All Questions
Tagged with cosmology dark-matter
265
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Gravitational halos made of neutrinos...?
I have been recently interested in how halos made of standard model particles could be formed and behave.
After asking some questions in this site, I was told about how neutrinos could form such halos....
- 2,466
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1
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68
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If dark matter is axion particles, how did such light particles slow down?
One candidate for dark matter is axions and there is tentative experimental evidence for their existence.
Axions are very light, most models weigh them in at tiny fractions of an eV. It seems like ...
- 6,531
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1
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250
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What's the meaning of 'cold' in the CDM model?
On Wikipedia, it says
In cosmology and physics, cold dark matter (CDM) is a hypothetical type of dark matter. According to the current standard model of cosmology, Lambda-CDM model, approximately 27% ...
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Test of the primordial black hole solution to dark matter
One of the ideas that might solve some of the dark matter problem are the existence of many small black holes. There is evidence, in principle, for the existence of these small black holes via the ...
- 1,420
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Why do people say that the $\Lambda$-CDM model has six independent parameters?
The Wikipedia article on the $\Lambda$-CDM model says that the model has six "independent parameters". It also says that the model has several "fixed" parameters and several "...
- 48.3k
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149
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Does neglecting dark matter solve the Hubble tension?
If the total mass of the universe is smaller than estimated by neglecting the gravitational pull of dark matter, the estimated expansion rate should be greater.
Does this consideration in the CMB ...
- 466
1
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1
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124
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What if gravitation was the only force? [closed]
This is a follow up of Interactions within constituents of dark matter .
I wonder about dark matter, and, naturally, compare it with our observable world.
If gravitation would be the only force acting ...
- 970
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110
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Is the amount of dark matter per galaxy the same as you look back through time (further away from earth)?
In the hope that it may inform us about the development/evolution (if any) of dark matter over time, are there any differences (eg. in structure or concentration) in the dark matter at large radial ...
- 351
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"Penrose Functional Degrees of Freedom" ( PFDoF) as a source of dark mass
In his book "Fashion, Faith, and Fantasy in the New Physics of the Universe" Sir Roger Penrose mention ( referring to his older works and specially Penrose-Hawking Theorem) the possibility ...
- 2,053
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3
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144
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Why doesn't frozen-out dark matter annihilate later during structure formation?
The so-called freeze-out of dark matter is based on a homogeneous description. However, in the later stages of the universe, where structures form, it seems very likely that the reaction rate would ...
- 619
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General Relativity "doesn't quite work" without dark matter?
I am taking an astrophysics course, and my astro professor said that "we need to introduce dark matter because Einstein's general relativity doesn't quite work without it".
I wanted to ...
- 303
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108
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Is Dark Energy Taking Over?
First question, trying to keep it simple 😃
Because it's constant it grows in magnitude as the universe expands, whereas normal matter does not? Is this accurate as far as we know?
- 11
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48
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Galactic Rotation Curves
While researching rotation curves, I've noticed a variety of velocity behaviors in different galaxies. In some, the velocity decreases, in others, it remains relatively constant, and in some cases, it ...
- 19
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1
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133
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Theoretically, is it feasible for the dark matter density to be constant and homogeneous, as dark energy is, and the two to be related?
I know that currently dark matter and dark energy are separate things, not related and one not deriving from the other. But if both are included in a generalized gravitation theory, the picture can ...
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183
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Does NFW profile work for any galaxy?
We use Navarro–Frenk–White (NFW) to calculate Dark Matter (DM) density. Can we use it for DM halo in any galaxy or is it used only for Milky Way (MW)?
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