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Author Topic: Does dark matter have structure?  (Read 3547 times)

Leo Vela

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Does dark matter have structure?
« on: 17/06/2010 21:30:03 »
Leo Vela  asked the Naked Scientists:
   
Is dark matter simply a framework around which matter affixes itself to or does dark matter have its own independent structures, meaning is there a dark universe with dark galaxies, and dark planets, and maybe even dark lifeforms?

Thank You,

Leo Vela
Miami Beach, Florida

What do you think?
« Last Edit: 17/06/2010 21:30:03 by _system »


 

Offline tommya300

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Does dark matter have structure?
« Reply #1 on: 17/06/2010 22:26:31 »
I am not sure of the others but you can find dark lifeforms in the the souls of man right here on earth.
Just recently stumbled over this link.
There is some info on the research relating to an error in calculating the big bang theory

http://www.dailymail.co.uk/sciencetech/article-1286668/Dark-energy-matter-exist-claim-scientists.html?ito=feeds-newsxml

It is to bad because it really captured my imagination. I was thinking that dark matter was full of least energetic photons just waiting there to exchange energies. That is me dreaming.
« Last Edit: 17/06/2010 22:30:31 by tommya300 »
 

Offline Soul Surfer

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Does dark matter have structure?
« Reply #2 on: 18/06/2010 09:22:57 »
Dark matter does have a weak structure on the scale of galaxies and galaxy clusters and it has a very slight change of density associated with gravitating masses like stars and planets but it cannot have much fine structure because it interacts only by gravity (or it would have easily been detected) and the particles cannot loose energy by collisions (other than by creating very weak gravitational waves) and particles do not stick together like atoms do.
 

Offline graham.d

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Does dark matter have structure?
« Reply #3 on: 18/06/2010 09:39:12 »
I agree with SS. The models of the distribution of dark matter necessary to give the apparent distribution of mass and velocities of normal matter in galaxies (and galaxy clusters) suggest it only interacts with matter very weakly. The distribution seems to be (very roughly) spherical even with galaxies which have settled into discs, and extends well beyond the galaxy's edge. This would suggest it only interacts with itself very weakly too. It is therefore unlikely that there would be much detail in any "structure" to dark matter. The forming of anything complex with dark matter would be an idea that may even stretch the writers of Star Trek.
 

Offline acsinuk

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Does dark matter have structure?
« Reply #4 on: 18/06/2010 10:17:48 »
Hi SS and all
Would you consider the Oort cloud as dark matter?

CliveS
 

Offline graham.d

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Does dark matter have structure?
« Reply #5 on: 18/06/2010 10:47:51 »
No, at least not with what is usually defined as "dark matter". The Oort cloud is thought to be conventional matter and the source of comets - definitely normal matter (ice, methane, etc.).
 

Offline LeeE

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Does dark matter have structure?
« Reply #6 on: 20/06/2010 13:06:46 »
I've just posted this in the other current thread on DM/DE but it applies here too:

Quote
Rather than being answers for anything, both dark matter and dark energy are really just descriptions of a perceived problem.  Neither of them 'answers' anything, as they've not actually been defined beyond being that which is needed to solve the anomalies.
 

Offline graham.d

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Does dark matter have structure?
« Reply #7 on: 20/06/2010 13:29:47 »
What you said is true, Lee, but then that is ofetn the way scientific progress is made. Anti-matter, and in particular the positron, was theoretically proposed long before its discovery.
 

Offline tommya300

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Does dark matter have structure?
« Reply #8 on: 20/06/2010 17:34:09 »
In a vacuum of space, having a hypothetical glass, half full or half empty, either portion has to have something occuping that other particular area. Since math does not explain absolutely, things can be piled higher and deeper, fudge factors are acceptable if the majority vote of the committee can agree.

LeeE has made a good point.
« Last Edit: 20/06/2010 17:36:43 by tommya300 »
 

Offline Andrew P

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Does dark matter have structure?
« Reply #9 on: 20/06/2010 18:12:33 »
There's my take on the first question in this thread in the next Naked Astronomy podcast, but it more-or-less agrees with Soul Surfer's logic. (I wrote it independently, honest!)

As to not requiring dark energy/dark matter any more, I've written a critical evaluation of that claim over in the other thread.


Monthly astronomy podcasts -- newbielink:http://www.thenakedscientists.com/astronomy [nonactive]
 

Offline yor_on

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Does dark matter have structure?
« Reply #10 on: 28/06/2010 22:21:20 »
That one was really interesting tommya300 :)

"Clara Moskowitz, senior writer at Space.com wrote:Instead of using Jupiter as a calibration source, the way the WMAP team did, Shanks and Sawangwit used distant astronomical objects in the WMAP data itself that were emitting radio light.

"When we checked radio sources in the WMAP background, we found more smoothing than the WMAP team expected," Shanks told SPACE.com. "That would have big implications for cosmology if we were proven right."

If this smoothing error is larger than thought, it could indicate that fluctuations measured in the intensity of the CMB radiation are actually smaller than they originally appeared. The size of these fluctuations is a key parameter used to support the existence of dark matter and dark energy.

With smaller ripples, there would be no need to invoke exotic concepts like dark matter and dark energy to explain the CMB observations, Shanks said. The researchers will report their findings in an upcoming issue of the journal Monthly Notices of the Royal Astronomical Society."

The paper published is here.
And this one have a discussion on it too, explaining the idea in some detail.
 

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Does dark matter have structure?
« Reply #10 on: 28/06/2010 22:21:20 »

 

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