Physics Stack Exchange
Physics Stack Exchange

Questions tagged [dark-matter]

Questions about astrophysical observations, experimental searches, and theoretical models related to dark matter and its quanta.

The astrophysical dark matter outweighs our usual ("baryonic") matter 5:1. There are a wealth of independent cosmological and astrophysical observations that all support this conclusion; the most important examples are

The nature of dark matter is unknown, and significant experimental effort is devoted to identifying the quanta of dark matter. Most notably this includes

  • precision gravitational observations of astrophysical systems
  • so-called "indirect" astronomical searches for dark matter annihilation or decay products
  • searches at colliders for particles that might be related to dark matter and
  • the so-called "direct" searches for scattering or other interactions of dark matter with laboratory-scale experiments.

Notable hypotheses for dark matter quanta include Axions, WIMPs, and sterile neutrinos. Questions related to these observations, experimental methods, or theoretical models should be tagged with dark-matter.

903 questions
18
votes
1 answer

Distribution of Dark Matter around galaxies

It is well-known that measurements of the velocity profile in galaxies are not compatible with Newtonian laws. A way to circumvent the problem is to assume that galaxies are surrounded by a spherical halo of Dark Matter. The density of mass of this…
Christophe
  • 3,548
13
votes
5 answers

Is Dark Matter expected to be equally distributed in our solar system?

If dark matter winds up being roughly equally distributed in our solar system would this mean it has no net gravitational influence? Furthermore, do we expect dark matter to be less dense out in intergalactic space? Might this be because normal…
Alex
  • 5,973
12
votes
3 answers

What exactly is 'Dark Matter'?

There are many documentaries, forums, blogs and more dedicated to Dark Matter. I have been frantically searching for an answer to my question however none of my sources have clarity to the matter of hand. I would really love a clear explanation to:…
user71793
12
votes
1 answer

Could the dark matter sector be boring?

People always talk about finding good dark matter (DM) candidates of beyond Standard Model (SM) theories. To be a proper candidate the particles should not decay into the SM particles and could potentially be weakly interacting mass particles…
JeffDror
  • 8,984
9
votes
7 answers

How do we know that dark matter is dark?

How do we know that dark matter is dark, in the sense that it doesn't give out any light or absorb any? It is impossible for humans to be watching every single wavelength. For example, what about wavelengths that are too big to detect on Earth?
Jonathan.
  • 6,907
  • 18
  • 70
  • 94
7
votes
2 answers

Is this the end of dark matter?

If the paper is accepted for publication, does it mean we don't need the dark matter theory anymore? Or, should I say, it is not dark anymore? "The Radial Acceleration Relation in Rotationally Supported Galaxies" Stacy McGaugh, Federico Lelli, Jim…
user4954
5
votes
4 answers

why can't the missing mass (evidence for dark matter) be matrioshka brains/dyson spheres?

i know that the claim is that nucleosynthesis models say that the observed abundance of deuterium is too high for dark matter to be baryonic, but couldn't deuterium be a waste product of civilizations? you say that postulating civilizations is not…
user1283
4
votes
1 answer

How does Dark Matter form a halo?

Here are the velocity components of the Milky Way (according to Sofue et al. 2013) out to 20 kpc. The vertical axis is $k$ $s^{-1}$. The horizontal axis is $kpc$. The purple line is the rotation curve of all the components. The green line is the…
user32023
3
votes
3 answers

Is Dark Matter really invisible?

From what I understand dark matter is called dark since it cannot be seen in the universe. My question is does it have to be invisible, as in to not interact with light ? Could it be that dark matter interacts so weakly with itself that there is…
Jonathan
  • 33
  • 4
3
votes
1 answer

Why would dark matter collide with sodium iodide?

In my readings of the DAMA/Libra dark matter detector articles, it is said to detect a dark matter particle by seeing light emissions from a sodium iodide crystal ion collision. My question is why would the collision happen if dark matter doesn't…
icedcoffee
  • 33
3
votes
1 answer

Do WIMPs have to interact non-gravitationally with each other or other particles?

I know many collaborations are attempting to detect the interaction of WIMPs with nucleons or with themselves, with the recent result from Ice Cube (http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.110.131302) showing no evidence for WIMP…
Sean
  • 33
3
votes
1 answer

Could dark matter be degenerate?

If dark matter were to be partly composed of fermions (such as hypothetical neutralinos), then could these particles be subject to degeneracy pressure if they were trapped in the potential well of a galaxy? If so, would that make them even harder to…
orange21
  • 33
2
votes
2 answers

Is dark matter due to observational error

It seems to me that the idea of dark matter grew from doppler measurements of the velocities of the outer stars of spiral galaxies. It was assumed that what was being measured was the orbital velocities around the galaxy's center. The mass of a…
William Robert Smith
  • 29
2
votes
2 answers

Why can't dark matter be baryonic?

Here's what I know about dark matter: Astrophysicists realized the movements of galaxies and other astronomical bodies cannot be explained by the gravitational effects of matter known to be there, so either there is a lot of matter missing that…
Jmfig314
  • 117
2
votes
0 answers

Particle dark matter coherent scattering?

Particle dark matter coherent scattering direct searches rely on the scattering of the DM particle off a nucleus (Xe, Si, Ge, NaI etc). The wisdom is this is coherent scattering: so the rate ~atomic mass squared, since $q^2 \approx zero$. Is this…
David Winn
  • 21
1
2 3