Where is Dark Matter?

[GrandMasterK]

Is it supposed to be in empty space or is it in clumps everywhere including my room? Can anything be said about this stuff other then it generates gravity? For instance, how much could be clumped together into how small a space and would a light matter object be able to pass through it?

 

When I caught a few minutes of a show on TV they were talking about how dark matter is just kinda stitched into the universe. If that's so, then it should only move as the universe expands. Dark matter is supposed to be the reason the galaxies are being held together in the first place so shouldn't a galaxy's location be dictated on on the concentration of dark matter? If galaxies collide and get sucked into each other how do they escape the clumps of dark matter if dark matter isn't moving around in the universe (except for expansion..if even). Also, about black holes, does their presence disrupt the presence of dark matter in space?

[RyanJ]

The usual consensus (as far as I can gather) is that the dark matter exists throughout the universe in the form of weakly interacting massive particles (WIMPs) like neutrinos and so forth. As these are apparently generated by many phenomenon like the nuclear reactions within the heart of the sun but the actual composition of dark matter is unknown (as is the question of whether it really exists or not).

 

As for where they are apparently everywhere but it has bee speculated that the dark matter may clump at the centre of galaxies, in dwarf type starts and so forth.

 

Your question about galaxy locations seems to dictate that galaxies would prefer to be formed in some location rather than others and this seems wrong because all places in space are treated as equal. It could just be that as a galaxy started to form its gravity draws in the dark matter its self, in doing so it adds the extra mass that is required to hold the galaxy together.

 

Funnily enough dark matter doesn't seem to be the end of the story here, from what I've read 74% of the universe may be composed of something called dark energy, 22% as dark matter and the remains 4% as what we see.

[swansont]

The usual consensus (as far as I can gather) is that the dark matter exists throughout the universe in the form of weakly interacting massless particles (WIMPs) like neutrinos and so forth.

 

WIMP stands for weakly interacting massive particle, of which the neutrino is not one. WIMPS are one candidate for cold, non-baryonic dark matter. There are also "hot" non-baryonic possibilities, into which the neutrino falls, and baryonic possibilities.

 

I think it breaks down this way: if they move fast (i.e. hot) they have to have a small mass and if they have a large mass they have to move slowly (i.e cold), because large-mass, high kinetic energy non-baryonic matter would not explain the effects and/or we would have detected them already. Baryonic dark matter has to be cold, because it would be easy to detect if it were not.

 

http://en.wikipedia.org/wiki/Dark_matter

[Farsight]

Don't take dark matter (or dark energy) for granted. Check out Conformal Gravity:

 

http://xxx.lanl.gov/abs/astro-ph/0505266

[BenTheMan]

K---

 

One doesn't have to look too hard to find alternatives to Dark Matter and Dark Energy. Most of the alternatives (frankly) suck.

 

The best explanation for Dark Matter has to do with supersymmetry, which will probably be discovered at CERN within the decade.

 

As for where dark matter lives, it lives everywhere! There are dark matter particles streaming through you at this moment---they don't interract very strongly with matter (except gravitationally), so you of course won't notice anything.

 

As far as where dark matter lives, it has to live at the outsides of the galaxies---this is how it was first discovered. The normal models of spiral galaxies don't work at the very outer reaches of those galaxies. The models predict that many of the galaxies we see shouldn't exist. However, when one postulates dark matter living in the outer regions of the spiral arms, the models match the data exactly.

[JackMuChabas]

IN theory dark matter does not exist but is the function of two atomic processes that annihilate each other. Those being delanutrionic sub divergent processes.

[BenTheMan]

No, Jack, you're completely wrong.

[JackMuChabas]

I disagree. You use calculus which completely wrong because it's nomenclature cannot quantify quantuum theory correctly given it's latent and unherent somages.

[Severian]

Jack, this is a science site and quite a few of the people here have science backgrounds. You can't just make things up and expect to be taken seriously.

(delanutrionic sub divergent processes, lol)

[swansont]

You can't just make things up and expect to be taken seriously.

