Quantum physics makes everyting a particle.  What kind of particle is dark matter?
204429
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.
208464
no one knows what existing in the earliest fractions of a second (i.e. nano seconds) - but in the first millisecond or so all the matter in the universe was quarks and gluons - this quickly cooled and these particles combined to form HARDONS (the subatomic particles we know today - protons, neutrons, etc.), but they existed in a plasma (like lightening)  After about 380,000 years the hardons cooled enough to form neutral atoms
228929
According to the standard model (which has proven correct MANY times) atoms are made up of neutrons and protons and are circled by electrons in their basic form. Neutrons and protons are both baryons (which are types of hadrons) and are composed of quarks. Quarks are fundamental particles (not composite) just like the electron. They are known as point particles as well.\n\nTheories are that these point particles are in fact strings (string theory) oscillating at different frequencies etc, but that is still disputed.
560427
You are surrounded by zero rest mass particles. They are called photons and they transmit the light from the screen to your eye. They transmit the electrostatic force that holds the atoms in your body together. They carry momentum but have no mass if at rest - in fact, they cannot exist at rest (though their phase velociy can be slowed to be near at rest).\n\nAny suitably modern and suitably advanced book on physics in any store in any country will give you the details, and the experimental verification that led to the conclusions. Try Eisberg and Resnick or Resnick and Halliday.\n\nZero rest mass particles are also affected by gravity, and this has also been measured using the mossbauer effect.\n\nThe zero rest mass particles in nature are those that carry the interactions between quarks and leptons.\n\nContrary to what is said elsewhere here, a charged particle cannot have zero mass because charge is a property of quarks, all of which have mass.\n\nSee ref below for more.
573877
A photon is a quantum of the vibrational energy of the space grid (as in the image above). At any one point on the wave, photons are produced out of the zero-point and then oppositely, photon holes are produced. Hence, it must be the case that these oscillations up and down come in discrete steps--or quanta.\n\n \n\nWhen a particle from the quantum vacuum acquires energy from a charged particle of matter, it may expand from the addition of this excitation energy to become an ordinary photon. Energy, therefore, expands the size of a virtual photon in ground state.\n\n \n\nA virtual photon, thus, is a "collapsed" short-range quantum that becomes an ordinary photon when given energy from an excited charged particle. Hence, the primary reason that we do not observe the photons that exist in the quantum vacuum, is because the quanta of space-time that compose the vacuum have a very minute amount of energy within them and are, therefore, too small to be observed directly. However, such vacuum quanta may become observable and measurable as ordinary photons after emission.\n\n \n\nWhen actualization takes place, we may measure photons and photonic energy hitting a measuring device.  But, while in-flight, we may not speak about photons at all, because technically speaking they are not photons.  So, when Planck's equation says that energy comes in lumps E = hf, this only refers to a state of an EM wave after an actualization or measurement has happened.  Prior to this we have only Kant's noumenal "wave" condition.  \n\nphotons must have higher frequencies, by exactly one hertz, than the expected difference of the energy levels of the electrons from which they received energy. Additionally, photon wavelengths must include a very long 3 x 10^8 meters to be added to all emitted wave fronts
221514
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.
471529
Particle theory of matter suggests that matter is made of tiny pieces with much space. One support for the idea is when they learned to shoot   particles, and most of them went right through, very few hit a nucleus. They were using a sheet of gold.
94377
The clue is in your question:  "We find."  How do you know what becomes of antiparticles we don't find?
554122
The basic building block of matter, and the foundation for modern theories of matter and the universe. Quarks combine with gluons to make the protons and neutrons that make up every atom in the universe.
588262
WIMPS are "Weakly Interacting Massive Particles", which are hypothetical particles that have been invoked to solve the "dark matter" problem.  (Astronomical observations of things like the rotational speed of galaxies, and the interactions of galaxies in clusters can be explained if there is some form of matter, called "dark matter", that does not absorb or emit electromagnetic radiation, and thus cannot be detected by normal astronomical observations).\n\nWIMPS would only interact with other particles (and each other) via the weak and gravitational forces.  They would therefore be very hard to detect.  Because no one has yet detected them, and there are are not predicted by the "standard model" of particle physics, they remain simply an interesting conjecture.\n\nWIMPS are supposed to have large masses, and clumps of them could act as "gravitational nuclei" for the formation of galaxies in the early universe.  I do not know of any other connection between WIMPS and the inflationary scenario for the early universe.\n\nThe bubble theory of the universe is a variant on the currently favored inflationary theory for the early universe.  In this theory, instead of a single point expanding at a single time to form a single universe (ours) that constitutes all of physical reality, different portions of physical reality "decay" to form independent universes at differing times.  Physical reality would therefore correspond to a "foam" of independent universes, each of which is completely isolated from one another.\n\nI've never heard of the "hyperdimensional theory of the universe".
