Is dark matter particulate?
453562
We don't (as yet) know what dark matter is composed of. It certainly is *not* ordinary matter since it is known not to be composed of baryons (like protons and neutrons). While neutrinos are certainly *part* of the dark matter, there are not enough of them to account for all the dark matter we know exists. Other suggestions are particles called axions, but nothing is certain in this regard.
1172316
f there were plenty of these, gamma and x-ray astronomers would long since have detected the annihilation 'lines' at 511 kev and 1 Gev of electron-anti- electron, and proton-anti-proton annihilation. This is not seen, so that means that at some time after the Big Bang, any matter and anti-matter managed to segregate itself ( No known way to do this UNLESS matter and anti-matter are affected by gravity in different ways), or that starting from time zero, there has always been an asymmetry in the mater/anti-matter abundance. We know that K mesons decay into more matter than anti-matter end particles, so nature doesn't really treat matter and anti-matter the same way even though these forms are produced in equal numbers during 'pair creation' events. In a previous question I also discussed this.\n\nAs to WHY this is so, so that we only see matter galaxies, we have to say that this is simply the way Nature is. Just as the speed of light is fixed at the particular value it has. No explanations seem possible or likely in the future.
1021193
No idea what you mean by your comment.....\n\nIn cosmology, dark matter refers to matter  of yet unknown composition, that does not emit or reflect enough light to be detected directly. But its presence may be inferred from gravitational effects on visible matter such as stars and galaxies. \n\nEvidence suggest that there is much more dark matter than visible matter. As it is non-interacting with light it must be of non-baryonic origin. It also must be stable, because it exists since the Big Bang, 14 billion years ago. The only candidate among the elementary particles we know already are the neutrinos. However there are theories like Supersymmetry that predict other particles, that would fit the known data.
611919
depends on who you ask, you could probably find all percentages because we are not capable of measuring black matter throughout the whole universe.
477879
Well, the one is matter and the other is energy.\n\n=====\n\nIn cosmology, dark matter refers to hypothetical matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation to be detected directly, but whose presence can be inferred from gravitational effects on visible matter such as stars and galaxies. The dark matter hypothesis aims to explain several anomalous astronomical observations, such as anomalies in the rotational speed of galaxies (the galaxy rotation problem). Estimates of the amount of matter present in galaxies, based on gravitational effects, consistently suggest that there is far more matter than is directly observable. The existence of dark matter would also resolve a number of inconsistencies in the Big Bang theory, and is crucial for structure formation.\n\nIf dark matter does exist, it has vastly more mass than the "visible" part of the universe [1]. Only about 4% of the total mass in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space, that probably cannot be thought of as ordinary particles. Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics. Its urgency is underlined by David B. Cline in a 2003 article in Scientific American, in which he writes: "The terms . . . 'dark matter' and 'dark energy,' serve mainly as expressions of our ignorance." [2]\n\n=====\n\nIn cosmology, dark energy is a hypothetical form of energy which permeates all of space and has strong negative pressure. According to the theory of relativity, the effect of such a negative pressure is qualitatively similar to a force acting in opposition to gravity at large scales. Invoking such an effect is currently the most popular method for explaining recent observations that the universe appears to be expanding at an accelerating rate, as well as accounting for a significant portion of the missing mass in the universe.\n\nTwo proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously, and quintessence, a dynamic field whose energy density can vary in time and space. Distinguishing between the alternatives requires high-precision measurements of the expansion of the universe to understand how the speed of the expansion changes over time. The rate of expansion is parameterized by the cosmological equation of state. Measuring the equation of state of dark energy is one of the biggest efforts in observational cosmology today.\n\nAdding a cosmological constant to the standard theory of cosmology (i.e. the FLRW metric) has led to a model for cosmology known as the Lambda-CDM model. This model agrees closely with established cosmological observations.\n\nThe term dark energy was coined by Michael Turner.\n\n=====\n\nZack,\n\nDark matter is not detectable.  It can't be seen with visible light, or astronomers would see fuzzy halos around galaxies.\n\nDark energy is a force that is causing the expansion of the Universe to accelerate.  Instead of holding the Universe together, dark energy is blowing it apart.
