they see in the universe through the causality lens of Gravity, a monopolar force that results in some very strange pronouncements and contortions to make the observations fit. Dark matter and dark energy are examples of these contortions.
Once the existence of plasma physics and the flows of charges through space is accepted, the things we see through our telescopes, both optical and radio, are totally explicable. In fact we can create them in the plama physics laboratory and they are SCALABLE from the microscopic to the cosmic, and predictable, using plasma mathematics. EVERYTHING. No need for superstring theory, black holes, neutron stars, Quasars, dark matter, dark energy, and other unseen constructs of orthodox cosmology to explain the universe as a gravity run machine. All of the above become explainable under easily understood electric and electronic models in the flows of energy through highly charged plasma through space. . . something we can see everywhere we look. . . if they will only open their eyes, and stop listening to what they were told by those old dead scientists. . . who made a wrong assumption!
Ask an orthodox cosmologist to explain a Herbig Haro object. They will tell you about models of jets whirling like “lawn sprinklers” shooting hot gasses into space from a rapidly spinning star. They will never acknowledge that “hot gasses” really means “plasmas” which are matter stripped of their electrons, I.e., matter in a HIGHLY CHARGED state. They have no clue what keeps these Herbig Haro objects cohesive in spiraling forms over dozens of light years (hint: it’s NOT gravity!). They know about the solar wind flowing from our sun, but they really have no clue of the source of the CHARGES it carries. Ask them about the composition of a comet. . . and why the Electric Universe cosmologists CORRECTLY predicted they were not “dirty snowballs” and would be found to be indistinguishable from every other asteroid (true). . . except in the HIGH ELECTRIC CHARGE THEY CARRY!
These predictions went against the shibboleth “facts” that your mainstream scientific method had produced and taught everyone so that no one would PERMIT any research that looked at anything different! This worship of orthodoxy is found in EVERY FIELD of science today, much to the peril of our future advances.
Don’t even get me started on scientific fraud and politics that distort the beauty of true science that gives us the crap like what’s happened to climatology.
Yeah, we don’t need to no nuthing. Wast all are time with this sienntific stuff.
Don't feel bad. They don't have the smarts to understand what the heck they're talking about either.
Yeah I get your point. I guess I was just responding to what I perceived as the mocking tone in the post about pixie dust. My point is that putting forth hypotheses and theories is how we as conceptual beings explore the world around us. I don’t think anyone out there is saying that string theory is in any way accepted as true. The article title says scientists “suggest”. They aren’t saying it is proven or assuming it. I enjoy reading the science articles posted on Freerepublic but some of the anti-science mentality on here makes my head explode. I shouldn’t even respond. I just hate to see these men and women impugned when they are just searching for the truth and our lives are better for their discoveries. We always get the obligatory “they must need a new grant” posts and the “scientists don’t know anything” posts. Then there is the science is a religion posts. I guess I should just stop coming here. All it does is put me in a bad mood.
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