# Tag Info

1

Part of the LHC program is to find new particles that can be what dark matter is: very weakly interacting particles. This will show that an extension to the standard model would be correct. This will follow the pattern: "for every particle there exists an antiparticle", or a particle can be the antiparticle for itself, so yes, in this case there will be ...

1

Yes, the article you linked and quoted is describing a proposed explanation for observed diffuse gamma ray emissions from the center of our galaxy. The proposed mechanism is that of dark matter/anti-dark matter annihilation in the alleged dark-matter halo in our galaxy. However, you seem to have gotten a wire crossed - this has nothing to do with Gamma Ray ...

2

Dark matter cannot be made out of quarks. Primordial nucleosynthesis is well understood, and the limits on how much matter it could have created are restricted by the relative amounts of hydronge, helium, etc that were created. For details see the question Why can't dark matter be baryonic? and Why isn't dark matter just matter?. You are quite ...

2

No-one knows what dark energy is, but we can be fairly sure it is not related in any way to the electromagnetic force for the simple reason that dark energy is uniformly distributed and charged matter is not. If the two were related we would expect some correlation between them. Incidentally, The Magnetic Universe is an excellent book about cosmological ...

3

Assuming dark matter is a WIMP, NASA made a computer simulation on dark matter particle annihilation to see what would happen when dark matter fell into a black hole. According to the article, it may produce gamma ray as the collisions of dark matter particles increase closer to the black hole. Here is the preprint for the NASA simulation: ...

-5

Dark mass, not dark matter. The mass which fills 'empty' space is beginning to be referred to as the 'dark mass' in order to distinguish it from the baggage associated with dark matter. 'Dark Energy/Dark Mass: The Slient Truth' https://tienzengong.wordpress.com/2015/04/22/dark-energydark-mass-the-silent-truth/ "That is, all that we are certain about [is] ...

4

As I understand your question, and after watching your simulation, it seems that you actually only have dark matter (DM) in your simulation. An N-body code simulates DM, i.e. particles that interact only by gravitation. If you want to take it a step further, you want to include gas, i.e. particles that interact both by gravitation and by hydrodynamics. This ...

1

I've written a few small gravity simulations, and I would bet that the problem is that the particles aren't colliding. I know this doesn't answer your original question, but I think that's the answer to fixing your simulation.

1

Dark matter has a small/negligible influence in the Solar System because there isn't all that much of it in the Solar System, compared to say the mass of the Sun. The NFW profile is the current default density profile for DM "haloes" (spherical-ish self-gravitating structures, such as the one in which the Milky Way resides). This is a fit to the density as ...

4

The answer of Acid Jazz is correct in every point, in my opinion. However, I think that the problem in your simulations is not dark matter, but something more subtle. Perhaps I oversimplify here, but dark matter will behave in your model exactly like normal matter, with the exception of being dark, not visible. It is in fact exactly the case of the two ...

1

My best guess for these questions: (but I am no expert so it's a guess, right?) Should the dark matter be at all affected by the gravity of the visible particles? Yes Or should it be a one-way interaction? No, gravity should act equally on visible and dark matter. What makes the dark matter stay "in place" to preserve its "compressing" effect ...

0

I think in general there are a wide class of models that should pass cosmological and astrophysical constraints. The Living Review on this is a good place to look. In section 14 they explain the basic constraints on allowed types of $f(R)$ models. It seems like they amount to $f_{,R} > 0$ and $f_{,RR}>0$ when $R>R_0$, where $R_0$ is the scalar ...

2

People are usually more interested in the reverse process of production, that is the annihilation of dark matter particles. This is simply because it may be easier to see the products of annihilation (which might produce photons as a by-product) than to notice a small amount of ordinary matter that has "disappeared" to produce dark matter. And finding ...

0

Is Dark Matter expected to be equally distributed in our solar system? Not by relativists. Note Einstein saying this in The Foundation of the General Theory of Relativity: "the energy of the gravitational field shall act gravitatively in the same way as any other kind of energy". Gravitational field energy aka spatial or vacuum energy is dark. And it ...

8

Short answer: To first order the density of dark matter in the solar system should be uniform. To second order, no, it is not. Gravitational focusing will alter the density depending where in the solar system you are. Longer answer: The dark matter density is expected to be roughly uniform on the scale of the solar system, and to be around $10^{-22}$ ...

17

Dark matter is pretty uniformly distributed on Solar System scales. Yes, massive objects would attract it more. However, because it essentially does not interact with matter except through gravity, it will pass through stars and planets without stopping. Note that unless there is a collision to transfer energy, an unbound particle cannot become bound to a ...

1

On a cosmic scale, dark matter is not evenly distributed throughout the universe. It tends to attract normal matter toward it, so its distribution can be traced by observing the positions of galaxies and comparing their actual location with numerical simulations. Here is a photo showing how galaxies are found attracted along strands of dark matter: ...

1

Dark matter isn't equally distributed in places: it mostly lies within areas where galaxies exist. In a sense dark and light matter likes to clump together. Plus, it gathers in around together from it's own gravitational pull. I also think it would be rather impossible for dark matter within our solar system to be uniformly distributed, partly because dark ...

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