Matter not observed directly but inferred to exist based upon its gravitational effects

learn more… | top users | synonyms

5
votes
1answer
59 views

What do the latest FERMI results say about dark matter?

There was an announcement at a recent UCLA symposium on dark matter by the FERMI collaboration which hints at some evidence of dark matter. The results aren't yet published, but the symposium news ...
5
votes
1answer
140 views

Why doesn't the dark matter halo co-rotate with the luminous disk?

What keeps it from falling into the center if not angular momentum?
5
votes
0answers
56 views

Why hasn't warm dark matter replaced cold dark matter as the standard model of cosmology?

The $\Lambda\rm CDM$ (cold dark matter with cosmological constant) is the current standard model of cosmology because the model comes with a long list of phenomena successfully explained by it. ...
4
votes
2answers
663 views

Is cold dark matter made of Higgs bosons?

"Stable Higgs Bosons - new candidate for cold dark matter", by Yutaka Hosotani Has the hypothesis in the above article been proved? What about WIMPs?
4
votes
5answers
216 views

Is dark matter around the Milky Way spread in a spiral shape (or, in a different shape)?

Dark matter doesn't interact with electromagnetic radiation, but it, at least, participates in gravitational interactions as known from the discovery of dark matter. But does dark matter exist in a ...
4
votes
2answers
633 views

How much light is there in space and how heavy is it?

Our night sky is filled with stars. On a dark night a significant fraction of the sky is light. This light, we are told, has been in transit for many millions of years. There must therefore be quite a ...
4
votes
3answers
202 views

Could Dark Matter particles that don't couple to quarks or leptons have been produced?

With what we know about physics, is it possible that when the universe 'began', around when quarks and leptons were produced, another particle, which doesn't couple to either quarks, leptons or ...
4
votes
2answers
311 views

Sterile Neutrinos as Dark Matter

There has been recent activity by astrophysicists to determine whether a fourth flavor of neutrino, a sterile neutrino, exists. It would likely be more massive than electron, muon or tau neutrinos. ...
4
votes
2answers
946 views

Does Dark Matter interact with Higgs Field?

Dark matter does have gravitational mass as we know from its discovery. Does it have inertial mass?
4
votes
2answers
373 views

Sparticles: Relationship to supersymmetry and dark matter?

I was attempting to read this paper after watching a show with Brian Greene. As I understand it, sparticles are a prediction of supersymetry, so I was wondering: Wouldn't the discovery of ...
4
votes
3answers
127 views

Proportion of dark matter/energy to other matters/energy at the beginning of the universe?

What was the proportion of dark matter/energy to other matters/energy at the moments after the beginning of the universe (standard Big Bang model)?
4
votes
2answers
624 views

What is currently incomplete in M-theory?

As it is, what is currently and seemingly incomplete in M-theory? One example I can give is explaining dark matter proportions and.. how do we perceive the world as 4-dimensional. Thanks everyone.
4
votes
1answer
138 views

What are wimpy particles?

Can anyone give a brief overview of what a wimpy particle is?
4
votes
1answer
224 views

How much does electromagnetic radiation contribute to dark matter?

EM radiation has a relativistic mass (see for instance, Does a photon exert a gravitational pull?), and therefore exerts a gravitational pull. Intuitively it makes sense to include EM radiation ...
4
votes
4answers
228 views

Could dark energy be the effect of gravity at great distances?

This may be a silly question, but is it possible that dark energy and gravity are related to each other? Space-time is deformed everywhere in space by objects with mass. The more massive the object, ...
4
votes
1answer
110 views

Mass density of dark matter in solar system near us

What is the approximate mass density of dark matter in our solar system at the radius of the Earth's orbit? I would like some idea of the mass of dark matter going through each cubic meter of ...
4
votes
1answer
214 views

Does the dark matter halo rotate with the galaxy?