 

So simple, so true, and so applicable to too many posts.

[insane_alien]

amazing what people try to get away with. 1 too many episodes of stargate and startrek perhaps jack?

[BenTheMan]

I think he's been sniffing paint.

[DMB]

With regards the question "Where is dark matter?"

 

There appear two posts on zpenergy.com that might address this question from a somewhat helpful perspective. These posts may be regarded as speculatively "pseudo-scientific" by some here, though the writer doesn't appear interested in "overturning" any of the brilliant work already done in theoretical physics. Rather the postings ask questions that seem to recontextualize theoretical discussion, and then explore the logical extensions of some possible answers. And while "Dark Matter" doesn't receive mention by name, MasterK's willingness to ask this question has inspired some developing ideas here...

 

Here are the links and titles of the posts:

 

ZPEnergy.com - If Spacetime appears 'curved,' then what does it 'curve around' or enclose?

http://www.zpenergy.com/modules.php?name=News&file=article&sid=2509

 

ZPEnergy.com - Zero-point Ethics and Metaphysics

http://www.zpenergy.com/modules.php?name=News&file=article&sid=2508

 

-DMB

[BenTheMan]

Actual quote from the article:

 

Likening these interactions to undulations in the surface of an ocean of repressed awareness, Dog Ear'd Cosmos asks a pertinent question: if space-time appears "curved," then what does it curve around or enclose? Could "what lies beneath" the perceived surface of our Universe correlate with a "Collective Unconscious?"

 

Awesome. We are truly in the Age of Enlightenment.

[Severian]

I don't see what they have against a plain old neutralino.

[BenTheMan]

Well, it's because they never took the time to learn how to do the SUSY calculations. If you use words like ``collective unconscious'', you don't have to do any calculations. You can just spout bullshit and wave your hands.

[Severian]

I am writing a paper about the neutralino right now as a matter of fact.

[BenTheMan]

You and about a thousand other people

 

Are you grad student, post doc or faculty?

[DMB]

MasterK:

 

Have no idea what your proficiency in "doing calculations" might be... though apparently BentheMan pins his burgoning sense of "being one" on his ability to "do them." Regardless, calculations divorced from a heuristic (even artistic) appreciation for both the beauty and the short-comings of physical theory amount to sissors in the hands of a clumsy child... the child can do productive work with them, yet needs constant supervision. If the child should start carving on the furnuture with them, s(he) could use a spanking... or at least a "come to Jesus" meeting, as my agnostic dad would describe such confrontations I had with him as a narcissitic child.

 

Anyhow, should you choose to continue exposing what seems a bright and open mind here, you might consider taking some of what people have to say with a few grains of salt. And though I may very well be mistaken in much that has been said, I still appreciate the logical open mindedness with which you question current "explanations" of dark matter.

 

DMB

[Severian]

Are you grad student, post doc or faculty?

 

Faculty

 

Have no idea what your proficiency in "doing calculations" might be... though apparently BentheMan pins his burgoning sense of "being one" on his ability to "do them." Regardless, calculations divorced from a heuristic (even artistic) appreciation for both the beauty and the short-comings of physical theory amount to sissors in the hands of a clumsy child... the child can do productive work with them, yet needs constant supervision. If the child should start carving on the furnuture with them, s(he) could use a spanking... or at least a "come to Jesus" meeting, as my agnostic dad would describe such confrontations I had with him as a narcissitic child.

 

If you can't do calculations, then you can't make predictions. And if you can't make predictions, you are not doing science - just pointless navel gazing.

[swansont]

If you can't do calculations, then you can't make predictions. And if you can't make predictions, you are not doing science - just pointless navel gazing.

 

Navel gazing isn't always pointless. Sometimes it's your job (well, my job, anyway)

[BenTheMan]

Is that a government job?

[swansont]

Yes, it is. And since it sometimes involves waiting around for things to happen (or while they happen), I get to surf the web.

[insane_alien]

so that why government bandwidth usage is so high ;P

[BenTheMan]

You're not hiring particle phenomenologists, are you?