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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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Two species of dark matter?

At this point in time, evidence for the existence of dark matter has accumulated in many ways: it affects galactic rotation curves plays a major role in cosmology, and the evolution of structure in ...
Alexey Bobrick'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
24 votes
5 answers
5k views

Is it possible that all dark matter is made of rogue planets (free-floating planet)?

Is it possible that all dark matter is made of rogue planets (free-floating planet)? (and other stuff like asteroids or meteoroids)
Clausia's user avatar
  • 785
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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22 votes
1 answer
2k views

Explaining Dark Matter and Dark Energy to layman

With my little knowledge, I know this: Dark Matter The center of a galaxy controls/attracts its objects (stars, planets, comets etc.) towards itself because of gravity. But the mass of the center of ...
Farhan's user avatar
  • 701
21 votes
1 answer
3k views

Why doesn't dark matter clump strongly in the center of galaxies, since it doesn't feel either radiation pressure or the Pauli exclusion effect?

Dark matter is described as being spread not only throughout a galaxy, but also around it in a halo of some sort that extends far beyond the visible parts of the galaxy... In fact, dark matter haloes ...
Kurt Hikes's user avatar
  • 5,177
21 votes
1 answer
493 views

Dark Matter Particle Candidates

Dark matter appears to dominate the matter component of the universe as compared to luminous, or baryonic, matter. Though it does not interact electromagnetically (it doesn't absorb, scatter, or emit ...
astromax's user avatar
  • 5,953
20 votes
7 answers
4k views

Could light be dark matter?

Is it possible that light itself is dark matter? I am speaking of photons (e.g. visible light, infrared, ultraviolet, etc...). I realize light is understood to be massless, but it is obvious it at ...
Jonathan's user avatar
  • 4,381
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
20 votes
1 answer
757 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 ∼...
called2voyage's user avatar
  • 6,300
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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18 votes
3 answers
6k views

What is the estimated density of the dark matter?

What is the estimated density of the dark matter? Some clumps of dark matter might have higher density and others might have lower density. So what is the estimated density range of dark matter? Is it ...
Joe Jobs's user avatar
  • 537
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
18 votes
1 answer
989 views

Are there any alternative explanations for the gravitational force we attribute to dark matter?

It always seemed counter-intuitive to me that we observed an measured a gravitational force and since the universe has not enough mass to account for it, the conclusion was to say there's a different ...
Eduardo Serra's user avatar
17 votes
3 answers
326 views

On (minuscule) dark matter production in supernovae

It is believed that dark matter is made of particles, which interact with matter only weakly and gravitationally. One common candidate for dark matter are so called WIMPs. WIMPs, specifically, are ...
Alexey Bobrick's user avatar
16 votes
9 answers
11k views

Why is it ok for people to be saying that dark matter makes up x amount of the universe when we don't know what it is?

It strikes me as contradictory that the scientific community will say that we don't know what dark matter is, but be happy to state things like "dark matter makes up about 85% of the cosmos" ...
Zinn's user avatar
  • 405
16 votes
3 answers
2k views

How do we know dark matter/dark energy exists?

I've never quite understood the theory behind why dark matter and dark energy exist. I know it has something to do with gravitational pull being stronger than what we calculate it SHOULD be, could ...
Rich's user avatar
  • 609
16 votes
1 answer
3k views

How are we observing the newly discovered "dark galaxy" J0613+52, if it has no stars and is so far away from other galaxies?

I just came across a New York Times article talking about a newly found Low Surface Brightness (LSB) galaxy (also called “ultra-diffuse galaxies” or “dark galaxies”). The new galaxy, J0613+52, was ...
Curious Layman's user avatar
15 votes
3 answers
5k views

Can there be planets, stars and galaxies made of dark matter or antimatter?

We know that the universe has more dark and anti matter as compared to normal matter. Can there be dark matter galaxies or antimatter galaxies?
Dark Knight's user avatar
15 votes
3 answers
3k views

Is there more dark matter than we previously thought?

With the recent Nature publication showing that M dwarfs did not form in prior epochs as frequently as we had thought, what implications does this have on galaxy mass estimates and, by extension, the ...
Justin T's user avatar
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14 votes
1 answer
263 views

How will the recent appearance of a supernova, the closest in 27 years, help reduce the uncertainties in our measurements of dark energy?

A supernova has been recently spotted on M82, also known as the cigar galaxy. Being the closest to earth in 27 years and given the advances of technology this article proposes that: ...as the ...
Eduardo Serra's user avatar
13 votes
1 answer
2k views

How would "dark matter", subject only to gravity, behave?

If we were to hypothesise that the Universe contained a significant mass of "dark matter" particles subject only to gravity, presumably general relativity would give us a good idea of how ...
mikado's user avatar
  • 233
13 votes
2 answers
3k views

Is Dark Matter possible if there is dynamical friction?

If dark matter existed: wouldn't it slow down the orbital velocity of stars in galactic disks by dynamical friction more than it would accelerate them through additional mass? The original orbital ...
Reggie Grünenberg's user avatar
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
13 votes
2 answers
401 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 ...
joseph.hainline's user avatar
12 votes
2 answers
367 views

What's the smallest scale at which dark matter has been measured?

