Linked Questions

18
votes
1answer
642 views

Distribution of Dark Matter around galaxies [duplicate]

It is well-known that measurements of the velocity profile in galaxies are not compatible with Newtonian laws. A way to circumvent the problem is to assume that galaxies are surrounded by a spherical ...
3
votes
1answer
137 views

Why does not dark matter gather and form celestial bodies? [duplicate]

since the only thing we know about dark matter that it "attracts" and affect our Baryonic matter's momentum and speed, which means that it does have mass of a sort. so why didn't we witness a ...
1
vote
1answer
432 views

Gravitational collapse of dark matter [duplicate]

The gravitational lensing evidence suggests the existence of massive and relatively dense regions of dark matter. However, if dark matter interacts only gravitationally, what would stop it from ...
1
vote
1answer
291 views

Why doesn't dark matter collapse into a black hole? [duplicate]

Dark matter supposed to be affected only by gravity and no other force. At the same time, however, dark matter forms halos around galaxies, that become visible examining how galaxies and clusters bend ...
0
votes
1answer
212 views

Why does dark matter form a halo, Unlike normal matter? [duplicate]

Hi I am curious to know why dark matter forms a halo? Or why doesn't normal matter form a halo.What is the difference between the two My level is amateur
0
votes
1answer
39 views

Does dark matter act gravitationaly to itself. If Yes, why does not form more compact objects? [duplicate]

Does dark matter act gravitationaly to itself.If Yes, why does not form more compact objects? Can this be explained as its components have enough kinetic energy to overcome the collapse?
32
votes
3answers
105k views

How is light affected by gravity?

Light is clearly affected by gravity, just think about a black hole, but light supposedly has no mass and gravity only affects objects with mass. On the other hand, if light does have mass then doesn'...
13
votes
3answers
3k views

If dark matter can't lose kinetic energy, then why is it not traveling at relativistic speeds?

I have read this question: The only way you can do this is to remove kinetic energy from the system. With normal matter this is done through electromagnetic interactions, which turn the kinetic ...
37
votes
1answer
2k views

How can dark matter collapse without collisions or radiation?

I understand that dark matter does not collapse into dense objects like stars apparently because it is non-interacting or radiating and thus cannot lose energy as it collapses. However why then does ...
8
votes
1answer
529 views

Why doesn't the dark matter halo co-rotate with the luminous disk? What keeps it from falling into the center if not angular momentum?

Why doesn't the dark matter halo co-rotate with the luminous disk? What keeps it from falling into the center if not angular momentum?
4
votes
1answer
242 views

How does Dark Matter form a halo?

Here are the velocity components of the Milky Way (according to Sofue et al. 2013) out to 20 kpc. The vertical axis is $k$ $s^{-1}$. The horizontal axis is $kpc$. The purple line is the rotation ...
2
votes
2answers
133 views

If dark matter can't interact electromagnetically, then how can it annihilate into photons?

I have read this question: 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, ...
3
votes
1answer
186 views

If dark matter can't clump together, then where was it when the observable universe was much smaller at the beginning of the universe?

I have read this question: To zeroth order, dark matter can only 'clump' as much as its initial energy (obtained soon after the big-bang) allows. One example of such a 'clump' is a 'Dark Matter Halo' ...
1
vote
4answers
114 views

Why can't dark matter lose energy by gravitational waves and collapse into itself?

Because of lack of electromagnetic induction, dark matter can't lose its gravitational potential energy. That is preventing it from collapsing like an ordinary matter cloud in space. But why can't ...
1
vote
1answer
99 views

Is the dark matter present only around the galaxies?

Dark matter is believed to give galaxies its shape and prevent them from flying apart. Is dark matter present only on outer edges of the galaxy or is it present throughout the galaxy?