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Questions tagged [dark-matter]

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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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 ...
user29434's user avatar
2 votes
2 answers
364 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. ...
scorpdaddy's user avatar
31 votes
1 answer
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 ...
Sebastian Araneda's user avatar
4 votes
1 answer
408 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. ...
Janus Boffin's user avatar
3 votes
1 answer
348 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 ...
hawkeye's user avatar
  • 469
6 votes
2 answers
194 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?
dllhell's user avatar
  • 273
2 votes
1 answer
774 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 ...
memex's user avatar
  • 101
0 votes
1 answer
2k 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.
GameCoder's user avatar
  • 103
1 vote
3 answers
121 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 ...
memex's user avatar
  • 101
4 votes
1 answer
1k 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}} &=...
Cham's user avatar
  • 273
5 votes
1 answer
278 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 ...
Andrew Park's user avatar
1 vote
0 answers
95 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?
LocalFluff's user avatar
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22 votes
1 answer
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 ...
uhoh's user avatar
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0 votes
2 answers
119 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 ...
Colin's user avatar
  • 79
0 votes
1 answer
204 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" ...
it's a hire car baby's user avatar
2 votes
2 answers
273 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 ...
nevster's user avatar
  • 121
19 votes
2 answers
843 views

Conventional matter to dark matter ratio, outside of galaxies

Consider say this outstanding diagram from another question, To begin with galaxies have a typical density D. Intergalactic space has a much lower density d. As we know: in galaxies (with density D) ...
Fattie's user avatar
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1 vote
1 answer
447 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 '...
NormLDude's user avatar
  • 111
0 votes
2 answers
150 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 ...
TensoR's user avatar
  • 25
13 votes
1 answer
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.
Vase Dodevski's user avatar
2 votes
1 answer
233 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 ...
Emilio Novati's user avatar
1 vote
1 answer
152 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 ...
draks ...'s user avatar
  • 385
1 vote
1 answer
263 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?
Jonathan's user avatar
  • 4,381
2 votes
1 answer
143 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 ...
Jack R. Woods's user avatar
3 votes
1 answer
334 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 ...
Marijn 's user avatar
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-1 votes
3 answers
382 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 ...
Dagelf's user avatar
  • 99
1 vote
2 answers
147 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 ...
Oliver Watkins's user avatar
2 votes
0 answers
59 views

Does the quantity of dark matter needed in the Milky Way to give the stars their speed compare with the speed of the Milky Way?

Dark matter was needed to give the stars in a spiral galaxy a cause of their speed. So they proposed there must be some extra dark matter in the Galaxy. The total extra mass of dark mater is quite ...
Marijn 's user avatar
  • 1,826
8 votes
2 answers
307 views

Can dark matter decrease the Jeans length?

I am wondering if there are any models of interstellar cloud collapse out there which take dark matter into account. If dark matter has local perturbations or density fluctuations, then that may be ...
dualredlaugh's user avatar
1 vote
1 answer
169 views

What's the relation between Einstein's Gravitational Theory and Dark Matter?

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 ...
Arbër Ll's user avatar
4 votes
1 answer
106 views

Can an SMBH recycle dark matter into energy?

I just had a conceptual question, hopefully it makes for some really interesting answers. I was wondering, as most galaxies have an SMBH at their centre (see Kormandy & Richstone 1995; Richstone ...
MichaelJRoberts's user avatar
4 votes
1 answer
218 views

Does Dark Matter affect the motion of the Solar System?

Would dark matter have a similar effect on the Solar System as it does on the Milky Way? I'd imagine it could help hold together some of the Solar System bodies or at least affect their motion, right? ...
Sir Cumference's user avatar
0 votes
1 answer
397 views

TIME TRAVEL-Can it be really done? [closed]

Is it posssible for us to time travel? Is light essential factor or the dark matter and dark energy?
Sanjeev K.C.'s user avatar
20 votes
3 answers
1k views

Could there be dark matter black holes?

Could dark matter compress and form black holes? Since dark matter is even more abundant than normal matter, a dark matter black hole should not be rare...right?
Sir Cumference's user avatar
18 votes
2 answers
70k views

What are the differences between matter, dark matter and antimatter?

