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

learn more… | top users | synonyms

3
votes
1answer
102 views

What is the difference between the Big Bang Model and the Λ-CDM Model?

If I'm going to write about "The Consensus Model of Cosmology" should I include Big Bang Model or should I go with just the $\Lambda$-CDM Model?
-1
votes
0answers
33 views

Scalar dark matter

I was going through a minimal standrad model which included a real scalar singlet particle that can act as a candidate for dark matter.In that model,It was emphasized that such a scalar particle can ...
1
vote
0answers
27 views

How is mass of observable universe calculated? [duplicate]

How is even mass of earth known ? How do we get to know them? Whilst I was studying about dark matter it was listed about 'mass of observable universe' and density and so on...so what is the ...
0
votes
0answers
22 views

Dark matter from general relativity? [duplicate]

We know that there is dark matter due to the observational orbital velocities and mass to light ratio not matching that of expected ones. However the expected orbital velocities of stars in the Milky ...
-1
votes
1answer
211 views

What is dark matter? Also what is dark energy? I am not duplicating it put just want to write as an article for helping others [duplicate]

Today one of the greatest questions coming up is what is dark matter. also what is dark energy. we don't know much about it still!!! I have tried to bring some light on this question. To prevent ...
1
vote
1answer
41 views

What size of object does the peak of the cosmological power spectrum correspond to?

The title almost says it all, but to flesh it out more, what is the size a sphere corresponding to the peak in the cosmological power spectrum (Figure 2: ...
0
votes
2answers
114 views

Higgs boson and dark matter.

In the standard model the Higgs boson gives the mass to other particles, but in the Universe we know that the 80% of mass is in form of dark matter, that is not constituted by known particles. The ...
0
votes
0answers
14 views

Shouldn't HDM drain photons energy?

Hot dark matter (HDM) would be made from very light, fast moving particles. Such particles could not possibly be gravitationally bound to any structure, but rather would be dispersed all across the ...
4
votes
1answer
61 views

Did LIGO detect dark matter?

Which is the title of this preprint They claim that: We consider the possibility that the black-hole (BH) binary detected by LIGO may be a signature of dark matter. Interestingly enough, there ...
2
votes
1answer
60 views

Where did all the photon energy go?

From the wikipedia page on dark energy, in reference to the total mass-energy of the universe: The mass–energy of dark matter and ordinary (baryonic) matter contribute 26.8% and 4.9%, ...
1
vote
0answers
20 views

What sets the lower mass limit for dark matter dominated structures?

Large galaxies appear to be dominated by dark matter, as do dwarf spheroidal galaxies with masses of perhaps $10^6 M_{\odot}$. But (as far as I'm aware) there is no evidence for dark matter in ...
3
votes
0answers
27 views

Need help with determining the stellar mass using the NFW profile

My review assignment has a question that asks us to use the Navarro–Frenk–White (NFW) profile to find total mass in the galaxy using $$\rho(R)=\frac{\rho_0}{1+\frac{R}{R_c}}$$ then taking a triple ...
1
vote
0answers
18 views

Galactic Rotation Curve Calculation

Can anyone give the list of formulas used for plotting the Galactic Rotation Curves? I mean, is there only the formula for linear velocity or is the formula for the gravitational potential also ...
4
votes
4answers
210 views

Is it possible that dark-matter is composed of a large number of neutrinos from the big bang? [duplicate]

They seem to have all the properties of dark-matter (massive, with no electromagnetic interaction). Could it be that many of the neutrinos produced since the big bang have formed massive neutrino ...
0
votes
0answers
22 views

What are some good papers on the topic of dark matter that you would recommend? [duplicate]

I just finished off my BSc in physics a few months back and looking to learn more on the topic of dark matter. The topic of dark matter combines two of my favourite subjects particle physics and ...
3
votes
1answer
53 views

Questions about shape of dark matter orbits in spiral galaxies

Could someone please describe how are the proposed (calculated) orbits of dark matter? Are they exactly as those of baryonic matter (i.e. spiral), or they are different from those of baryonic matter? ...
5
votes
3answers
669 views

How to explain two possible problems with dark matter

Can someone please answer how dark matter theory resolves/eliminates these two possible problems Dark matter, per my understanding, due to gravity, keeps moving, and due to its non-interactive ...
-3
votes
5answers
277 views

Is dark matter really there? [closed]

Dark matter has been proposed to explain two phenomena - Uniform velocity curve of spiral galaxies Observed gravitational lensing. If something explains these two, would we still need dark ...
0
votes
2answers
94 views

What is the amount of dark energy in the Universe, in joules?

