Dark matter Definition and 935 Threads

Authors propose solution to dark matter and alternative to MOND. Higher Order Curvature Theories of Gravity Matched with Observations: a Bridge Between Dark Energy and Dark Matter Problems http://www.arxiv.org/abs/astro-ph/0411114 Higher order curvature gravity has recently received a lot...

I admit that dark matter is apple pie and motherhood. I love Dark Matter just like you. But this paper has been accepted for publication in Physical Review Series D they did not post the preprint at arxiv until it had passed peer review and been accepted. this is a 72 page paper. we cannot...

http://www.bell-labs.com/news/2000/may/11/1.html has a number of links (bottom of the page) very relevant to observational studies of the distribution of dark matter. In particular, the last three links: http://dls.het.brown.edu/, a programme to create maps of the distribution of dark...

I been thinking... ...anything falling into a black hole and assuming it gets reduced to it's basic "string" then by way of the spiralling effect of the black hole in an ever decreasing vortex becomes a very long very dense connection of strings only a Planck unit in diamater but infinitely...

Fantastic amount of information contained in this paper: http://uk.arxiv.org/PS_cache/hep-ph/pdf/0404/0404175.pdf Its long, but everything you 'dont' know about Dark Matter is contained in this interesting overview. Takes a while to load because of its size, but its well worth it, authors...

I'm reading Hawking's take on ground state energies never being zero, and he adds an interesting point. He said based on the casimir effect the denisty of ground state fluctuations (wavelengths) are less by a finite amount between the plates, causeing them to draw together. To me this explains...

Are electron clouds formed because the electrons are traveling near the speed of light? If so, why is a "cloud" formed --- a colloid, that is. If it is possible to form a more uncommon type of matter like a colloid by traveling near the speed of light, could you possibly form dark matter by...

Could anybody list (and write a few explanatory words about) the various theories which explain the origin of the dark matter and the dark energy? Thanks!

My understanding is that dark matter surrounds a galaxy in a spherical formation. What I don't understand this type of dark matter can explain the non-Kepplerian rotation of the galaxy. According to Gauss's law, in a spherical shell, only the mass inside the orbit of a body has a net...

dark matter --- dark energy Can anyone explain to me the difference between dark matter and dark energy ? What are their proper relations to the expanding universe? Dark matter should be taken into account because we know not enough matter that can be held responsible for keeping...

Why does light have a speed? Why does Gravity (Gravitons) have a speed? There is nothing to slow them down... (Or is there!?) E.g. Sounds in water have a speed because of the matter they travel through. Light traveling through different materials will be effected on how fast it can travel...

This is just an idea but if galaxies have or develop a black hole in their center couldn't it be possible that darkmatter uses the electromagnetic field of the black hole to keep the galaxy in place and also keeps it from colliding with another galaxy. I can't really explain what i am thinking...

If Dark Matter was the mirror twin to Dark Energy, then normal matter would be siamese twins?

i'm interested in any alternative theories re: dark matter...is it possible that we simply have misunderstood gravity at these distances? it seems strange to me that we look for symmetry in the physical laws and so we see something we can't explain using the law of gravitation and our...

evidence against existence of dark matter?? Hi have there been any recent publications that u guyz may have read that are against the idea of dark matter and have other theories on wot keeps galaxies in orbit.? I really need ure help coz its for an essay that i have been working on. cheers.

Heya! I need some good links to articles on dark matter that are easy to understand and are worth reading. Stuff on neutrinos,, hot dark matter, cold dark matter...and mass to light ratios. tanxy.

Does the path of light from distant galaxies curve according to with or without dark matter and energy?

Space is filled with gravitons moving in every direction. These gravitons push masses together and cause "attraction". When gravitons approach a spiral galaxy parallel to its plane, they get pushed together and concentrated by the magnetic field lines of the galaxy. As they double their...