476348
Ask your friend if he knows about "dark matter". \n\nAlmost all the astronomers and most of the physiscists believe nowadays that only 4% of the Universe is made of "normal matter", that is made of neutrons, protons, electrons, photosn, etc (all the aprticles contained in the standard model of Particle Physics). The rest of the Universe is believed to be made of something whose nature is still not known, 26% of this "something" is called dark matter, the name is because it doesn't interact via electromagnetism, therefore, it can not produce, or be affected by light of any frecuency, it is then dark in the sense that no instrument based on light can detect it. The presence of dark matter however affects massive bodies by its gravitational influence, in the last decades its existence has been inferred in objects of very large size, like galaxies and cluster of galaxies, there are many indirect observations that sustain the existence of dark matter, the most stronger is probably the observed rotation curves fo galaxies, which doesn't match the expectations if we account only the visible ("normal") matter.\n\nCandidates for being the components of dark matter are beyond the Standard Model of Particles, going for supersymmetry to more exotic stuff like branes and extra dimmensions. It is a very interesting fields and many projects are currently being carried pout to discover it directly or know more about its nature indirectly.\n\nThe remaininf 70% of the Universe is even a bigger mistery, it is called "dark energy". It differs of dark amtter because contrary to it, it doesn't produce an atraction like the gravitational force, but a repulsion in the large scale Universe, so it is not the same as dark matter, and of course, not the same as normal matter, it is something else, there are theories that try to describe it, but we are still in the beggining of discovering what it is.
550266
It is expanding to the point of dark matter.  Then it will contract back into itself.  Then it was start all over again.  This is from the my interruption of the Kaballah.
1179663
In cosmology, dark matter refers to matter of yet unknown composition, that does not emit or reflect enough light to be detected directly. But its presence may be inferred from gravitational effects on visible matter such as stars and galaxies.\n\nEvidence suggest that there is much more dark matter than visible matter. As it is non-interacting with light it must be of non-baryonic origin. It also must be stable, because it exists since the Big Bang, 14 billion years ago. The only candidate among the elementary particles we know already are the neutrinos. However there are theories like Supersymmetry that predict other particles, that would fit the known data.
401680
The theory of dark matter has been developed to try and explain the observed characteristics of large-scale celestial objects, like galaxies. Mass (matter) causes gravity which in turn effects the shape and motions of things like spiral galaxies. However, the observed shape and motions of spiral galaxies can't be explained by the amount of matter known to be there. Some other kind of matter must be present, and that's called "dark matter."\n\nDon't confuse "dark matter" with "dark energy." The latter is another mysterious feature of the universe that is thought to be causing the expansion rate of the universe to be increasing.\n\nHere's the theorized percentages of dark matter, dark energy, and regular matter for the universe --\nDark matter.....23%\nDark energy.....73%\nRegular matter..4%\n\nYou could almost say that 97% of the universe appears to be missing :)
742823
Astonomers look at: (1) how fast galaxies are rotating, (2) how galaxies are moving relative to each other in clusters, and (3) how galaxies focus light from object beyond them ("gravitational lensing"). They then calculate how much mass there must be in those galaxies to explain those phenomena. Then they measure how much light is coming out of those galaxies and use that to estimate how much mass is in the galaxies. \n\nThe two techniques give very different numbers for the mass in the galaxies. The light measurement method yields a much smaller answer for the masses. Therefore, there is matter in the galaxies that is emitting little or no light.\n\nWhat dark matter is made of is a matter for speculation. Some of it may be neutrinos, which are abundant subatomic particles that were previous thought to have no mass but were recently determined to have a little mass. They are very, very numerous. Some may be "exotic" matter that we yet know nothing about.\n\nIt may be more mundane, however. We know that in our neighbor of the Milky Way, most of the starlight comes from just a handful of very bright stars, while most of the mass is in a large number of small, very dim stars.
380500
It's the matter in galaxies that provides enough gravitational force to prevent them from being flung apart by their angular momentum.  It's called dark because we can't see it
486232
The universe is theorized to contain dark energy and dark matter. There have been some confirmation of it's existence but really just speculation at this point. The idea of dark matter had been identified by Einstein but it wasn't till the discovery that the universe is accelerating it's expansion and contains up to 70% more matter that the idea of dark matter and energy became serious areas of study. If you mean a vacuum to mean absence of air it is a vacuum but within that "vacuum" there definitely is matter.
564206
are you asking about "dark matter"?  dark matter is an unknown kind of matter that only interacts with ordinary matter gravitationally.  about 85 percent of the matter in the universe is dark matter.  swiss astronomer fritz zwicky originated the term 'dark matter'.\n\nread these pages.  they will help.\nhttp://en.wikipedia.org/wiki/Dark_matter\nhttp://map.gsfc.nasa.gov/m_uni.html
696222
According to the world's best brains(Scientists) 80% of the universe is dark matter(read unknown). So it will take ages before we get any idea to your question.
840668
It's a pixel.\n\n1.I've never heard of a 'particulate'\n2. Is a method of coding an image into digital data.\n3. A method of printing, that involves striking pins against a ribbon coated with ink. Dot matrix printers are inefficient, noisy and expensive- but very, very fast.
295138
Suprise answer and correct! PLASMA\nPlasma is also the most common form of matter in the universe!
692417
Do calculations include black matter?