Dark matter Definition and 935 Threads

Hi Guys, Can anyone provide links, books which explain the mathematical background of the field theory that explains the current accepted ^CDM model of the universe? Thanks Adarsh

If dark matter affects normal matter (by gravity), does that mean that normal matter also affects dark matter? I think it does... In which case; Black holes could attract BOTH dark and normal matter? Does this give any opportunity to "information loss"? What if some information in normal...

Why isn't the dark matter just randomly distributed? How does it know where to go? Why does the amount of dark matter increase the further away from the galaxy's center?

I've been working with NFW Dark Matter Halos recently. This is a particular density model for the halo developed by Navarro, Frenk, & White (NFW). The density structure has the form \rho (r) = \frac{\delta_c \rho_c}{(r/r_s)(1+r/r_s)^2} where \delta_c = \frac{200}{3}...

Hello fellows, Properly introducing myself into dark matter so in the quest for book suggestions from those of you who are into the topic. Thanks in advance

Most people come up with their own internal reasoning for things like this that have not been explained. I was curious on the community's various opinions and theories on this subject. I think it would be a fun exercise to help each other evolve our own theories on things like this. Standard...

Dark matter can't radiate heat (i.e. no electromagnetic energy). 1. Might it retain the original temperature at the moment of its creation? 2. If temperature is directly related to pressure and both are inversely related to volume, then would cosmic expansion mean that dark matter is as...

1. Gravity is the geometric curvature of space-time caused by massive objects. 2. Dark Matter surrounds galaxies. 3. Dark Matter is thought to be critical in galaxy formation. 4. The mass of Dark Matter creates curvatures in space-time around baryonic matter which forms galaxies. What roles...

Dark Matter constitutes 26.8% (wikipedia) of the observable universe. So where is it? I ask this question because although it is said to be not visible. It must interact with light matter at a gravitational level. It only makes sense to me that dark matter must be all around us and...

I'm not a physicist nevertheless I wonder about these things so here goes: On wikipedia I read that the universe contains: 68.3% Dark energy 26.8% Dark matter 4.9% Normal matter But I wonder why normal (light energy) is not mentioned here. Since the beginning of the universe a lot of light...

Is the amount of Dark Matter in a Galaxy equal the amount of Matter consumed by all the Black Holes in that Galaxy?

Can string theory explain dark matter and dark energy?

Hi, I am a research student in Theoretical Dark Matter Cosmology. I am currently working on the evolution of dark matter WIMP in the early universe. I am trying to understand how to derive the famous condition for dark matter decoupling,T = m/26. How do you get this condition from the...

Hey, guys. I'm writing a science fiction novel and would like to know if you guys think there's anything wrong with the grammar in this sentence: "Space-time tunnels required large amounts of dark matter to stay open, and they could not be closed during the course of the mission, for it took...

I have heard that perturbative quantum gravity calculation predicts an increase of constant G at large distances. So I simply wonder can this growth in G naturally explain the galaxy rotation velocity curve?

I need some smart people to explain to me why this idea I have, doesn't work. It's impossible for me to believe others have not thought it, since it's so obvious. What if spacetime is slipping backwards at the black hole at the center of every galaxy? So like a helicopter with no rotar...

For my research on astrophysics for the summer, a professor gave me this assignment but I don't know where to start. The question is: What methods could be used to find the dark matter distribution around a galaxy's central black hole?

I'm not a physics student (chemistry instead), and know extremely little about relativity, so this might be a dumb question and would appreciate simple answers. I'm just curious about this. :) So there is dark matter, which I understand to be the matter that is not detected but needed to...

UPDATE: New Paper discussion starts here: https://www.physicsforums.com/threads/erik-verlindes-new-view-on-dark-matter.755235/#post-5615947 This is all I could gather from abstracts of talks and colloquiums he gave this year. Each of them have a different bit of information ******************...

I'll be cautious in asking my my question because I'm out of familiar territory. But... Given the following: that dark matter interacts with baryonic matter (exclusively?) via gravity, that evidence for dark matter shows that it exists largely near baryonic matter, and we are (almost?)...

There is now evidence dark matter fills what would otherwise be considered to be empty space. 'Cosmologists at Penn Weigh Cosmic Filaments and Voids' http://www.upenn.edu/pennnews/news/cosmologists-penn-weigh-cosmic-filaments-and-voids "Dark matter ... permeate[s] all the way to the...

Hi. I've been looking into a possible career in physics once I graduate high school, and I was wondering which types of physicists study dark matter? I have heard astrophysicists do, but are there any others? Sorry if this question is in the wrong place, I've never posted anything before...

Ok, we have all read that space is expanding, especially in low mass areas between galaxies, as described by GR. And that mass bends space, like seen in gravitational lensing. My question is whether on larger scales and masses, like on the size of galaxies, space itself is warped? The properties...

I'm by no means a astrophysicists but I love reading, talking and studying all I can on the subject. I have a question on the original formation of dark matter. Could it be plausible that the formation of dark matter be the end result of the antimatter/matter collision right after the Big Bang...

How is dark matter distributed (as far as we know)? Let's stay with a single galaxy like the Milky Way. I heard that dark matter is even more concentrated in the center than in the halo, that it is falling off when moving outside, but since the halo is so huge (how huge, ten times larger?)...

Hello I have a question (well its 2 questions)... I'm not hugely knowledged on the subject so i tend to question things in a more ignorant way but i wanted to know two things: Firstly, how do astronomers weight a galaxy at an accurate level to be confident enough to say there is more stuff...

