what is the neutrino rest mass?
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This is a question that is being actively researched right now. It is related to the issue of 'neutrino oscillations' where neutrinos spontaneously convert from one type to another. These oscillations have been detected and that means at least one neutrino has a non-zero mass, but more specifics are still to be discovered.
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1) The photon is a force carrier of the electromagnetic force, the neutrino is not a carrier but feels the weak force.\n\n2) The neutrino has an antiparticle, the photon does not.\n\n3) The neutrino's interaction rate with matter is proportional to its energy, the photon's rate is dominated by resonances.\n\n4) The neutrino is the main energy carrier at supernova explosions, when matter is opaque to photons.\n\n5) The photon is massless, while the neutrino has a small but finite mass (follows from the discovery of neutrino oscillations)\n\n6) The neutrino comes in three flavours (electron, muon, tau neutrino), the photon in only one.\n\n7) The neutrino has spin 1/2, the photon spin 1.\n\n8) Human beings can detect photons, but not neutrinos (at least not without a huge apparatus)
442120
Whoa, man, why do you want to know? Do you know how suspicious you look after 9/11? \n\nthe critical mass for U-235 is 15 kilograms.
374421
mass=density over volume\n\n=)
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First of all neutrinos are not massless.\n\nSecondly even if they were massless they could still have energy because they have a wavelength.\n\nThird, neutrinos do exist despite the claims of those who still believe in the long discredited autodynamics theory.
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http://en.wikipedia.org/wiki/Neutrinos
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The correct answer is that no one knows.  We don't even know what most of the universe is made of (right now it's being called dark matter, because all we know about it is that we can't see it).\n\nIf I had to make a bet, I would go with total energy equals zero.  \n\nThere is a lot of matter in the universe, as everyone is saying, and that makes for a lot of mass energy.  But, the flip side is that there is a lot of mass in the universe, and that makes for a lot of negative gravitational potential energy.  It is possible they cancel.
32912
b) has the smallest mass
791190
Only if E=MC^2\n\n... it follows that if there is a change in the rest-energy of a body, there must be a corresponding change in its rest-mass. For example, if a body is heated, and thereby absorbs a small amount of energy ΔE (as measured in the frame of reference in which the body is at rest), its rest-mass will increase by a very small amount equal to ΔE/c2. This increase is tiny because of the high numerical value of the speed of light. Indeed, for mid-sized objects, such an increase in mass would be too small to measure with even the most accurate balance. For example, if a 1 kg block of gold is heated so that its temperature increases by 10 °C, then, ceteris paribus, its mass would increase by as much as 1.4 × 10-14 kg; a cube of gold of this additional tiny mass would have sides smaller than one one-thousandths of a millimeter. Similarly, if a body emits an amount of energy ΔE, say in the form of light or heat, its rest-mass will decrease by a tiny amount ΔE/c2. In both cases, the important and novel claim made by SR is that the inertial mass of a body can change depending on whether it absorbs or emits energy. This is true, of course, not just for isolated mid-sized objects but for any physical system.
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.
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As Mez says, you can't travel at the speed of light and measure any passage of time at all.  Clocks stand still at light speed.\n\nUntil recently, we did not know if neutrinos had rest mass or not.  It was thought they might be massless and travel at the speed of light.  However, observations conducted by neutrino observatories found that some solar neutrinos were switching between neutrino flavors during their flight from sol to the detectors.  This showed they must therefore have an internal clock running (or their initial state would be frozen), confirming they have a (small) rest mass and therefore travel at sub-light speeds.
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yes\n\nlet:\nMo = resting mass\nc = speed of light\nv = current speed\nsqrt = square root\n\nThen M (moving mass) = Mo/sqrt(1-v^2/c^2) = L*Mo\n\nL is the Lorentz Factor = 1/sqrt(1-v^2/c^2)\n\nM, the moving mass is called the relativistic mass\n\nNote the energy to move is E = L*Mo*c^2 so as v approaches c the Lorentz factor goes to infinity and so does E. Most people write E = Mc^2 but this M is equal to L*Mo\n\nAlso note that when you move (even at slow speeds) your mass goes up just a small fraction.\n\nThis leads us to the reusable nuclear bomb. Assume you make a nuclear bomb with not enough material (less than critcal mass), you put this bomb on a very fast plane. For the people on the plane the mass does not change so it never has critical mass, however, to observer on the ground (who sees the plane moving) the mass increases and goes over critical mass. So those people on the plane when they detonate the bomb it does not complete the reaction but to those on the ground it does. Think about the possibility...
