Dark matter Definition and 935 Threads

Dark matter island in the Pacific?? http://www.bbc.co.uk/news/world-asia-20442487 Could this island be really there but made of dark matter? :-p

Are there any theories based upon Dark Matter (DM) being a precursor or sublayer or ground state to Observable Matter (OM)? Pre-Big Bang? Galaxy distribution linked to DM tendril intersections is consistent with DM providing a pre-existing structure. Any theories based upon DM interactions...

Hi; Forgive me if this topic has been covered elsewhere; I'm new here and didn't find an answer to my question by searching the Higgs. With the potential discovery of the Higgs as announced this past July by CMS and ATLAS the one thing that I'm not understanding is why isn't the Higgs...

Simple "Beginner" Dark Matter Question Ok, for some reason I can't seem to get this straight, probably because its so obvious nobody spells it out. Its more a question of terminology than the real mystery of dark matter, but its proving an obstacle in my efforts to catch up on a subject i have...

I appreciate that the holographic principle is just a theory, but if I accept it and the related aspects of string theory, does it do away with the need for dark matter (since I think that the mass approaches infinity as one changes the reference frame in which one observes the the mass)...

The existence of dark matter was inferred in studies of the unaccountable behavior in the rotation of observable matter in distant galaxies. Dark Matter is ubiquitous. Does this imply that Dark Matter is uniformly distributed locally with respect to us, since we cannot detect any influence of...

From previous answers - according to the general theory of relativity, kinetic energy contributes to gravitational mass. A body in motion posseses kinetic energy plus mass. Energy and mass are equivalent under GR. Particle colliders routinely confirm this prediction. Crash two particles together...

If DM is immune to the electromagnetic force but not to gravity and the universe is homogenius, would we expect the find DM at the centre of normal matter bodies such as stars and planets trying to form black holes?

www.sciencedaily.com/releases/2012/09/120906092059.htm http://arxiv.org/abs/1206.5078 Very interesting article, has anyone seen this or looked at the paper? I don't have GR knowledge to make sense of what's going on. "The difference between the new field equations and Einstein's equations is...

Hypothetically, if we weren't receiving all the light from a galaxy, is it possible that this would reconcile the gravitational shortfall we perceive? Would it not also explain the gravitational lenses that we attribute to dark matter (since we are not receiving all the light to represent the...

Did anybody else hear the news? A recent paper examines the derivation of Einstein's field equations and proposes that the original assumption of a divergence-free energy-momentum tensor may not be valid anymore due to the discovery of dark matter and dark energy. The authors derive new field...

NASA yesterday on the 29th published a survey in which they claimed the detection of many new stellar objects. The press release continues to say this includes super-massive black holes 2/3 of which were previously undiscovered. This is a lot more mass than we previously knew existed. What are...

What is dark matter? I understand this is a huge topic, so feel free to refer me to a book or link. Thank you.

Before i begin, i will note that i truly don't have any idea of what I'm about to ask, but the questions elude me so ask i must. Firstly, Dark matter: finding it on earth. I've just finished watching a documentary on mapping our universe and within the program was shown a theory of trying to...

Has dark matter been observed to exist in quantities that correlate with the apparent observed mass or overal volume of gallexy/ star clusters? I'm wondering if dark matter is distributed in relative even amounts based on given characteristics or if it is thought to be random/unknown.

There are several types of evidence for DM and Helsinki scientist Matts Roos provides a 39 page overview listing and summarizing each kind. It's a useful article. He gives graphic figures to illustrate each type of evidence. http://arxiv.org/abs/1208.3662 Astrophysical and cosmological probes...

The situation is this: In a neutron star the Coriolis force induces Rossby waves, just like on Earth. These are waves with very long wavelength -- like halfway around the Earth -- and very large volume but very little amplitude, like fifty meters. On Earth they have a big effect on climate...

Plenty of Dark Matter Near the Sun http://www.sciencedaily.com/releases/2012/08/120809090423.htm Evidence for dark matter near the sun "We are 99% confident that there is dark matter near the Sun," says the lead author Silvia Garbari. In fact, if anything, the authors' favored dark...

If there is Dark Matter in the solar system, the erosion of comet with Dark Matter will be happen? A comet's main component is water, water has many nucleus per unit volume. and comet speed is very high. So. comet has high collision frequency with Dark Matter per time. Total energy for the...

I didn't know where to post this. Astrophysics? Particle physics? I know very little of dark matter. I've read that it's sometimes supposed to interact only gravitationally, and also that weakly interacting particles have been proposed as its constituents. Is there a reason why they should...

A few weeks ago I stumbled upon an MIT Technology Review article about a DNA-based dark matter detector. As a biologist I thought the idea was strange, since I didn't see how DNA would interact with dark matter in a way that a more easily manufacturable material such as silicon wouldn't. I put...

I know these are ambiguous questions and am probably opening up a complex can of worms. I figure if we know how much of the universe is composed of dark matter and it's effects, we should also have an idea about its mass from its gravitational pull. Also I figure since truelly empty space also...

Hi, I was at a presentation re there recent anouncement by CERN, and the distinction between matter / dark matter / dark eneregy (matter versus the 96% of the universe that we don't know about) was repeatedly made. Given the findings relate to a particle with mass / properties not previously...

Hey folks, so perhaps some of you may have heard/read of Dietrich, et al, recent paper on dark matter "tendrils" being "directly detected" between the galaxy clusters Abell 222 and Abell 223 (see a synopsis by Nature here: http://www.nature.com/news/dark-matter-s-tendrils-revealed-1.10951). My...