From other threads here I’ve gained a rough understanding of why Dark Matter forms into a halo around galaxies. It makes sense, since DM doesn’t interact and doesn’t clump together, that when a DM particle falls from the halo towards the gravitational centre of the galaxy it gradually...

I have been following stories about dark matter and have, I think, a layman's grasp of it, to whit: In 1933 the Swiss astrophysicist Fritz Zwicky, who studied clusters of galaxies while working at the California Institute of Technology, made an inference similar to one previously made by Carl...

Let me start off by stating that I have no formal education in Astrophysics, or any other education beyond high school, so if my question is stupid, just say so! Dark Energy, from my understanding Dark Energy is used to explain the expansion of the universe, because when we look at distant...

Primordial black holes as a dark matter candidate has been ruled out - http://www.nature.com/news/search-for-primordial-black-holes-called-off-1.14551

I have a Physic 201 understanding of physic. I understand that the most distant star (galaxy) that we can see from the Earth is 4.4 billion light years (the time of the big bang) away. I think this is called the viewing horizon. Assume a person on a planet 4.4 billion light years from...

Hello, I'm having trouble understanding why if there are dark matter particles and other such particles (neutrinos) streaming through the Earth at all times, why don't they just collide with the atoms in our body or the desk or what have you? I understand that they're probably "weakly...

Anyone knows about a good review of dark matter candidates? I want to learn about that but I would like to have a good review to start, any suggestion? Perhaps at an introductory level but if you have something advanced is more than welcomed. Books, papers, anything. Thanks

These papers, http://arxiv.org/abs/1402.4119 and http://arxiv.org/abs/1402.2301, make a case for direct detection of dark matter. The evidence takes the form of an unidentified emission line in the x ray spectrum of galactic clusters. The line is at a frequency and intensity consistent with...

I found an interesting paper... Dark Energy and Dark Matter as Inertial Effects A globally rotating model of the universe is postulated. It is shown that dark energy and dark matter are cosmic inertial effects resulting from such a cosmic rotation, corresponding to centrifugal and a...

What proof do we have that dark matter exists.

Simple logical observation dictates that our sun (for example) would gravitationally attract Dark Matter to the sun's center of gravity because DM is "gravitationally attractive". What is the value of the gravitational component of dark matter between the center of gravity of the sun and earth...

Since we can observe gravitational lensing and conclude that mass can affect the path of EM radiation it seems logical to me to assume that EM radiation will exert a slight gravitational attraction of it's own on a mass,- although I do not recall ever reading about this. Presumably the...

My Google searches are result in either something too complicated, or confusing non scientific journal articles. I always thought black holes were what people were referring to by dark matter. And I also was under the impression that small black holes should have all evaporated by now if they...

It could be useful to group some references for this: http://arxiv.org/pdf/1204.5379v1.pdf (Light Sterile Neutrinos: A White Paper) http://arxiv.org/abs/arXiv:1311.0282 (Sterile neutrino dark matter bounds from galaxies of the Local Group) I'd like some more references. Please share any good...

Homework Statement The andromeda galaxy has a velocity of 250 km/s as it rotates. The observed mass is 1 x 10^42 kg. If the galaxy is roughly a circle with a diameter of 66,00 light years how much mass is not accounted for visibly? Homework Equations Fc=mv^2/r and Fg=Gm1m2/r^2 The...

Homework Statement The andromeda galaxy has a velocity of 250 km/s as it rotates. The observed mass is 1 x 10^42 kg. If the galaxy is roughly a circle with a diameter of 66,00 light years how much mass is not accounted for visibly? Homework Equations Fc=mv^2/R Fg=Gm1m2/R^2 The...

I can undurstand that a dark matter halo is an area that surrounds galaxies and cluster of galaxies. dark matter haloes can be constructed using N-body simulations, but what is the relation between the haloes and the cluster which we observe. Running a simulation for a cosmology profile (...

What are the odds that there is a different event horizon for dark matter?

In other words, can dark matter be reconciled with GR without drastically changing the idea that force is due to space-time curvature? and in the case of the standard model is there any thoughts of how the force of dark matter is transmitted via the exchange of a particle? It seems that this...

Dark matter build up near or inside Black holes, thoughts ? I can see it making a real mess of the motions and energies of normal matter in and around a black hole or other very dense body that confines dark matter to a small adjacent region. Unslowed by frictional forces...think angry...

This paper, http://arxiv.org/abs/1311.1627, discusses the possibility of giant monopoles as a dark matter candidate. It is not a 'new' idea, it dates back to Dirac's giant monopole concept. In this case, the author suggests the 't Hooft-Polyakov monopole, which avoids the singularity problem of...

Sorry - a very vague question: Could a superconductor be used to detect dark matter? The dark matter might interact with electrons in the superconductor giving them some momentum. These moving electrons would constitute a supercurrent which could be measured - maybe! Perhaps the...

Homework Statement Suppose that a sprial galaxy has the mass profile: ##M_{disk}(r)=M_d[1-(1+\frac{r}{r_{rd}})e^{-\frac{r}{r_{rd}}}]## Where rrd=3Kpc. and Md is unknown. Like all galaxies, this galaxy also contains dark matter as well as its luminous matter. Using the rotational...

Hi all, I was wondering, could the dark matter just be the particles that actually pop in and out of existence inside the protons and neutrons and all other matter or anti-matter? Please enlighten me if my assumption is wrong somewhere.