- #1
RyanH42
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Is Dark matter homogenenius in Universe ? I don't think so but I don't know any idea about it.
Thank you
Thank you
Is Dark matter homogeneous in Universe?
- Thread starter RyanH42
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In summary: It will take you to a scientific paper that discusses the distribution in more detail.In summary, dark matter is generally found in more diffuse distributions than baryonic matter, due to the lack of dissipative interactions. This is likely responsible for the large-scale structure of baryonic matter through the formation of gravitational wells in the early Universe.
- #2
Bandersnatch
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No, it isn't. It clusters like normal matter, but in more diffuse distribution due to the lack of dissipative interactions. You get, for example, halo-like structures around galaxies.
Try googling 'dark matter distribution', and you'll get plenty of hits to scientific papers, popular articles and images mapping the distribution. IIRC, some of the free planetarium software out there also allows viewing DM distribution as it's known today (Digital Universe should have that functionality, I think).
Try googling 'dark matter distribution', and you'll get plenty of hits to scientific papers, popular articles and images mapping the distribution. IIRC, some of the free planetarium software out there also allows viewing DM distribution as it's known today (Digital Universe should have that functionality, I think).
- #3
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The funny thing is that dark matter structure was likely responsible for the large scale structure of baryonic matter through the formation of gravitational wells in the early Universe. Without dark matter, there would be significantly less structure on large scales.
- #4
- 18,809
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Just to add to what has already been said, on VERY large scales, dark matter, like regular matter, is taken to be homogeneous, or more technically appropriate, "isotropic" but not in scales such as galactic clusters (which can be REALLY REALLY big by human standards)
- #5
RyanH42
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I am talking about very very large scales.Not small distances.Is phinds idea true ?
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Do you think I"m making it up?RyanH42 said:
How large is "large" to you?
- #7
RyanH42
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Like universe radius distance.
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The universe HAS no "radius" so that doesn't make any sense.RyanH42 said:
If you mean the radius of the observable universe (as opposed to "the universe") then yes it absolutely is isotropic.
- #9
Bandersnatch
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Here's a 1 billion ly across mapped region of the universe.
(taken from: http://www.cfht.hawaii.edu/News/Lensing/)
Brighter regions are more dense concentrations.
You can see that while a filament-like structure is still visible, it is approximately homogenous - there are no clearly defined voids and overdense regions. You can easily extrapolate this to an even large scale.
The bottom line is: both dark and visible matter are approximately homogeneous on large scales.
And once again, google is your friend. That picture took maybe 5 seconds to retrieve.
(taken from: http://www.cfht.hawaii.edu/News/Lensing/)
Brighter regions are more dense concentrations.
You can see that while a filament-like structure is still visible, it is approximately homogenous - there are no clearly defined voids and overdense regions. You can easily extrapolate this to an even large scale.
The bottom line is: both dark and visible matter are approximately homogeneous on large scales.
And once again, google is your friend. That picture took maybe 5 seconds to retrieve.
- #10
RyanH42
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Isotrophic ok What about homogeneius ?.Or Isotrophy universe makes also homogeneius ?
- #11
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You'll have to define your terms. The sand on a beach seems VERY homogenous looked at from a distance but if you hold a few grains in your had it doesn't look homogeneous at all.RyanH42 said:
- #12
RyanH42
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I am talking about large scales.
In the the universe ,dark matter distrubition homogeneius and isotrophic at the scale of observable universe radius ?
In the the universe ,dark matter distrubition homogeneius and isotrophic at the scale of observable universe radius ?
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You STILL have to define what YOU mean by "homogeneous". How much granularity is OK to still call it homogeneous?RyanH42 said:
- #14
RyanH42
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At least Homogeneius like the baryonic matter distrubition
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Yes, it is as isotropic as normal matter. They tend to go together at roughly the same ratio (about 5:1) in clumps we call galaxies.RyanH42 said:
- #16
Bandersnatch
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@phinds: be mindful of the terms you use. Homogeneity and isotropy are not synonymous, even though the large-scale distribution of dark as well as baryonic matter satisfies both.
- #17
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Right ... that's why I've tried to stick with isotropic and have encouraged the OP to define and understand his terms and I have been specific about how I am using "homogeneous" (see post #11)Bandersnatch said:
- #18
RyanH42
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Thank you again.
- #19
Omega0
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Could you help me here? I am not interested in an image. I would like to have access to concrete data. Thanks!Bandersnatch said:
- #20
Bandersnatch
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Follow the link below the picture.Omega0 said:
1. What is dark matter and why is it important?
Dark matter is a type of matter that is believed to make up about 85% of the total matter in the universe. It does not interact with light and therefore cannot be directly observed, making it difficult to study. However, its presence is inferred through its gravitational effects on visible matter such as stars and galaxies. Understanding dark matter is important because it plays a crucial role in the formation and evolution of the universe.
2. How is dark matter distributed in the universe?
Current theories suggest that dark matter is distributed in a homogeneous manner throughout the universe. This means that it is evenly spread out, with the same density in all regions of the universe. However, there are still ongoing studies and debates about the exact distribution of dark matter.
3. What evidence supports the idea of homogeneous dark matter?
Observations of the cosmic microwave background radiation and the large-scale structures of the universe provide evidence for the homogeneity of dark matter. These observations suggest that dark matter is distributed in a uniform manner on a large scale, with variations only on smaller scales.
4. Are there any exceptions to the homogeneity of dark matter?
While the current understanding is that dark matter is homogeneous, there are some studies that suggest there may be small variations in its distribution. These variations are still under debate and further research is needed to fully understand the distribution of dark matter in the universe.
5. How does the homogeneity of dark matter affect the formation of galaxies?
The homogeneity of dark matter is a crucial factor in the formation and evolution of galaxies. It provides the gravitational pull necessary for the formation of structures, such as galaxies and galaxy clusters. Without the presence of dark matter, the universe would look very different and the formation of galaxies would not be possible.
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