If the dark matter halo is stationary related to the arms of the galaxy then tidal effects should slow the galaxy rotation. If it rotates with the normal matter in the galaxy then shouldn't it ...
4
votes
1answer
86 views

Vacuum polarization of dark matter candidates

Can a dark matter particle (axions, for instance, but the question applies to any valid candidate for dark matter) induce QED vacuum polarization effects even if being electrically neutral and with no ...
4
votes
1answer
385 views

What is the formal definition of spin-independent vs. spin-dependent scattering?

In the search for WIMPs as the dark matter particle, there is an important distinction between spin-independent and spin-dependent scattering. Roughly, WIMPs scattering from nucleons through a ...
4
votes
0answers
37 views

Need help on Springel model for galaxy dynamics

I would like to have help about the response of the dark matter profile in the Springel galaxy dynamics model ( from the paper Tidal tails in CDM cosmologies(NB: Arxiv pre-print)) Here's the part of ...
4
votes
0answers
55 views

What are the reasons why dark matter above the TeV scale appears to be ignored experimentally?

I understand that sub-TeV-scale dark matter would fit nicely with TeV-scale SUSY, but are there any other reasons for the large experimental blind spot between TeV-scale WIMPs and the much larger ...
3
votes
3answers
233 views

How much of the universes mass is bound up in photons traveling between stars?

I was watching a Scott Manley video on youtube and he mentioned that the Sun was loosing 4 million tons of mass a second as it converts to energy. With a few trillion trillion stars also converting ...
3
votes
2answers
223 views

If dark matter is a new type of particle, what does that imply?

My understanding is that dark matter cannot be (or is at least highly unlikely to be) an exotic form of any known particle. On the other hand, articles about particle accelerators seem to say that the ...
3
votes
1answer
44 views

What happens when astronomical bodies made up of Dark Matter collapse or collide?

Does dark matter not produce heat or radiation after a collision etc? Or, we detect radiations having no generators?
3
votes
3answers
232 views

Assuming SUSY is found to be incorrect, what would then be the most compelling candidates for dark matter?

From what I've read, the only remaining candidates appear to be either sterile neutrinos or MOND (MOdified Newtonian Dynamics -- it does seem to keep changing.) Did I miss anything else plausible?
3
votes
2answers
286 views

Dark Matter 'Stars'

I'm aware that the Milky Way has a dark matter 'halo' around it, presumably a spherically symmetric distribution. But I'm completely ignorant regarding the theories explaining dark matter... Is there ...
3
votes
2answers
173 views

Dark matter: degrees of freedom

I'm afraid this question could sound a little too vague. I don't even know if dark matter (DM) can be genuinely described by quantum field theory, or if quantum field theory should be somehow ...
3
votes
3answers
352 views

Theory that gets rid of dark matter/energy

Is there any physics theory that either groups together gravity and dark energy/dark matter or eliminates dark energy/dark matter by modifying standard understanding of gravity or any force? If so, ...
3
votes
2answers
283 views

Why is the dark matter density profile within the solar radius (and local density) uncertain?

It seems that we know the rotation curve inside the sun's galactic orbit fairly accurately. Then wouldn't we be able to just take the derivative* of this to get the DM density profile at smaller ...
3
votes
4answers
217 views

Possibility for radiation in dark matter that is not interactive with regular matter?

Definition: Radiation in this case does not refer to electromagnetic radiation. It refers to any kind of emission of energy, even energy that does not interact with regular matter. Just like dark ...
3
votes
1answer
97 views

What determines the shape of the WIMP cross-section vs mass limit curves?

In figure 5 of http://arxiv.org/abs/arXiv:1310.8214 (PDF: http://arxiv.org/pdf/1310.8214v1.pdf), the experiments all seem to reach the lowest cross-sections when the WIMP is in the $40-100\, ...
3
votes
2answers
122 views

Orbits within a $-\vec{r}$ field

Let's say that we have a cold dark matter theory, so we imagine weakly interacting particles. Now, let's say that one of those dark-matter particles has a rare interaction while traveling through the ...
3
votes
1answer
60 views

Do alternate theories for Dark Matter (like MOND) explain it's effect on gravitational lensing?

