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Questions about the source or effects of the matter that makes up 85% of the matter in the universe but appears to only interact gravitationally.

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133 views

Why aren't neutron stars full of dark matter?

Dark matter interacts with the gravitational force right? Well, unlike black holes, neutron stars are actually visible, and they're an enormous gravitational sink, so dark matter should collect to ...
1
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2answers
56 views

Dark Matter Curvature

Does Dark Matter affect Space Time Curvature? If so, then what is the formula to calculate space time curvature due to dark matter?
6
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2answers
146 views

How does the amount of dark matter in measured galaxies vary?

I have recently viewed two news articles announcing a galaxy composed almost entirely of dark matter and one with hardly any. This made me wonder if there is a "continuum" of percentages of dark ...
5
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2answers
192 views

Galaxy discovered lacking Dark Matter

Recently a Galaxy was discovered that contained no Dark Matter. I was wondering what explanation could be offered for this ? This Galaxy also contains only 1% as many Stars as our Milky Way does . Is ...
9
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0answers
271 views

Is it “weird” that all disc galaxies rotate once every billion years?

In a recent paper (Cosmic clocks: A Tight Radius - Velocity Relationship for HI-Selected Galaxies by Meurer, et al.), it was noted in the conclusion that: [This] implies a constant orbital time of ∼...
2
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2answers
94 views

Dark matter virtual objects hypothesis [closed]

I've hypothesized for many years in my head that dark matter are the gravitational after effects of objects that have exploded. My understanding of physics is that when an object explodes, its center ...
5
votes
3answers
256 views

How is dark matter different from ordinary (visible) matter?

How is dark matter different from ordinary (visible) matter? 1) Does dark matter consists of invisible astronomical objects like white dwarfs, black holes? 2) Has dark matter not been directly ...
2
votes
2answers
178 views

Dark matter emitting EM radiations beyond our currently known spectrum?

Could it be possible that dark matter is emitting EM radiations on a scale that is not known or perceivable by humans yet and undetectable by man-made instruments? A type of radiation that our ...
2
votes
2answers
138 views

Circular velocity in axisymmetrici potential [duplicate]

If a matter distribution is spherically symmetric, the circular velocity is straightforwardly related to the mass via: $v_{circ} = \sqrt{GM/r}$ In an axisymmetric potential, on the other hand hand, ...
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1answer
127 views

The consequences and the mechanisms of a shift of the Earth away from the sun

First premise: I have already made this question in the worldbuilding section, but since it is a very specific question many have recommended me to write in the astronomy section so here we are. ...
0
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1answer
51 views

How does dark SMBH evaporate?

I read that Dragonfly44 is a galaxy mostly consists of dark matter, and it should contain a super massive black hole too. If there really is a dark SMBH, how does it lose mass? I think there is no way ...
0
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1answer
95 views

What are evidences of stationarity of rotation of galaxies

Recently I have found the article Does There Really Exist the Problem of the Dark Matter in Spiral Galaxies? which states that dark matter does not exist because astronomers are wrong assuming ...
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0answers
97 views

Could gravitational waves be the mysterious dark energy?

Since there are a lot of stellar black holes estimate to be around 100 millions alone in our milky way galaxy, maybe this facts might help explain the missing dark matter and I'll go even further... ...
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3answers
291 views

Why “Dark matter” is still considered? [closed]

Why the 'dark matter' is still the main research trend? It looks like a waste of time, money and resources. https://www.youtube.com/watch?v=MvNCWMD6so4
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0answers
90 views

Will galactic filament indefinitely expand while its galaxy clusters indefinitely disperse?