What is the smallest scale at which we have detected "dark matter" (more kinetic energy than would be predicted)? If you don't mind indulging a follow-up: Would its detection on smaller scales be ...
Steve Clay's user avatar
12 votes
5 answers
6k views

What mechanism causes oscillations of the solar system's orbit about the galactic plane?

In a recent paper (news release here) Lisa Randall and Matthew Reece propose that a dark matter disk coinciding with the galactic plane together with the solar system's oscillations through the ...
Chris Mueller's user avatar
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
10 votes
1 answer
2k views

Is the amount of dark matter the same as you look back through time (further away from earth)?

In the hope that it may provide information on the development/evolution (if any) of dark matter over time, are there any differences (eg. in structure or concentration) in the dark matter at large ...
Zinn's user avatar
  • 405
10 votes
2 answers
1k views

Could we detect dark matter by black holes gaining unexplained mass?

Dark matter is said to interact only gravitationally, so it won't commonly form black holes by itself. But if a black hole is already there, and dark matter encounters the event horizon, it should go ...
Hene's user avatar
  • 255
10 votes
2 answers
2k 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?
user16049's user avatar
  • 101
10 votes
1 answer
660 views

Are black holes considered part of baryonic content of universe?

Are black holes (like those detected by LIGO, for instance) part of baryonic content of universe or part of dark matter? Why?
Leos Ondra's user avatar
  • 1,074
9 votes
1 answer
2k views

Could dark matter be wrong? [duplicate]

As I understand, the evidence for dark matter is the observation of the gravitational dynamics of objects around the size of galaxies and above. They move in a way such that the equations imply there ...
mbsq's user avatar
  • 193
9 votes
1 answer
2k views

How can dark matter be observed?

Look at this picture: It looks as if dark matter is observed. But what is actually observed? doesn't this picture prove MOND and emergent gravity (both assuming a different gravity tied to normal, ...
Deschele Schilder'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
9 votes
2 answers
363 views

Has someone looked the other way?

I learned that gravity always pulls, it is always attractive. There is no antigravity, no "negative" mass. I also learned that most matter is dark, invisible. We know that because we see visible ...
Jens's user avatar
  • 203
8 votes
4 answers
1k 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 ...
Vane Voe's user avatar
  • 191
8 votes
1 answer
298 views

Have we discovered a Galaxy lacking in Dark matter?

This question is relevant but it was speaking about a specific discovery reported by pieter van Dokkum, and the answer then mentioned it was disputed whether the paper's conclusion is even correct. I ...
Hisham's user avatar
  • 231
8 votes
1 answer
1k views

Can dark matter accumulate at Lagrange points?

Interplanetary dust can accumulate at Lagrange points . "Kordylewski cloud - Wikipedia" https://en.m.wikipedia.org/wiki/Kordylewski_cloud But can dark matter accumulate at Lagrange points ...
user avatar
8 votes
2 answers
154 views

Do the orbits of satellite galaxies show the influence of dark matter?

I understand how galaxy rotation curves show the influence of dark matter, or something else that would produce similar behaviour, such as Modified Newtonian Dynamics (MOND). Do the orbits of ...
John Dallman's user avatar
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
7 votes
1 answer
435 views

Scientific evidence against CMB originating from “Oort Soup”?

In this article (and references therein) the author claims that the Cosmic Background Radiation can be explained as black-body radiation originating from the cold bodies filling the interstellar space ...
Prof. Legolasov's user avatar
7 votes
1 answer
344 views

Do the Bullet Cluster remnants prove that dark matter consists out of particles?

Some time ago the remnants of a collision between two collections of stars were discovered. These remnants are called the Bullet Cluster: The color blue (non-visible in reality) represents the ...
Deschele Schilder's user avatar
7 votes
2 answers
420 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 ...
Peter U's user avatar
  • 1,619
7 votes
1 answer
236 views

Could dark matter form coherent bodies the size of stars or planets?

Is it possible that dark matter could collapse gravitationally, forming massive bodies similar to stars or planets? When I say "similar", I don't mean to imply that they would undergo ...
Keith Thompson's user avatar
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
7 votes
2 answers
311 views

Can dark matter be normal matter after all? [duplicate]

MACHO's and RAMBO's are both baryonic (and leptonic) forms of matter that can't be observed by their nature. They barely emit or reflect light. Black holes, neutron stars, or brown dwarfs (or groups ...
Deschele Schilder's user avatar
7 votes
2 answers
812 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 ...
Jack R. Woods's user avatar
7 votes
1 answer
151 views

Density of hydrogen between galaxies

From watching a video on youtube, it states that Dark Matter is 6 times more abundant than known matter. I was wondering if it was possible to have hydrogen clouds between the universes galaxies. The ...
LDC3's user avatar
  • 2,036
6 votes
3 answers
929 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 ...
Basak's user avatar
  • 85

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