For a long time, I was sceptical about the evidence for dark matter. To me, it seemed like a pretty big leap to make when we have no idea whether or not our current models of gravity should apply ...
3
votes
1answer
57 views

Interpretation of the WIMP annihilation cross section graph

I have some trouble in the interpretation of the WIMP cross-section annihilation versus their mass. I understand that the lines represent a upper bound on the cross section from the observation. ...
3
votes
2answers
109 views

can we have a parallel earth made of dark matter?

In the sense that the two planets move together and has intelligent beings with their own forces and particles, but they just do not interact with (are invisible to) us?
3
votes
1answer
332 views

Difference between baryonic, inertial and gravitational mass? (and relation to dark matter)

Inertial mass: determined from Newton's f = ma Gravitational mass: determined via Newton's law of gravity Baryonic mass: sum of mass of all baryons. Which ones ...
3
votes
1answer
94 views

missing dark matter?

A recent arXiv article measures the variation of gravitational potential in a local region around the solar system, and from that it tries to infer the mass density. Are there any valid ...
3
votes
2answers
280 views

If matter creates space, shouldn't there be experimentally detectable consequences?

Ernst Mach, a man to who influenced Albert Einstein significantly in his approach to relativity, did not quite seem to believe in space as a self-existing entity. I'm pretty sure it would be correct ...
3
votes
2answers
84 views

How does the friedmon solution to Einstein's equations resolve paradox of bounded infinities?

This article talks about a potential explanation of dark matter based on something called the "friedmon." I have no interest in the dark matter question, but the article has made me curious about ...
3
votes
1answer
123 views

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 ...
3
votes
0answers
36 views

Active-sterile mixing for KeVins

People sometimes talk about KeV mass sterile neutrinos as a warm dark matter candidate. I think they call them KeVins (horrible name btw). Now, In order for it to be a good dark matter candidate it ...
3
votes
0answers
40 views

Which cosmological dark matter theory is most compatible with current particle physics?

This occurred to me while I was writing Why hasn't warm dark matter replaced cold dark matter as the standard model of cosmology? but I think this deserves a question of its own. The background ...
3
votes
0answers
56 views

Dark Matter and Modified Gravity

Could someone please explain briefly or refer me to an article or manuscript that shows how f(R) modified gravity theories can be used to explain the problem of Dark Matter, particularly Galaxy ...
3
votes
0answers
24 views

Does dark matter get drawn into black holes? [duplicate]

Would dark matter get drawn into a black hole? Also, could enough dark matter be concentrated to create a "dark black hole"?
3
votes
1answer
60 views

Neutrino Nuclei Coherent scattering and the Dark Matter lower wall

Suppose that current and new forthcoming dark matter direct detection experiments find no evidence of Dark matter events and exclude interactions of hypothetical DM particles (like LSP or similar) in ...
2
votes
1answer
296 views

Dark matter a medium for light propagation

Is dark matter a candidate to fill void left by luminiferous ether as a medium for light travel?
2
votes
2answers
418 views

Dark matter and dark energy [duplicate]

Possible Duplicate: Dark matter references I have recently read about dark matter and dark energy, and why physicists think it must exist (dark matter: mass of galaxies are far bigger than ...
2
votes
2answers
381 views

Wouldn't the presence of dark matter slow the expansion of the universe?

If there is a huge element of dark matter in the universe, wouldn't this extra gravity prevent the accelerated expansion of the universe?
2
votes
4answers
158 views

Dark matter and tides

As I understand, "dark matter" is what they call a theoretical substance which is only known by it's influence upon velocity curve of the galaxy. If indeed the gravity of "dark matter" is so strong ...
2
votes
2answers
343 views

Is Dark Matter evenly spread out in the universe?

Is Dark Matter evenly spread out? If no, could we ever find a correlation between the amount of dark matter and matter in a specific place?