186506
Quantum physics is a branch of science that deals with discrete, indivisible units of energy called quanta to relate that movie to it, well, it could be used as a inside joke, if you touch my back , well you in heat, if you get my point.
487124
Eather is debunked idea proven to not exist experimentally. Michelson-Morley experiment showed eather can't exists. I think dark matter is really something else. But it comes into play some role in Einstein's struggle to deal with expanding universe which he originally believed was static and unchanging.\n\n\nhttp://en.wikipedia.org/wiki/Michelson-Morley_experiment
67724
Most physicists (like Feynman) will tell you it's definitely a particle.  I think they're full of crap, and it's a wave.  The fact that it can only be absorbed and emited in discrete packets doesn't necessarily mean that it really travels as a particle, and the notion of a particle flies in the face of the double-slit one-photon experiment.
193118
It is completely unknown, since we cannot measure it and have no examples-we dont even have any proper theories, since there is also dark energy, and we dont know which of the effects we observe are due to dark matter and which due to dark matter.  We do suspect that dark matter generates gravity, and perhaps generates and anti-gravitational force (though normal mass may also do this at large enough distance)  We also know that it does not seem to block any kind of electromagnetic wave, nor does it generate any that can be detected, so it isnt just something like dust clouds or large planets without stars.
654945
In fact, there is a great deal of evidence showing it is not. What little we know of the dark matter and energy is that they are not composed of baryons. But anti-protons *are* bosons. There are some candidates for the dark matter (axions are a good bet) but anti-matter in the usual sense is ruled out by observation.
531831
The dark matter hasn't gone anywhere.  The problem is we can't see it directly because it doesn't or reflect any light (hence the name!).  It is defninitely there, but we don't know what form it takes - is it normal matter that just happens to be really really dark (dark dust, very faint brown dwarfs, isolated black holes)?  Or is it some form of weird, exotic matter that we have yet to discover (I know that sounds far-fetched on the surface, but it actually isn't).\n\nWe suspect that dark matter exists for various reasons.  One is by observing how spiral galaxies rotate.  By watching any object orbit around another (like our Sun or other stars orbiting around the center of our galaxy) we can calculate the mass of the thing being orbitted.  But with all spiral galaxies (and others, too) the mass we calculate is far greater than the mass of all the stuff (stars, gas, dust) that we can see - therefore there must be stuff in our galaxy that we can't see, but that still has a significant gravitational effect.\n\nWe also see galaxies orbiting each other.  Here again, but watching them we can calculate how much mass there is, since mass determines gravity.  If we only had the mass of the visible stuff inside and outside the galaxies, those galaxy clusters should break apart - the gravitational force from all the visible stuff isn't strong enough to hold those clusters together.  But those clusters do stay together, so there must be more dark matter there between the galaxies.\n\nNow you may just be asking yourself "maybe gravity doesn't work the same on the galactic scale as it does here on Earth", which is a question scientists have asked, as well.  But recent evidence suggests that that is not the case - that we really do need dark matter to explain our observations.\n\nIt gets even weirder - we now think there's something called "dark energy" that is causing our Universe to epand at a faster rate, instead of being slowed down by gravity the way we used to expect.\n\nThere are quite a few good books about this stuff written for laymen - just puruse your local book store in the science section.  And if it all seems too confusing, don't worry - it's confusing to the scientists, too!  As I tell my students, if it all seems to make sense, you're not paying attention!
542777
Photons and gluons are massless particles.  Several other massless particles have been hypothesized but not confirmed.\n\nElementary particles have a probabilistically distributed location that engenders wavelength. The wavelength of a particle is inversely proportional to its energy.\n\nParticles with mass can only approach the speed of light.  Particles without mass can only propagate at the speed of light.