I'm toying with an idea, and need absolute amounts of dark energy. I'd also like the same for dark matter. If these values are not estimated, why not?
4
votes
1answer
72 views

Was the matter-energy content of our universe always distributed in the same ratios?

Currently, Dark energy (68.3%) and Dark matter (26.8%) together constitute about 95.1% total matter-energy content of the universe while only 4.9% is ordinary baryonic matter. Was this always the ...
1
vote
1answer
78 views

Virtual particles, gravity, and dark matter? [closed]

In Hawking's radiation, virtual particles respond to intense gravitational tidal forces with pairs being ripped apart. One crosses the event horizon and the other escapes. On the other hand, in ...
1
vote
2answers
71 views

Could dark matter be like ether?

Could dark matter (and dark energy) be proven wrong as ether was? Is it possible that we actually misunderstand how gravitation works, and that our current model is wrong? The fact that we need an ...
1
vote
0answers
30 views

How to determine the size of other galaxy's/The dark matter problem

From what i understand there are two methods (well as far as i know) to determine how much mass there is in a distant galaxy. First, Luminosity. By measuring the amount of light produced from a ...
1
vote
1answer
46 views

Large scale structure of the universe

I have read of two seemingly straightforward explanations that give reasons for the inhomogeneity of the large-scale structure of the universe (i.e. why stars / galaxies formed where they did) One is ...
1
vote
0answers
43 views

Requesting explanation for why dark matter evidence is not explained by special relativity [duplicate]

Good afternoon. I'm doing research for a possible hard science fiction project and was looking up information on dark matter. Wikipedia--hardly an authoritative source, I know--mentions that the ...
3
votes
4answers
181 views

What allows us to assume spacetime is flat when no normal matter is present?

Dark matter causes a bend in spacetime. We see this through gravitational lensing. But what allows us to assume spacetime is flat when no normal matter is present? Why can't we say that dark matter ...
0
votes
1answer
38 views

Is dark matter particle affected by weak interaction too?

Neutrino is affected by weak subatomic force and gravitational force and just like dark matter they don't easily interact with matter, if dark matter cannot be affected by the weak interaction how ...
4
votes
1answer
59 views

Is dark matter (if any) the reason why we even exist?

If we were to model a universe without any dark matter in it, would stars and other large scale cosmic structures (galaxies or clusters) form in timescales similar to our universe? Or would they never ...
0
votes
0answers
35 views

Dark Matter and Equivalence Principle

Dark Matter effects show up in galaxies. Why isn't it considered as a violation of equivalence principle instead of assuming all these extra non-interacting particles as gravitational mass and ...
3
votes
0answers
102 views

Dark matter “hair” flowing through the earth

Gary Prézeau of NASA's JPL has done some calculations of how dark matter might be focussed by the Earth's gravitational field (publication preprint), and the results show some remarkable hairy ...
0
votes
1answer
94 views

How to distinguish between dark matter and dark antimatter?

I know dark matter exists to account for the missing mass otherwise many galaxies should have already fall apart, unfortunately they seldom interact with other matter and perhaps even their own kind ...
3
votes
2answers
125 views

How is dark matter detected?

What methods do we use to detect Dark Matter? If I understand correctly, due to lack of electromagnetic interaction it should be able to phase through normal matter nearly like through void - since ...
1
vote
2answers
55 views

How would superpartners explain dark matter? (Supersymmetry)

This is probably very basic but I can't quite find the answer in other questions. As I understand it we are hoping to create supersymmetric particles at the LHC (in this second run) and these ...
1
vote
2answers
108 views

Should dark matter play an important role in designing a quantum theory of gravity?

