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
Like Potus
The laws of gravity don’t behave like we expect, therefore it must be magic pixie dust, or ether, or global warming or something.
>>Like Potus<<
GMTA but I didn’t have the guts to post it LOL!
Exactly, these morons have absolutely no clue
>> possible that not all dark matter is cold and collision-less.<<
Like my ex-wife...
>>dark matter as existing in a ball shape<<
Also like my ex-wife...
im not smart enough not to
I have a crazy idea. Why don’t they show me a single particle of regular “dark matter” before they tell me there are others?
Note the emergence of light matter through the portal...
“The laws of gravity don’t behave like we expect, therefore it must be magic pixie dust,,,”
It never even crosses their mind that they could be wrong. I feel like in a few hundred years, physicists will shake their heads -in amazement- at the theories that gained mainstream acceptance in this era.
obama is dark matter in a quantum state when you aren’t looking at him he isnt there and even when you are you arent sure
lol,,great!
The only reason I click on these threads is that I’m fascinated with the unknown. Unfortunately I don’t have the smarts to understand a darn thing they are saying.......but I’m still fascinated!
I produce some dark matter every morning.
You got-
Dark Matter
Darker Matter
Very Dark Matter
Really Dark Matter; and
Really, REALLY Dark Matter
....
Quite. I too am astonished at the contortions gone through to explain away the fact that their theories don’t explain the observed facts, rather than considering the possibility that their theories are themselves wrong, and trying to develop new theories that DO explain the observed facts.
OTOH, maybe dark matter does exist. I just object to the assumption that it MUST exist.
I also wonder if some of these anomalies might be explained by the existence of the other 8 or whatever dimensions required by the various string theories, etc.
I refer to it as my “morning Obama.”
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