Exciting discoveries of weak gravitational lensing suggest the existence of galactic filaments made of dark matter that are the size of galactic superclusters. My questions involves the future of the ...
1
vote
1answer
314 views

Relationship between Dark Energy and Dark Matter

I have encountered two seemingly contradictory theories on this(I don't know which one of them is correct, or where I am wrong):- From Wikipedia: Measurements of cosmic microwave background (CMB) ...
3
votes
1answer
68 views

1-parameter NFW dark matter profile

This should be a straightforward exercise, but I'm struggling. Help is much appreciated I would like to parameterize a Navarro-Frenk-White profile with one parameter, using the correlation between ...
0
votes
1answer
190 views

rotation curve in the innermost part of galaxies

I read in Sofue's articles (1999) that he used a method to investigate the bulge of galaxies to obtain rotation curve of this part of galaxies. So my question is how could Vera Rubin et al. obtained ...
1
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0answers
88 views

Need help on Springel model for galaxy simulation

I am working on a code for galactic dynamics simulation. Initial conditions (positions and velocities) are based on a model with a massive dark halo and a thin exponential disk. Now, from the ...
9
votes
2answers
764 views

Is Anti-Dark Matter a thing?

Could there be such thing as anti-dark matter? If there is anti regular matter, why not anti-dark matter? If there is no such thing as anti-dark matter, why?
11
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2answers
213 views

Are black holes expected to contain the same ratio of dark matter to regular matter as the rest of the universe?

Are black holes expected to contain the same ratio of dark matter to regular matter as the rest of the universe? I've heard that dark matter is distributed in halos around galaxies. Does that make it ...
-4
votes
2answers
205 views

Are they talking about the observable universe or the unobservable universe? [closed]

When people say that 95% of the universe is dark matter and dark energy, are they talking about it being in the observable universe or the unobservable universe? Because surely all matter in the ...
3
votes
2answers
145 views

Is Dark Matter moving?

It sounds like dark matter makes up one quarter of the universe's mass-energy. And it's density is fairly uniform. But could it be simultaneously both uniform and moving - like currents in a lake. ...
29
votes
1answer
4k views

If dark matter bends light, how do we know the stuff in the sky is where we think it is?

We measure movement, position, and many other things of an object in space because of its light and what we can measure with it. But as far as I know there's supposed to be a HUGE amount of dark ...
4
votes
1answer
146 views

Who found the existence of Dark Matter?

Dark Matter's observational evidence is widely attributed to Vera Rubin based on her observation of galaxy rotation curves with Kent Ford in 1970s, which was later confirmed by Albert Bosma in 1978. ...
2
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1answer
78 views

Is it true dark matter was discovered whilst looking at the rotational speed of galaxies?

Just a little something whilst a dark matter pioneer moves onto a better place. This commentator writes: My understanding is that dark matter was "discovered" when trying to find out why stars in ...
6
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2answers
138 views

Is normal matter always accompanied by dark matter and vice versa?

Is normal matter always accompanied by dark matter and dark matter by normal matter? Was ever observed effect of gravity lensing without normal matter?
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1answer
250 views

In what ways does the mass and energy of the milky way curve space time?

Space is curved by mass (or more precisely by mass and momentum as described by the stress-energy tensor). The milky way system has a lot of mass and a lot of energy. In what ways is space-time curved ...
0
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1answer
491 views

Can virtual particles be the source of dark matter and dark energy? [closed]

I had this question for a long time. But otherwise the question basically sums the whole thing up.
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3answers
83 views

Could space time curve from the vantage point of earth and out into the universe, and would d = 1 / P in that case give false estimates?

The seventeenth century saw a revolution in astronomy. The invention of the telescope and the acknowledgement of the heliocentric system triggered a race amongst astronomers to measure the parallax of ...
3
votes
1answer
406 views

Latest cosmological parameters

I'm looking for the latest values (with uncertainties) of the four main cosmological density parameters $\Omega_i$ : \begin{align}\tag{1} \Omega_{\text{mat}} &={} ?, &\Omega_{\text{rad}} &=...
4
votes
1answer
204 views

Could undiscovered smaller black holes within galaxies be an explanation for dark matter?

From what I've read, given the speed of stars rotating within a galaxy and the known mass, the stars' speed is too fast to stay in orbit. Dark matter was proposed to explain this but is it possible ...
1
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0answers
66 views

What's the density of dark matter (clouds)?

How much mass per unit volume do known dark matter have, for instance in the Bullet Cluster? Does the density vary in space, for example, do individual dark matter structures have denser cores?
20
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1answer
3k views

Does the recent news of “ten times more galaxies” imply that there is correspondingly less dark matter?