How strong is the influence of dark matter typically at the periphery (50.000 LY away from the center) for example in the Milky Way I mean is the Acceleration Due to Gravity (due to dark matter) (typically) 80% - 85% - 90% - 95 % - or 97% stronger as the Acceleration Due to Gravity caused...

I've thought about dark matter and I'm wondering if it could possible be made up invisible bouond states of ordinary matter? Wikipedia says "According to consensus among cosmologists, dark matter is composed primarily of a new, not yet characterized, type of subatomic particle." But why a...

anyone read this article about latest relevation about dark matter? any thoughts? http://arstechnica.com/science/2012/07/dark-matter-is-the-thread-connecting-galaxy-clusters/

Homework Statement Evidence for dark matter comes from “flat” rotation curves of galaxies. Assume that the observed matter moves in circular orbits about the center of the galaxy and that the velocity of the matter as a function of the radius v(r) is a constant. Also assume the...

Since light has gravity, and there is an abundance of it in any given space (this is easily observable by being at anyone spot in space with objects around you), would it be possible to explain what 'dark matter' seems to be?

I've heard that most of dark matter is located in the outer portions of galaxies. If that is so, wouldn't the gravity from the dark matter tend to pull the galaxies apart?

What are your personal opinions ??, Do you guys think gravity is just not fully understood that is why we can't explain certain events or DM is the probable answer to these discrepancies ? I personally don't think we need to create a somewhat imaginary matter (dark matter and dark energy) to...

Could a "Black Hole" be the cycle of "Dark Matter" powered by "Dar Energy:? Could the "black hole" be like a cycle for "dark matter". So let's say "Dark Energy" is what transports "Dark Matter". So all a black whole is, is a huge amount of energy pulling in "Dark Matter" and pushing it out to...

Hello, How could SUSY provides a candidate to dark matter since it would only appear only above the TeV scale? The galaxies' environments is at such energies? Thanks

The Reference Frame: A confirmation of the 130 GeV dark matter-like bump - Lubos Motl [1204.2797] A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope - Christoph Weniger [1205.1045] Fermi 130 GeV gamma-ray excess and dark matter annihilation in...

If this is a stupid question, just tell me. As I understand it, even forms of pure energy can create a gravitational effect in high concentrations due to E=mc2. Would this have enough of an effect to create some of the anomalies prompting the search for DM, or has this already been taken into...

Unsurprisingly, the conclusions of of Bidin, et al, on the apparent lack of dark matter in our galactic neighborhood have been challenged: On the local dark matter density http://arxiv.org/abs/1205.4033

Whenever physicist talk about dark matter they always seem to be implying that dark matter is one particle. Does this have to be the case? Could there not be many particles that are heavy, slow and with no electric charge that could all be varieties of dark matter.

Hello every one! How many of you have learned about the unification of dark energy and dark matter? I'm doing my research regarding the Chaplygin gas and I've come across this research paper. arxiv.org/pdf/grqc/0202064.pdf At the end, they solve the equation 36 (3/2*ab′′ + (1 − w)ab′ −...

Hi, I hope you can help me. I am a physicist but not a researcher and have currently not the time to study many papers about the subject of dark matter. What I would need for deeper thoughts is an expansion in a series of the Newton law for cases where it has been measured that star rotation...

I know that we don't know what dark matter is but according to observations, dark matter is there. I also knew that the reason why we know dark matter is there is because the universe is supposed to slowly become more compact, but the reality is that its doing the exact opposite, its expanding...

I'm becoming more and more convinced that light isn't the only particle that can interfere with itself, and that the behavior may instead be a function of a particle's level of interaction. The multi-galaxy collision we witnessed not long ago may have been the first time we've had the scale...

Think "gravity waves", emitting from let's say a black hole. It's an uneducated hypothesis, but why not?

Dark matter was introduced in order to make General Relativity (GR) compatible 1. with the rotational speed of galaxies 2. and the relative movement of galaxies in local groups. A new study ” has mapped the motions of more than 400 stars up to 13,000 light-years from the Sun. From...

I am 9 years old. Can anyone tell me the answer on this one?

Serious Blow to Dark Matter Theories? http://www.eso.org/public/news/eso1217/ http://www.eso.org/public/archives/releases/sciencepapers/eso1217/eso1217.pdf

If our regular Energy can spontaneously turn into matter (for instance an electron and a positron pair OR, more rarely two electrons pair) why can't Dark Energy turn into Dark Matter particles? If that's what actually happens then wouldn't the universe eventually decelerate expansion...

Namaste, Do we understand why light doesn't interact with dark matter? If a photon were to collide with a dark particle, would they be unaffected?

Are there sky surveys that perform gamma-ray absorption spectroscopy? I was wondering if dark matter might absorb gamma radiation. I have done a simple Bohr-atom type calculation assuming a dark matter model of a bound state of a North and South magnetic monopole and found a Rydberg energy...

Hi! As i said in the topic i am still very new in the field, so if my questions are stupid and just a waste of time i apoligize. The stuff i know I've learned by myself so there are gaps. Anyway, onto my question: Speed of Light(C) travels at 3*108m/s in a vacuum, but when traveling...

I'm putting together a research paper and a 45 minute presentation for an undergrad senior project. My chosen topic is dark matter. I'd like to get some more information and was wondering if anyone had suggestions. My presentation structure that I envision is something like this -Intro...