Greetings, When I was still in college, a professor commented that it was possible that gravity was not a force. He based this on the observation that gravity didn’t seem to have opposite charges. The force of electricity has positive and negative. Gravity does not seem to have such...

I have read that the Dark-Energy may be a consequence of Pressure from outside of the Universe. The presence of a spin zero field (higgs-field) seems to make this idea really interesting. Negative pressure was postulated by Poincaire, Dirac. Accordingt to the author, negative...

This paper: http://www.edpsciences.org/papers/aa/pdf/press-releases/aa0959.pdf ...press release: http://www.eso.org/outreach/press-rel/pr-2004/pr-08-04.html suggests that the kinematic heating (statistical dispersion of velocities in the perpendicular plane to the galactic plane) of...

i don't understand how dark matter acts upon the rotation of a galaxy. galaxy rotation doesn't work the same way that solar system rotation does in that it's not a simple gradient of further planets rotate slower, right? nor is it further planets rotate faster, like a vinyl record...i take it...

Dark matter?? What's that?

http://physicsweb.org/article/news/8/2/4 6 February 2004 Many astronomers believe that the universe is dominated by cold 'dark matter' and 'dark energy' - a view that has been confirmed by recent measurements on the cosmic background radiation. Now, however, a group of astrophysicists in...

I am not sure what forum category this should go in, but since Cahill's paper (see abstract and link below) claims to be the first evidence for discrete space, which of course supports LQG, this may be the appropriate location. I searched the Physics Forum for Cahill and got zero hits. His...

SDSS observations, supported by Subaru and Keck, confirmed that a massive cluster of galaxies is the gravitational lens for a quadruple-quasar image, the widest pair being separated by >14" (arc seconds). In addition, "[d]iscovering one such wide gravitational lens out of over 30,000 SDSS...

What I've heard is that galaxies are spinning weirdly. They are spinning on the outer regions too fast. Also that the velocity of the outer stuff is 10 times greater than the gravitational force of our galaxy itself. So we say that there is this dark matter that we can't see at any wave lengths...

After recently seeing Brian Greene's "Elegant Universe," I was struck by an idea - maybe not an original idea, but an idea nonetheless. If gravity is a weak force because it is not stuck to the "brane" of this universe, then gravity from our universe can influence others and vice versa from...

Scientific American, March 2003 - "dark Matter" The Search for Dark Matter" Scientific American March, 2003 Page 52: "For 70 years, astronomers have steadily gathered circumstantial evidence for the existence of dark matter, and nearly everyone accepts that it is real. But...

I went to a cosmology seminar recently. It was mostly for fun, but if you complete a take home exam you get a tiny bit of college credit for it. Things were going along fine until I ran across the last two questions: How was Dark Matter just discovered and when did this happen? What...

Knotty Jets, the Tell Tales for Early Dark Matter and Spiral Galaxy formation. It is proposed that the new paradigm for Black Holes with a nuclear particle content, see http://home.planet.nl/~vuyk0022/ , lead to a 2 stage semi-cold Black Hole evaporating Big Bang see...

Joe Silk, who is world class, is one of the co-authors of this preprint http://arxiv.org/astro-ph/0309686 "MeV Dark Matter: Has It Been Detected?" the paper is dated 1 October of this year. A sharp line of gammaray from near Milkyway center has been observed at 511 keV energy. A...

Greetings ! I wonder if we really need to pursue just the dark matter direction to explain why galaxies turn the way they do and the whole cosmology part about the form of Universal space-time. Has there been an attempt to explain the motion of galaxies by adding another Universal law...

People have "invented" it out of a need to explain large scale motions in the Universe, but is it really there? Might there be other explanations? Here's an interesting page about it. http://www.astro.ucla.edu/~agm/darkmtr.html You can get more by putting "dark matter" into Google or...

So, it seems that Dark Matter now takes up most of space. What does that mean? What exactly is Dark Matter and why did we miss it before? How will change astronomy? Educate me on this please.:smile: Thanks.