Dark matter Definition and 935 Threads

https://www.inverse.com/article/24863-dark-matter-might-be-smoother-than-we-thought Scientists have yet to actually observe dark matter in the flesh, but most research up to now posits it’s the kind of stuff that clumps up and aggregates into unwieldy masses around the universe. New research...

This is a request for a good reference. I'm doing a report on dark matter and am wondering if there's any recent references that collects a bunch of galaxy clusters, their dark masses and the radius of the cluster. Preferably in a table that I can shred or download but I'll copy if I have to...

In 2005, A. Vikhlinin et al. made a hydrostatic equilibrium study - https://arxiv.org/abs/astro-ph/0507092 - of some dozen galaxy clusters. These hydrostatic studies are useful because they don't contain the M/L assumptions of other methods. From this document, I'm trying to extract the dark...

This paper favors a mixture, but there are many papers that predict Cold dark matter, is there a particle that can be ruled out, or pushed to the back of favored particles. arXiv:1611.09362 [pdf, other] Hints against the cold and collisionless nature of dark matter from the galaxy velocity...

It seems to me a possible explanation of the dark matter effect could be as follows: Thorne and Misner (p. 719 in Gravitation) note that the Hubble expansion is anisotropic. Empty space expands but the gravitationally bound space within galaxies doesn't expand. This should obviously produce...

How does dark matter suppress baryonic osculations?

https://www.sciencedaily.com/releases/2014/09/140908204603.htm According to this article dark matter is warm, and provides a mechanism for showing the lack of satellite around the milky way. Date: September 8, 2014 Source: Royal Astronomical Society (RAS) Summary: Scientists believe they have...

I am trained in aeronatical engineering, spent a number of year supporting sounding rockets in the exploration of the Upper Atmosphere. Retired 16 years ago. Am interested in General Relativity and Quantum physics. Looking to explore and understanding of entropy... Black holes... Etc.

HI, I am looking to find a table of galaxies, their masses, types, black hole mass and dark matter content. Does anyone know if such a place exists anywhere on the internet? I'm trained in physics but is not a physicist - more a hobbyist. Any suggestion that you might have will be greatly...

Several articles I've read say that the basis for BBN is that we know how particles react here on earth, so we can extrapolate that and make precise predictions for the composition of the universe at a given energy level. For example, at 100 Billion K, we have a pretty good idea how neutrons...

Hubble Reveals Observable Universe Contains 10 Times More Galaxies Than Previously Thought http://hubblesite.org/newscenter/archive/releases/2016/39/full/Change the data to fit model ?

can dark matter explain Tully-Fisher relation, or is modified MONDlike gravity a better explanation for this? new paper The Radial Acceleration Relation in Rotationally Supported Galaxies Stacy McGaugh, Federico Lelli, Jim Schombert (Submitted on 19 Sep 2016) We report a correlation between...

Is it conceivable that dark matter only interacts gravitationally? Is SUSY losing her charm? I truly want to know what the experts think. I'm not qualified to have an informed opinion about this subject.

Why gravitational force is attractive? Some where it was written that gravitons are hypothetical particles which mediates the force of gravitation, and it has a spin of 2 , and Quantum field theory had proved that any particle of spin 2 characteristic will always mediate attractive force...

Can black holes convert dark matter into matter and vice versa? Presumably, a black hole can gain its mass from eating normal matter, or dark matter, or light. Then, it will eventually evaporate into Hawking radiation. I guess the Hawking radiation should include light as well as both matter...

I'm a mathematician, not a physicist, so I apologise in advance if I'm just showing my ignorance here. My only source of information on dark matter is popular science texts, like New Scientist. One thing that is never explained is how it gets to aggregate around galaxies. Lacking the ability...

What if dark matter is just regular matter that's not very well lit up? What do you think?

Hi, I'm interested in research on the formation of dark matter halos and was hoping that I might, in the future, run an N-Body simulation on the subject. However, I do not have any experience with N-Body simulations. I only know C, but I am learning Python. So, does anyone have a suggestion for...

recent results on dark matter searches LHC has produced no dark matter candidates, esp neutralinos LUX/panda has found no candidate WIMP events axion dark matter searches have come up empty ice cube sterile neutrinos have come up empty Ethan Siegel, Contributor The null detection is...

At last a theory of Dark matter that can be tested, is there a fundamental reason why this theory may be true? Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according to a paper published in...

this was widely reported in the past, but not commented on here https://www.sciencedaily.com/releases/2016/04/160422115320.htm based on http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.161101 Search for Spectral Irregularities due to Photon–Axionlike-Particle Oscillations with...

For the universe extra source of gravity, why don't they propose some kind of field connected to our matter instead of dark matter?

The negative findings of the Large Underground Xenon (LUX) dark matter experiment, which is a 370 kg liquid xenon time-projection chamber that aims to directly detect galactic dark matter and which were published at the international dark matter conference in Sheffield, UK, raises questions...

widely reported in all science channels LUX Dark Matter Experiment Ends With No WIMPs Found what are the ramifications to SUSY QG string theory LQG MSSM dark matter etc based on this results? how likely is dark matter WIMP hypothesis in light of this null result, and of neutralinos Does this...

