dark matter

[astromarks]

There is the galactic rotation problem, <br />You can find some info here:<br />Dark matter physics

 

[search]

"Bollocks" gents...<br /><br />I just posted something dealing with dark matter and alternative theories and as soon I finished writing it there is a new thread about dark matter. <br /><br />In that post I mentioned that it seems that the scientific community is not using its sinergies the best way and I must say that this forum is not giving the best example. <br /><br />I find great all the comments but maybe we need Sub Sections to Space & Astronomy and Ask the Astronomer to deal with this thread threath...<br /><br />Like dark matter soon we will not be able to account for all the matter in this forum...

 

[alokmohan]

Neutrinos are original candidates.They were searched in Gold mines in South Africa.My favourite candidate is ,of course,Brown Dwarf.Vote for Brown Dwarf.

 

[emperor_of_localgroup]

Thanks for the link 'docm'.<br />Photons turned into axion 'particles' by magnetic field. This is what I was waiting to hear. Now you all can dig up my now dead thread 'Is everything electromagnetic?' without laughing at me. This is just a beginning, I hope. <div class="Discussion_UserSignature"> <font size="2" color="#ff0000"><strong>Earth is Boring</strong></font> </div>

 

[ldavidcooke]

Hey Borman;<br /><br />Just a few very simple questions, if the matter that comprised dark matter surrounds the Milky-Way simply does not generate energy of it's own and if it is present as physical matter, should it not reflect or absorb and re-emit the photonic energy generated by the Milky-Way? Or maybe another way of describing it is if as you indicate that the close dark matter has been absorbed by the Galaxy, would not any matter not absorbed be in the same plane as the spiral arms? If this matter were in the same plane as the spiral arms would there not be a line, observable looking opposite of the center of the galaxy where the "dark matter" should be concentrated? By the same token if the galaxy were ellipitical then should there not be an obvious semi-spheric shell behind galaxies of this character?

 

[six_strings]

"There are recent observations from the collision of two galaxy clusters that brought some points to bear"<br /><br />Link: http://www.cnn.com/2006/TECH/space/08/21/dark.matter/index.html<br /><br /><img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[fr33dom]

I got to thinking today about dark matter. Could dark matter be super large atoms that have expanded so large we cant tell thier structure because its too big and too far apart? Maybe there was much matter before the Big Bang that we cant detect because the scale difference is so vast. As our universe expands, the atoms also expand until they will become the size of galaxies. If the number of atoms from previous big bang events hasnt changed, only the scale, we may not be able to know if the atoms from previous big bangs exist or not. Perhaps dark energy also comes from the same source. Trillions X ?exp. of atoms, superlarge, drawn together by gravity causing a field of energy pervading space. Superlarge atoms would also roll right through a galactic collision and give the same gravity signature as the dark matter did on the photos recently.<br /><br />If any physicists or Astronomers think this may be a valid idea, please post, and if it is impossible, please post why.<br /><br />

 

[billslugg]

fr33dom<br />Why would largeness be an impediment to observation?<br /> <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[enigma10]

I've often felt large women to be an impediment to observation.<img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>

 

[fr33dom]

Because we couldnt tell if this particle was in the room with us if our room represented .001% of its total volume. The particles would be much more smeared than the itty bitty particles. THey could be so big that many of the forces may not apply as well as they use to, like interchange of energy. Imagine if a charmed particle was the size of Everest. It would be hard to manipulte that particle. It would give an overall field effect I would imagine, over the volume of the atom. Not only that but possibly this same field type effect could be causing up to increase velocity as time goes on. It could be dark matter gravity from an number of previous big bangs, all the atoms just floating out there, some the size of solar systems or bigger. IT could create an outward pull to pull us along.

 

[ajna]

I read in Brian Greene's Fabric of the Cosmos that for a particle to inhabit one of the smaller curled-up dimensions (of the 11-dimension M-theory) its position has to be determined within a very tiny space, which creates huge uncertainty in its velocity, and because it has a small wavelength it is highly energetic, making it very tiny but very massive. It is not <i>directly</i> detected in 4D spacetime because its energy is so high it doesn't 'live' in 4D, yet we see the effects of this particle (possibly) in dark matter or dark energy. <br /> With regards to large atoms, the electron haze would be so far from the nucleus the atom's time frame would have to speed up relative to when it was smaller to keep the electrons in synch with the atomic quantum. To speed up an atom like this would change its spacetime dimensionality and so its position would change also. fr33dom, I think you've cottoned on to how to move atoms (objects) from here to there in the blink of an eye. But only spacetime expands, not electron clouds (or planets or suns etc) so atoms remain as they are in expanding spacetime, which is why things are getting farther apart.