I thought dark and anti matter were kinda the same, but after saw a video, they mention that dark matter is not antimatter but their explanation is a little fast so I got doubts. What are the ...
Alex Sifuentes's user avatar
2 votes
1 answer
199 views

Dark Matter Detection

A paper appeared at the arXiv.org (in April or May) claimed that the writers have found the gamma rays emitted by annihilation of dark matter in a satellite galaxy of the Milky Way by examining the ...
Sony's user avatar
  • 131
3 votes
1 answer
157 views

How close are we to be able to detect and measure gravitational lensing inside the milky way?

Gravitational lensing takes advantage of statistically uniform distributions of background objects in order to infer a credible map of dark matter concentrations that isn't too noisy. If there are too ...
lurscher's user avatar
  • 153
7 votes
1 answer
853 views

Is there Dark Matter inside the Earth?

Since Dark Matter is assumed to interact gravitationally, it follows that the gravitation of massive regular matter bodies should have an effect on it. Even if it is otherwise weakly interacting with ...
Serban Tanasa's user avatar
1 vote
2 answers
287 views

Is it certain that dark matter consists of particles? (And not just curved space)

The main idea about dark matter today seems to be supersymmetry. That there exists a set of yet undiscovered fundamental particles which (in a mathematically most convenient way) mirror the particles ...
LocalFluff's user avatar
  • 11.4k
11 votes
2 answers
4k views

Why aren't brown dwarfs the dark matter?

There seems to be not enough matter to account for the fact that the speed of some stars located far from the Galaxy center is almost the same speed as those stars found nearer to the center of the ...
user6760's user avatar
  • 2,501
2 votes
1 answer
472 views

Mass resolution

Can someone define mass resolution in terms of cosmological simulations such as the millennium simulation? Is it just the smallest mass that a dark matter particle can have and still be detected by ...
user's user avatar
  • 21
1 vote
1 answer
709 views

Shadows of Light = Space or Dark Matter?

Perhaps my title is misleading. but here is my understanding and I'm looking for confirmation. You cannot have dark without light. The only thing faster than light is darkness (i.e. shadows) Stars ...
Hituptony's user avatar
  • 121
4 votes
2 answers
233 views

Is there a connection between black holes and dark matter/energy?

Is there a spatial or gravitational relationship between black holes and dark matter/energy?
Vincent Ashley's user avatar
-5 votes
2 answers
617 views

Does "Dark Matter" really exist?

Does dark matter really exist or is just a made-up theory in order to cover up the loopholes in the Big Bang theory, and also to explain why universe is expanding at an accelerated rate?
sushil kumar's user avatar
5 votes
2 answers
1k views

What's the mass of the interstellar neighborhood of the Sun?

What's approximatively the mass of the interstellar neighborhood of the Sun ? (for example the neighborhood of radius 50 light-years). Remark: The mass of the observable matter should be completed ...
Sebastien Palcoux's user avatar
4 votes
2 answers
697 views

Galaxy rotation curve and dark matter

I am reading "The Essential Cosmic Perspective" by Jeffrey O. Bennett, Megan O. Donahue, Nicholas Schneider, Mark Voit. In Chapter 14, it is stated that an evidence of the presence of dark matter in ...
velut luna's user avatar
9 votes
1 answer
753 views

Is there a strong galactic magnetic field?

My main question is: Is there a strong galactic magnetic field, perhaps driven by the supermassive black hole at the center of our galaxy? I am also wondering if this field would be strong enough to ...
Jonathan's user avatar
  • 4,381
0 votes
1 answer
174 views

What are dark matter and dark energy? [closed]

I've recently read about dark matter and dark energy. But unfortunately, there were not enough answers for me. The article I read was more of a hypothesis than a real answer. So I'm asking for all the ...
user16901's user avatar
6 votes
2 answers
144 views

Deriving Dark Matter; specifically looking for a table of stellar speed versus distance from center of galaxy to derive dark matter

I'm trying to find some data that I can use to derive dark matter (in a loosey-goosey sort of way, I won't be too rigorous). I'm helping a friend out with a final project for his astronomy course and ...
Ben Kushigian's user avatar
1 vote
1 answer
648 views

Can the theory of multiverse explain dark matter?

If there are many universes, they must have a gravity effect on each other. Since dark matter is measured through gravity, but we don't know the mass behind it, isn't it possible that it comes from ...
ruedi's user avatar
  • 129