There are links in the article to more science-oriented reports. http://www.csmonitor.com/Science/2016/0715/Scientists-create-huge-3-D-map-of-universe-validating-Einstein-s-theories That would be a great use for some of those Virtual Reality goggles.

are gravitational waves somehow connected with dark matter??

So if space is a vacuum, how can we have dark matter? What does it contain that means that space still acts like a vacuum?

The dark matter is described as something which can't be detected in any way except for its gravitational attraction. My question is: may the dark matter be identified with gravitational field generated by the presence (for short times) of matter and anti-matter which is continually created and...

Is the "missing mass" the mass of the photons connected to and neighboring the matter which are displaced by the matter?

https://www.sciencedaily.com/releases/2016/06/160615134951.htm From science daily Date: June 15, 2016 Source: Johns Hopkins University Summary: When an astronomical observatory detected two black holes colliding in deep space, scientists celebrated confirmation of Einstein's prediction of...

widely reported in the news is a second observation of 2 black holes gravitational waves. also reported are its implications Science World Report-Jun 15, 2016 Astronomers have reportedly started to think that dark matter could be made up of primordial black holes. According to Alexander...

I read that the cold dark matter model best fits the cosmic background radiation spectrum. I am puzzled by why most of the mapping of the distribution of dark matter shows it to be in halos about galaxies, rather than evenly dispersed with ordinary matter. The question arises from this...

As title really, just an idea I had from various videos and articles I've read as an enthusiast of all things physics. Some supporting sentences from my somewhat ignorant but perhaps not-entirely-wrong thinking: - The velocity of stars around the periphery of galaxies, I've heard of a theory...

I thought this may be interesting, the decades old search for Dark Mater. arXiv:1605.04909 [pdf, other] A History of Dark Matter Gianfranco Bertone, Dan Hooper Comments: 86 pages, 8 figures Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA)...

I am more familiar with quantum physics than cosmology so it occurred to me that I hadn't heard anyone talk about the question of symmetry with respect to dark matter. If its influence is restricted to the disc of a galaxy, but it is particle-like in structure than symmetry is violated isn't...

What is meant by the statement by Harvard scientist Lisa Randall that dark matter carries five times the energy of ordinary matter? Does E=mc2 not apply to dark matter? Does the statement refer to ordinary energy or to dark energy?

The graph I have made of Average Orbital Distance from the Sun vs. Average Orbital Velocity illustrates a decreasing exponential function. How, if it does, would this suggest that there is dark matter present in our solar system?

What is dark matter? What are the effects of both dark matter and dark energy?

Dark Matter is every where and always passing threw us right? It apparently hold everything in place in our universe. We know it there but can't detect it. We see the results, but we don't really see who's responsible. What If dark matter was basically a different type of gravity? And the...

Hi all, I've just been made offers to two different institutions - one to study General Relativity and Early Universe Cosmology, and one to study particle physics phenomenology and dark matter at PhD level, and I'm having a hard time choosing! Relativity and Cosmology is Queen Mary University...

We assume that Lambda, the cosmological constant or "dark energy" is constant in all of spacetime (at least all of space). But what if it was not? A lower value of Lambda in a certain region of space would mean that space's tendency to expand there is lower, and that might have the appearance...

Has there been any theories proposed that model Dark Matter as just the pressure from vacuum fluctuations? It would be just a big cosmological-scale version of the Casimir Effect, where instead of using a couple of plates separated by microns, we're using the gravity wells of galaxies to create...

In 2011 Dr. Gerald Guralnik of Brown University was involved in an ongoing Dark Matter Detection experiment, perhaps LUX? It was an international collaboration involving underground detectors. He was certain DM would be detected in 5 years - i.e., now. I was dubious, so we bet "bragging rights"...

Are there any hypotheses on dark matter being gravity force in the higher dimensions predicted by string theory? I would like to read such hypotheses.

It seems that the most popular hypothesis is that dark matter consists of WIMPs. Can the existing data be described with sterile particles rather than ones that interact through the weak force? Is the only reason to prefer WIMPs that they are predicted by SUSY? (To me, as a nonspecialist, SUSY...

I've been looking over the idea of the multiverse recently. I am trying to grasp exactly why so many physicists believe in the idea when it seems more philosophical than scientific. Are there any good indicators pointing towards the theory from QM or GR? The gripe that I also see with it...

Since we think that 85% of the matter in the universe is Dark Matter, does it follow that around 85% of the mass of a typical black hole should be of dark matter origin? If not, why not? And if so, black holes are defined by only 3 parameters, mass, electric charge and spin. As far as we can...

A lot is being written about the recent aLIGO observations and in general the implications of GW research for our scientific understanding of the universe. We read about mostly 2 grand areas where GW research can provide novel knowledge. The astronomical / astrophysical area (i.e. mapping...

I've read the postulate that there could be a huge spherical dark matter halo extending far beyond the edges of the Milky Way. However, according to Newton's shell theorem, there is no net gravitational pull within a shell. How do they arrive at the conclusion of a halo so huge?

As humans, we intuitively tend to interpret the things we see in our local time frame. However, the rate at which time flows at any point (or time) in the Universe is affected by the strength of the gravitational field at that point (or time). Hence when we see distant events through our...