 

[alokmohan]

Brown dwarfs are possible candidates.

 

[serak_the_preparer]

Black hole waltz?<br /><br />Space telescope spies dark matter by Geoff Brumfiel (Nature)<br /><br /><i>Astronomers have used telescopes on Earth and in space to nail the precise position of a mysterious, dark object at the outer edge of our Galaxy. The work could be an important step in understanding so-called dark matter — mysterious material that makes up about a quarter of our Universe.<br /><br />Most dark matter is believed to be in the form of subatomic particles that don't interact with regular atoms. But as much as 20% could also be in more traditional things that don't emit light, such as black holes and clouds of gas that never became stars....<br /><br />Based on this delay </i>[between ground-based observations of the MACHO and those made by Spitzer]<i>, the team calculated that the object lies some 16,000 light years away, putting it squarely in the Milky Way's halo. Dong suspects that the object is a pair of relatively small black holes orbiting each other....</i><br /><br />Cool accompanying graphic: By viewing an object at the edge of the Galaxy from two points 70 million miles apart, you can pinpoint its position. (NASA/JPL-Caltech/T. Pyle (SSC))

 

[serak_the_preparer]

Enough about the MACHOs. More food for thought:<br /><br /><br />High-energy detectors might find 'unparticles' by Philip Ball (Nature)<br /><br />13 June 2007<br /><br /><i>. . . If energies were a thousand times greater, a new suite of particles would predominate, as is thought to have been the case in the early instants of the Big Bang. The Universe would then look very different.<br /><br />Georgi's unparticle stuff doesn't behave like that, he argues in Physical Review Letters1. You can boost energy levels as much as you like, and the unparticles would look just the same. This property is called 'scale invariance'....<br /><br />The answer, </i>[Howard Georgi]<i> says, is weird: ordinary particles interacting with unparticles would behave as though they were interacting with a fractional number of massless particles — a bit like interacting with, say, five and a half photons....</i><br /><br />(What would the track of an 'unparticle' look like? No one knows.)<br /><br /><br />Tech researchers help find new sub-atomic particle by Dave Guerin (Louisiana Tech University)<br /><br />June 14, 2007<br /><br /><i>. . . Details of the discovery will be presented at a special Fermilab seminar at 1 p.m. Friday, June 15. The DZero experiment reported the discovery of the particle in a paper submitted June 12 to Physical Review Letters, the Journal of the American Physical Society.<br /><br />A news release from Fermilab provided the following information:<br /><br />• The newly discovered heavy particle is a baryon known as the "cascade b."<br />• "A baryon is a particle of matter made of three fundamental building blocks called quarks. The most familiar baryons are the proton and neutron of the atomic nucleus ... Baryon</i>

 

[onesimple]

There is no dark matter at all<br /><br />Galaxies<br /><br />Galaksit rotating like wheel , in other words farthest stars go around the centre of galaxy almost quickly as stars of the galaxy centre. Current physics does not understand, how so said. Force of gravity works, but in any case it is already had time to take according to to its theories, so said. dark substance , whereby this in question power is also. In galaxies namely is not enough bulk, which should galaxies of wheel. Ten times more bulk inside the galaxy , as nowadays is observed, would be enough to keep also farthest stars of galaxy on their orbits in noticeable speed, if force of gravity so even exists.<br /><br />My thought does not need dark ingredients to explain, why galaxies are observed rotate like wheel. Stars of all galaxies push and so forth from the galaxies' centres in accelerating at speed expanding with the same three-dimensionally in the accelerating at speed. It is absorbing, that from common red move of light are in the noticeable accelerating expanding, which is for the time being interpreted space to be accelerating expanding.<br /><br />Stars themselves open as the energy wave, by which they push each others and so forth from one another in the same proportion as expand, and in the galaxies' centres are colossal three-dimensionally expansive energycentrums/ black aperatures , from which the opening energia-aalloi has atom personality. All energy of the visible macrocosm rubs against to the coming energy waves about 11 year between, and sometimes well against energy compaction which is in the coming energy waves hits the galaxy to the centre and clean from the big area new three-dimensionally expansive atoms to their presumably towards black aperature, which after to the cleaned area outside, outwards in the work base wave be expand atoms come push each others towards produce cleaned areas forward to be going during the business , whereby there forms new energycentrums, which to inside pr