Since dark matter "accounts" for most of the matter of the universe, and its effect are inferred from the gravitational effects, should it play an important role in designing an unified theory between ...
4
votes
4answers
245 views

Relation of General Relativity to Dark Matter and Dark Energy

I was reading an elementary book on dark matter (in fact, a historical perspective) and there were mentioned how the scientific community react to the idea of dark matter proposed as a solution to ...
-1
votes
4answers
245 views

Why is “dark matter” theory accepted? Why wasn't general relativity rejected?

Dark matter was made up to account for unexplained effects such as gravitational lensing, the speed of expansion of the universe, or the rate of rotation of certain galaxies. However, as Feynman ...
0
votes
1answer
58 views

What is the DAMA dark matter detector reporting and why does no-one else believe them?

I understand DAMA is a dark matter detector but I don't understand how it works, and what it's seeing. They claim to have a seasonal variation in their signal which is supportive of a certain type of ...
0
votes
0answers
23 views

Does matter shrink due to energy radiation and does it have anything to do with dark matter and dark energy?

Is matter shrinking? Is shrinking the cause of concentrated dark matter that makes up matter moving from concentration to unconcentration. Does dark energy and expansion of the universe come from this ...
1
vote
1answer
64 views

Looking for a specific theory concerning Dark Matter [closed]

I am looking for the name of a theory positing that "empty" space itself is not empty, but has substance, and that "fabric" or "substance" is actually what we call Dark Matter. In theory, dark matter ...
2
votes
0answers
47 views

How sensitively can we detect a moon-sized mass of dark matter?

Suppose there is an object with the mass of the moon made entirely of dark matter. Suppose that somehow, it has the same mass density as the moon. By dark matter I mean matter that does not interact ...
3
votes
0answers
35 views

Why is the galaxy's dark matter halo a sphere instead of a disk? [duplicate]

I understand that the galaxy is disk shaped because it has a substantial total angular momentum (if that's the right term). If the dark matter halo is a sphere, does that mean that its total angular ...
2
votes
2answers
185 views

Does Newtonian physics work on a galactic scale?

I'm currently working on a simulation that aims to use Newton's Law of Gravitation to simulate how a galaxy behaves gravitationally. While I haven't gotten the simulation finished yet, I have had a ...
2
votes
2answers
103 views

ΧΕΝΟΝ1Τ: Will it fail to discover DM? Why is it necessary? What benefits for society?

Since a new experiment (ΧΕΝΟΝ1Τ) will take place in Italy to directly detect WIMPs and since there are already many experiments trying to do the same or something similar (e.g. CERN LHC, LUX, CoGent, ...
-3
votes
1answer
211 views

Gravitational constant, $G$, What if it is not Constant?

The question is on title; What if Gravitational Constant, $G$, is not constant? Let's skip all the local consequences if it would suddenly change, like asked here; Can gravitational constant be ...
0
votes
0answers
36 views

Direct vs indirect detection of dark matter

Background There are two categories of searches for dark matter. Direct Detection via reproducible experiments Indirect detection Detection of e.g. annihilation signal from astrophysical sources ...
1
vote
0answers
24 views

Do clouds of dark matter cool and contract?

If dark matter participates in the weak interaction, clouds could cool via thermal neutrino radiation...? And even if does not participate in the weak interaction, clouds should contract via ...
0
votes
1answer
58 views

Why should we expect dark matter with weak scale masses?

The WIMP "miracle" is often used to motivate WIMPs: that a WIMP with a weak-scale mass naturally freezes out of thermal equilibrium after the big bang with the right relic abundance. I understand the ...
2
votes
2answers
161 views

Magnetic monopole bound state

Magnetic monopole (mm) bound states Background: I'm an experimentalist, simple equations are appreciated. (Complicated equations are fine, as long as I can ask questions.) This is one of many ...
2
votes
0answers
206 views

What would happen if all dark matter disappeared?

This is related to this question which provided evidence about dark matter, and this question which asked what would happen if dark energy started disappearing. This question assumes that dark matter ...
0
votes
1answer
37 views

Can Dark Matter be light and cold at the same time?

In most of the papers that I encounter, the mass range for Dark matter is generally taken to be 1-1000 GeV. Is it possible that dark matter is of the order of few MeV? What observation is violated in ...