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

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Deceleration parameter in a Universe dominated by the cosmological constant

See Deriving the deceleration parameter of a universe whose density is dominated by matter for a derivation of $q_0 = \frac{\Omega_m}{2}-\Omega_\Lambda$ If the universe were $\Lambda$ dominated, ...
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336 views

Is it possible that all “spontaneous nuclear decay” is actually “slow neutrino” induced?

This thought was inspired by a comment from the current leading answer, by @Sentry, to the question Where are all the slow neutrinos? This [slow-neutrino induced nuclear decay] will still be an ...
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2answers
515 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 ...
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83 views

Dark Matter Scattering

I have been attempting to find a general formulae for dark matter scattering off of protons (or other baryonic matter) but with no avail. I took a quick look at solar capture of dark matter but the ...
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199 views

Does Dark Matter Exert The Same Gravitational Force As Ordinary Matter?

I have read through this Wikipedia article on Dark Matter and it contains references to the methods used to demonstrate the existence of dark matter. A galaxy rotation curve is a plot of the ...
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198 views

Are massive gravitons as the dark matter fluid more correct than the notion of WIMPs?

Accepted at APS Physical Review D: Massive gravitons as dark matter and gravitational waves Precursor: Bigravitons as dark matter and gravitational waves The massive graviton is a viable ...
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294 views

Could dark matter/dark energy turn out to be tachyonic?

Today, I was watching the Inexplicable Universe with Neil deGrasse Tyson. He spoke about Dark Matter, Dark Energy, and then he spoke about Tachyons. Naively, I thought what if the reason we can't ...
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63 views

Why is there a matter-dark matter asymmetry?

It is said generally that nature is symmetric. For example if light behaves as both a particle and a wave, then matter must also do so, which turns out to be true. But we find that the Universe ...
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55 views

Could dark matter possibly be anti-matter?

Considering the broken symmetry after the big bang - what I understand as there being a huge surplus of matter and a lesser presence of anti matter - is it possible that dark matter could be anti-...
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2answers
476 views

Could anti-matter collisions be or make dark matter?

I've recently seen that space is or could be a quantum vacuum full of particles like matter and anti-matter appearing and possibly colliding causing in theory the same effects that dark energy has. My ...
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25 views

Expansion Of Universe : On the Basis Of Aether Theory [duplicate]

I would like to ask that in the recent experiment of discovering Gravitational Waves scientists have also found or believe that they have found the evidence of Dark Matter. So if dark matter is made ...
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5answers
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If dark matter only interacts with gravity, why doesn't it all clump together in a single point?

I'm a complete layperson. As I understand, dark matter theoretically only interacts with the gravitational force, and doesn't interact with the other three fundamental forces: weak nuclear force, ...
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Why isn't dark matter just matter?

There's more gravitational force in our galaxy (and others) than can be explained by counting stars. So why not lots of dark planetery systems (ie without stars) ? Why must we assume some undiscovered ...
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Could Dark energy and Dark matter just simply be a warping of spacetime? [closed]

Why do most theories about what Dark energy and Dark matter is make it so that these substances (or not) need to be some kind of undiscovered particle? Would it be possible for Dark energy to simply ...
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38 views

Could dark matter annihilation prolong the stellar era?

I wonder, if we assume that dark matter actually exists, and it is WIMPs, and it's annihilate to fermions and W/Z bozons, which decay/combine into protons, neutrons and electrons and finally recombine ...
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43 views

Is it possible that cosmic ray particles and neutrinos account for a significant portion of dark matter?

Sounds a bit naive but I read somewhere that neutrinos were thought to account for dark matter to an extent and I think Zwicki came up with the idea before cosmic rays were announced (not sure though)....
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57 views

Need help with determining the total 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 ...
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3answers
83 views

Can black holes grow via accretion of dark matter particles?

