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

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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? ...
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103 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 ...
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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 ...
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57 views

Could there be a dark matter planet? [duplicate]

Since dark matter is gravitationally "charged", by which I mean it has mass and attracts things, could it bunch together to form a planet?
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124 views

Did these scientists actually detect dark matter?

I came across an article in The Guardian (definitely not the best source for science, but that's why I'm asking this question) that said that a team of scientists may have detected dark matter ...
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50 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 ...
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33 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"?
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162 views

Partial waves and the velocity expansion of a scattering cross section

I'm confused about the relation between the velocity expansion of a scattering cross section and the angular momentum (partial wave) expansion. For example, for dark matter annihilation, we write $\...
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100 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 ...
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920 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?
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505 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?
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370 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 ...
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384 views

Where is all the Dark Matter? Theoretical Question

In my Physics Class we had to look into possible areas where Dark Matter could be "hiding." Such as Black Holes and so on. Dark matter really can be "seen" through its gravitational effects, and we ...
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758 views

Redshift of light in dark matter

Following Edwin Hubble, it is widely believed that the universe is expanding, which is based on the red-shift of light from distant objects. Can dark matter cause light to be red-shifted and make it ...
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89 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 ...
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419 views

Why can't dark matter be baryonic? [duplicate]

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 ...
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184 views

What happens when Dark Matter comes in contact with the event horizon of a large Black Hole

Josh Hill, 9, Oakdale Elementary has always talked Theory of Relativity and Astrophysics etc., I can answer most but lately he has stumped me and has been begging me to ask a pro, so here it is.... "...
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94 views

Neutrino mass as counted in Dark Matter

If I try to add up neutrino masses (let's assume 1 eV rest mass equivalent each) to count as DM, do I use the rest mass or relativistic mass?
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399 views

Could dark energy be heat? Could dark matter be stuff that is not seen because of its refraction limits?

Heat has to go somewhere. Would the light and heat of the stars in the universe amount up to being dark matter ...and dark energy ... Dark matter would just be small pieces of stuff. Dark energy ...
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79 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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160 views

Lagrangian point or dark matter?

We know that spiral galaxies spin in a way such that we have to assume that dark matter is responsible for the extra mass required to do so. My question is, can Lagrangian points (L1 and L2) be used ...
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313 views

Dark matter and QFT

My understanding is that the particle is a somewhat artificial notion in QFT (see: Quantum Mechanics: Myths and Facts), and that in general it is possible for a quantum field to have unstable ...
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266 views

What about the neutron stars with CMB temperature as dark matter?

Inspired by How do we know that dark matter is dark? and What is the temperature of the surface and core of a neutron star formed 12 billion years ago now equal to?
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43 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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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, ...
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81 views

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 ...
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325 views

Relativistic Mass and Dark Matter

In a question here Ron Maimon comments that "relativistic mass makes gravity, not rest mass." If so, does that mean that the faster that stars orbit the galaxy the larger the relativistic mass of the ...
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978 views

Could M-Theory explain dark matter as well as dark energy?

Is it possible that M-Theory provides a solution to the mystery of dark matter and dark energy? The idea of dark matter and dark energy is that there is some inexplicable source affecting our ...
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117 views

Can observations of cosmic super voids teach us anything about time, dark energy, or dark matter?

Can observations of cosmic super voids teach us anything about... Time - If gravity affects time is there a chance we could gain any further information from studying a region with lower than ...
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133 views

WIMPs - would they be charged?

I'm no expert in this stuff, it's just a hobby to me, but I've been reading up on the WIMP theory a bit - layman articles, not published research. From Wiki on Dark Matter: It also cannot ...
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73 views

x-rays from dark matter accretion into a supermassive black hole?

I understand that accretion of normal matter into a super-massive black hole leads to x-ray emissions. Is the same effect expected to occur for dark matter accretion into a supermassive black hole? ...
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80 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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65 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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40 views

Neutrinos born before inflation

What would happen, if there was (hypothetically, for any reason) a very large number of neutrinos+antineutrinos before the inflation period. They probably dont like to annihilate too much. I would ...
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89 views

Can the proportion of dark energy change?

This post generalizes the posts: - Proportion of dark matter/energy to other matters/energy at the beginning of the universe? - How do people calculate proportions of dark matter, dark energy and ...
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Dark matter detection

In the detection of weakly interacting massive particles (WIMPs), which is the basis of dark matter, what is the use of the tank filled with liquid xenon? I mean, how does the releasing of photons ...
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Ability to detect pulsars

Am I correct it remembering that unless a pulsars beams plane faces earth we can not detect them. And that similarly inbetween the pulses we can't see them either? If so how does this differ from ...
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190 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 ...
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180 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 ...
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231 views

Signs of supersymmetry and thus dark matter at CERN

The Large Hadron Collider at CERN has just re-started after a two year pause and is now running at unprecedented levels of 6.5 TeV, with collisions that will release up to 13.5 TeV. With this increase ...
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91 views

How is dark matter meant to explain the faster than expected rotation of galaxies? [duplicate]

The stars on the outer edges of galaxies go around faster than they should be. How is dark matter meant to account for this? if you just add more mass wont that just give it a greater gravitational ...
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Big Bang Question

In the early Universe it it's believed that matter and anti-matter annihilated one another till there was but a remaining 1% left. In a matter/anti-matter collision, is there not an explosion of ...
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Elastic vs Inelastic vs isospin violating scattering particle physics models

I'm looking for a nice paper that explains the difference between three particle physics models for spin-independent dark matter interaction with nuclei: elastic, inelastic and isospin violating ...
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97 views

Dark energy before radiation or after?

In the cosmic history of the universe, does the dark energy comes before the radiation epoch, or only now, in the 'matter' universe (matter dominated era)? Because, we now know that like 75% of our ...
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542 views

Has Bose-Einstein theory been considered for dark matter?

Has Bose-Einstein theory been considered for dark matter? The theory would explain why no measurable radiation is emitted due to zero temperature--its lack of interaction with other matter and its ...
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25 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 ...
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48 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 ...
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280 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 ...
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63 views

Bulge-Disk decomposition in galaxies

I'm starting a new project on dark matter astrophysics in which I have to extract from some data (I will write some below) the surface brightness, to later construct the mass density profiles of de ...
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60 views

What $f(R)$ models pass most of the known constraints? [closed]

In most papers and talks about $f(R)$ gravity authors repeatedly state that the model proposed by Starobinsky 2007 $$ f(R)=R+\lambda\,R_{0} \bigg[\bigg(1+\frac{R^{2}}{R_{0}^{2}}\bigg)^{-n}-1\bigg] $$...