Nature: Universe has ten times more galaxies than researchers thought NASA feature: Hubble Reveals Observable Universe Contains 10 Times More Galaxies Than Previously Thought Headlines sometimes ...
0
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2answers
84 views

Is there evidence for the speed of gravity? [duplicate]

Is it an assumption that the speed of propagation of gravitational waves is exactly the same as the speed of light? If the speed of gravity is only slightly less than the speed of light, the effect ...
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0answers
44 views

NFW Profile for Seyfert Galaxies

I would need to know the NFW (or similar) profiles of several galaxies/clusters to estimate the line of sight Dark Matter column densities. I have found them in a couple of cases, but not for many ...
0
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1answer
116 views

Could dark matter be “inside-out” reality?

Where we are, and in the conventional galaxies etc. that we see, there is a whole lot of relatively uniform space but in isolated places within that space, there are pockets of concentrated "mass" ...
3
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2answers
128 views

Is time taken into account by astronomers when creating and using maps of the universe?

There's really two questions I'm asking. Firstly, when maps are produced of stars and galaxies, are they just produced as we see them now from our viewpoint? Or are they based on the motion of those ...
13
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2answers
375 views

Conventional matter to dark matter ratio, outside of galaxies (Bounty!)

I'm pleased to offer a bounty to attract more attention to the fantastic Astronomy site. Consider say this outstanding diagram from another question, To begin with galaxies have a typical density D. ...
1
vote
1answer
366 views

What is 'Dark Fluid'?

Is this term official jargon/wording for 'Dark Matter'? If so, why include the word "Fluid" if there is supposedly no viscosity in actual space. It would be like saying 'Hey, want to go swim in my '...
0
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2answers
70 views

Warm and Hot dark matter density profiles

For cold dark matter, density profiles are well known and easy to find information about - eg. NFW, Burkert, Einasto, and others. But for some reason I couldn't find explicit expressions for the ...
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0answers
60 views

Does a self-gravitating gas necessarily develop turbulence?

Though we may still doubt the exact driving mechanism of turbulence in each particular case (ISM, MC, circum-BH/-stellar discs, atmospheres...), can I say that in a sphere of dark matter particles no ...
12
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1answer
1k views

Can dark matter be found in the shape of planets, galaxies etc.?

If dark matter has gravity just like normal matter, does that mean it can also form planets, solar systems and so on? Any answer will be appreciated.
2
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1answer
80 views

Dark matter inertial mass

We know the existence of dark matter because we can test its gravitational mass (e.g. in gravitational lens) but, since we cannot see this matter, how we can be sure that it has an inertial mass, and ...
1
vote
1answer
117 views

Initially non-flat space-time makes dark matter obsolete$\dots$

After the Big Bang, dark matter clusters and build the seeds for visible matter, that then forms stars, planet, you, me, everybody... But do we really need dark matter to build cluster first. What if ...
0
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1answer
151 views

How does dark matter interact with black holes?

Is dark matter trapped near / in black holes, like regular matter is, or does something different happen with dark matter?
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1answer
87 views

Could dark matter assist with star formation?

This is related to the question: "Can dark matter decrease the Jeans length?" If dark matter assists in any way with star formation, shouldn't it be detectable by precisely measuring velocities in ...
4
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1answer
133 views

Is dark matter influenced by gravity of baryonic matter?

As far as I know galaxies and clusters form along so-called "galactic filaments" which are influenced by a dark matter web that organises them in to this position in the universe. So it looks like ...
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3answers
203 views

Can “dark matter” be the additional mass from the speed of the Galactic Cluster?

Considering that the Earth orbits the Sun at 100 000 km/h and that the Sun orbits the Milky Way at almost 1 000 000 km/h, could it be possible that the galactic cluster orbits some super cluster at ...
1
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2answers
100 views

Is Higgs Boson mass equal to the missing mass of dark matter?

Sorry if this is a very lay question. I am just an armchair physicist. The Higgs Boson was just recently discovered, and it has a mass which is considerably larger than a proton. If this Higgs Boson ...