I'm assuming that the answer to the question in the title is a resounding yes. Since Baryonic matter and dark matter interact via gravitational forces. If this is the case how is information not lost ...
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How did the universe shift from “dark matter dominated” to “dark energy dominated”?

In order to get dark energy to dominate, wouldn't you first need another form of energy to push the expansion until dark energy could dominate? Otherwise I don't understand how the universe could ...
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30 views

Lagrangian Interaction Type and Spin-Dependence

So I'm transitioning from reading particle physics books to the literature, specifically as it pertains to dark matter models. In this case I'm talking about t-channel DM-nucleon scattering. They ...
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71 views

Why is Dark Matter not simply explained by QED

My understanding is that Dark Matter needs to exist to explain the mass of the universe -- that is, all the observable matter in galaxies are not sufficient to explain the gravitational behavior -- ...
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1answer
112 views

Relation between dark matter and supermassive black holes located in the center of galaxies

This research (see press article and technical paper), conducted on 3000 elliptical galaxies (which are typically galaxy merger results), reports finding "distinct relationship between the mass of the ...
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Form factor and EFT form factors for an interaction of a WIMP and a nucleon

On the third paragraph(right column) of page 1 of the paper, http://journals.aps.org/prc/abstract/10.1103/PhysRevC.89.065501, it says, "Because the momentum transfer in the scattering is large ...
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46 views

Do satellite galaxies have the same proportion of dark matter as “ordinary” galaxies

My question is relatively straightforward: Do we know if satellite/ dwarf galaxies contain the same proportion of dark matter to ordinary matter as "regular" sized galaxies? The Milky Way, for ...
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1answer
82 views

Is a nearby parallel universe still in use as an explanation for dark matter?

Is the theory which explains dark matter as the effect of a nearby parallel universe still used as an explanation for dark matter, or does this theory already lie on the pile of forgotten theories?
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Integrated Boltzmann equation for dark matter

In Dodelson's book, the equation for a scattering process $ a + b \Leftrightarrow c + d $ is given as \begin{align} a^{-3} \frac{\mathrm d (n_a a^3)}{\mathrm d t}&=-n^{\text{eq}}_a n^{\text{eq}}...
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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 case?...
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680 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, is ...
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132 views

Relativity and Galaxy Rotation Speed

If time travels slower nearer gravity wells, why can't the galaxy rotation speeds being faster on the outer edges than the inner areas be explained by relativity? What necessitates dark matter?
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42 views

How do funnels hinder (help?) detection of dark matter?

I came across some a new (to me) bit of terminology at a seminar recently. In the context of dark matter scattering off of atomic nuclei (but I think it may apply more generally for any particle ...
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Dark Matter vs. Mass from Kinetic Energy

I was thinking about dark matter, and was wondering if the extra mass due to kinetic energy has been taken into account. Here's what I mean: let's talk about any cosmological object that is known to ...
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1answer
281 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?
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28 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 procedure?...
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45 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 ...
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What's the evidence, if any, for some local concentration(s) of dark matter in some region(s) smaller than a galaxy?

What's the evidence, if any, for some local concentration(s) of dark matter in some region(s) smaller than a galaxy? Galactic-sized - or larger - gravitating halos seem to get all the attention. I'm ...
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5answers
2k views

Dark matter and dark energy references

I've been looking for questions about dark matter, and I've read some very interesting answers. However, I desire too look into it deeply. This is not actually a question. I'm asking the community ...
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1answer
234 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 ...
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1answer
43 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: https://ned.ipac.caltech.edu/level5/Sept11/...
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1answer
232 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. ...
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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 ...
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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 ...
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86 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 ...
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1answer
67 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%, ...
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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 ...
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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 ...
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19 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 ...
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1answer
147 views

Reference request: dark matter and $f(R)$ 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 the galaxy ...
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4answers
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How do we know Dark Matter isn't simply Neutrinos?

What evidence is there that dark matter isn't one of the known types of neutrinos? If it were, how would this be measurable?
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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 ...
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5answers
291 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 matter?...