 

[MeteorWayne]

Sorry, still can't understand what you are trying to say.<br /><br />From an english speaker's point of view, it is gibbereish. Sorry <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[Swampcat]

Looks like a Babelfish translation. <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[eaglesindiana]

According to my calculations about only 5% is dark matter 1% is matter and 96% is dark energy

 

[timejump]

im sure this question has been asked before but.....<br /><br />how do we know dark matter exists.

 

[yevaud]

Simple:<br /><br />A PhD Astrophysicist, Vera Rubin, was working for the Carnegie Institute many years ago; she was specifically looking at the rotational rates and dynamics of Galaxies.<br /><br />She noticed something VERY odd: with every Galaxy imaged and analyzed, the rotational rate at the edge of the Galaxy was pretty much the same as the rotational rate near the center of the Galaxy. I mean EVERY Galaxy, no exceptions.<br /><br />Physically, this is not possible. The rotational rate at the fringe should be much lower than at the core.<br /><br />Hence, Dark Matter: a source of unseen gravitational influence that has caused the increased rotational rates.<br /><br />Does this help? <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[kyle_baron]

<font color="yellow"><br />how do we know dark matter exists. </font><br /><br />Because Wiki says it does: <img src="/images/icons/wink.gif" /><br /><br />http://en.wikipedia.org/wiki/Dark_matter <div class="Discussion_UserSignature"> <p><font size="4"><strong></strong></font></p> </div>

 

[kyle_baron]

<font color="yellow"><br />A PhD Astrophysicist, Vera Rubin, was working for the Carnegie Institute many years ago; she was specifically looking at the rotational rates and dynamics of Galaxies. <br /></font><br /><br />Fritz Zwicky (1933) predates Miss Rubin by a number of years:<br /><i><br />The first to provide evidence and infer the existence of a phenomenon that has come to be called "dark matter" was Swiss astrophysicist Fritz Zwicky, of the California Institute of Technology (Caltech) in 1933.[5] He applied the virial theorem to the Coma cluster of galaxies and obtained evidence of unseen mass. Zwicky estimated the cluster's total mass based on the motions of galaxies near its edge. When he compared this mass estimate to one based on the number of galaxies and total brightness of the cluster, he found that there was about 400 times more mass than expected.</i> <div class="Discussion_UserSignature"> <p><font size="4"><strong></strong></font></p> </div>

 

[yevaud]

Yes, Zwicky did, but it was considered non-interesting and never actually pursued far. Rubin quite literally stumbled onto it and pursued it, leading to the theory of Dark Matter.<br /><br />Thus, while Zwicky pointed the way by theorizing, Rubin was the one who actually "proved it" (so to speak). <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[vandivx]

nah, simply times were more modern - more acceptable of odd findings as well as more advanced techniques were in place in times of Rubin to more conclusively show that something doesn't add up up there in galaxies, also Zwicky's being sort of black sheep among scientists around him led to discounting of his findings (him being the oddball he apparently was was only reason he came out with his results, others would believe they made some mistake if they found themselves in his shoes but Zwicky apparently didn't fear coming out with his controversial findings)<br /><br />he should be taken to be the discoverer of the phenomenon IMO and that's how history books show it from what I have seen<br /><br />strictly speaking, it may turn up that dark matter doesn't exist and that the phenomenon observed in galactic motions (which does exist and which led to dark matter postulation) might find explanation in some alteration of gravitational force<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[yevaud]

True, although if you want to strictly adhere to that, then String Theory was actually discovered by Euler (the Euler Beta Function) in the mid-1800s (this is what Kaluza-Klein, then Yang-Mills, the everyone following is based on), and Einstein didn't really do anything, since his theorizing was based on other people's work.<br /><br />And besides, as I'd mentioned, pursuing that line of reasoning during that era wasn't a "hot" topic. He thought about it, theorized about it - but never pursued it further. And there it sat for several decades, an odd fact.<br /><br />None of which discounts Zwicky's work. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>