All Questions
Tagged with cosmology dark-matter
265
questions
1
vote
0
answers
84
views
The 'core-cusp' problem for dark matter halos in larger galaxies
TLDR: Do observations of larger galaxies favour 'cuspy' dark matter halo distributions, as predicted by N-body simulations?
I've been trying to understand the 'core-cusp' problem for dark matter halos ...
- 11
1
vote
1
answer
121
views
Dark matter, MOND or flattened gravitational fields? [closed]
Could there not be a third variant to explain why e.g. long-distance multistar systems rotate faster than Newton's law of gravity suggests?
In addition to the Dark matter hypothesis and MOND then, ...
- 521
0
votes
1
answer
151
views
What if dark matter/energy did not exist?
What if dark matter and dark energy did not exist and were only due to a misinterpretation of the red shift of light or a measurement bias?
What would be the implications/consequences?
3
votes
1
answer
106
views
What happens to objects along spiral galaxy arms over long periods of time?
Observations of spiral galaxies reveal that objects within the same arm of a spiral galaxy move at around the same speeds, regardless of their distance from the center of the galaxy. Conversely, the ...
0
votes
0
answers
24
views
How much gravitational lensing do we see from the Milky Way?
I assume that the Milky Way has a dark matter halo just like any other. If that is the case, if we look at a huge part of our own galaxy, do we actually see the gravitational lensing effect? How ...
- 495
0
votes
1
answer
93
views
Event after big bang that cause dark matter [closed]
When the universe was formed by the Big Bang, what was the event that made some matter visible to us, while some became dark matter?
2
votes
2
answers
205
views
Likelihood of MACHOs being the best candidate for dark matter
Massive compact halo objects ("MACHOs") include a wide variety of hardly detectable bodies such as brown / white / black dwarfs and black holes, to name a few. If we take into account the ...
- 1,616
0
votes
0
answers
50
views
Is the $σ8$ tension in the ΛCDM cosmology evidence that the amount of Dark Matter (DM) in the universe is increasing?
Strong evidence is provided by recent cosmological studies that “clumpiness” in the large scale structure (LSS), as measured by $σ8$, is decreasing (for example, “Hyper Suprime-Cam Year 3 Results…”, X....
- 11
0
votes
0
answers
31
views
Why can't Dark matter be made up mostly of Neutrinos? [duplicate]
It's said that Neutirnos can only make up a tiny fraciton of dark matter.
So why can't Dark matter be mostly made up of Neutrinos?
Why can't there just be a huge number of them?
I suspect myself that ...
- 2,908
1
vote
1
answer
40
views
Could the energy emitted by galaxies contribute to the dark matter phenomenon?
I'm pondering a concept regarding the energy-mass conversion in the context of cosmology, specifically related to the light emitted by galaxies over billions of years.
Einstein's famous equation E=mc^...
- 11
1
vote
1
answer
60
views
Reference: 1+1D paper-model representation of the Lambda-CDM cosmological model
I'm looking for a 1+1D (1 time + 1 space dimension) paper model of the current $\Lambda$CDM cosmological model; if possible, one which somehow respects the scales of geodesic spacelike distances at ...
3
votes
1
answer
119
views
Could a fourth family of quarks and leptons account for dark matter?
In the early universe, could a family of quarks and leptons have formed an electrically neutral particle that is dark matter?
user361671
4
votes
1
answer
270
views
How can black holes possibly drive accelerating expansion of the universe?
(Potentially too broad, but all my questions are related to the paper in question.)
Recently there was an article published in Astrophysical Journal Letters that claims black holes "contribute ...
- 21.4k
2
votes
0
answers
42
views
Did galaxies spin differently 4, 5, 6 billion years ago?
Today I read that the Matter-dominated era ended 4 billion years ago, and now we're in the Dark Energy dominated era.
Obviously, light from galaxies far enough away would be from earlier in the ...
- 121
1
vote
2
answers
143
views
The slowing of expansion in the matter dominated era
On all the graphs of the inflation of the universe, the era dominated by matter is slowing the rate of expansion. With an intuitive explanation (for all you science communicators out there) could you ...