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The existence of neutrinos was postulated to explain what was \nobserved when a nucleus undergoes beta decay via electron emission (a neutron \nin the nucleus changes into a proton, and the nucleus emits an electron).  \nObservation seemed to indicate that, in general, neither momentum nor total \nenergy was conserved in such a reaction.  This was, understandably, \ndisturbing.  In 1931 the physicist Pauli proposed that another, unseen \nparticle was also being emitted in the reaction, accounting for the "missing" \nmomentum and mass-energy.  Fermi named this particle neutrino" meaning "little \nneutral one".  The name reflected the assumption that it had no electric \ncharge (so that the law of charge conservation would remain intact); \nadditionally, it was postulated to have zero spin (keeping the law of \nconservation of angular momentum) and to interact only weakly with matter (to \nexplain why it was virtually undetectable). Eventually the neutrino was \ndetected, in the early 1950's, through nuclear reactors (which produce huge \nnumbers of neutrinos).  Currently it is believed that there are three kinds of \nneutrinos (plus their antiparticles, making a total of six) -- the electron-\nneutrino, the muon-neutrino, and the tau-neutrino.  Neutrinos are considered \nto be the force-carriers associated with the fundamental force called the weak \nforce. The weak force is very important -- it contributes to the production of \nelements of higher atomic number, without which life as we know it would be \nimpossible.
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The neutrino is an elementary particle. It has half-integer spin and is therefore a fermion. The neutrinos observed so far all have left-handed helicity (i.e., only one of the two possible spin states is realized). The masses of the neutrinos are very small compared to most other particles, although recent experiments (see Super-Kamiokande, Sudbury Neutrino Observatory and KamLAND) are widely believed to have shown them to be nonzero. As yet, no experiment has been able to directly measure neutrino mass. Since it is an electrically neutral lepton, the neutrino interacts neither by way of the strong nor the electromagnetic force, but only through the weak force and gravitation.\n\nBecause the cross section in weak nuclear interactions is very small, neutrinos can pass through matter almost unhindered. For typical neutrinos produced in the sun (energy of a few MeV), it would take approximately one light year (~1016m) of lead to block half of them. Detection of neutrinos can therefore be challenging, requiring large detection volumes or high intensity man-made neutrino beams.\n\nThe neutrino was first postulated in 1931 by Wolfgang Pauli to explain the energy spectrum of beta decays, the decay of a neutron into a proton and an electron. Pauli theorized that an undetected particle was carrying away the observed difference between the energy and angular momentum of the initial and final particles. Because of their "ghostly" properties, the first experimental detection of neutrinos had to wait until about 25 years after they were first discussed. In 1956 Clyde Cowan, Frederick Reines, F. B. Harrison, H. W. Kruse, and A. D. McGuire published the article "Detection of the Free Neutrino: a Confirmation" in Science (see neutrino experiment), a result that was rewarded with the 1995 Nobel Prize.\n\nThe name neutrino was coined by Enrico Fermi - who developed the first theory describing neutrino interactions - as a word play on neutrone, the Italian name of the neutron. (Neutrone in Italian means big and neutral, and neutrino means small and neutral.)\n\nThe Standard Model of particle physics assumes that neutrinos are massless.\n\nn particle physics, an elementary particle is a particle of which other, larger particles are composed. For example, atoms are made up of smaller particles known as electrons, protons, and neutrons. The proton and neutron, in turn, are composed of more elementary particles known as quarks. One of the outstanding problems of particle physics is to find the most elementary particles - or the so-called fundamental particles - which make up all the other particles found in Nature, and are not themselves made up of smaller particles.\n\n\nBy the way can you give me some links related to CHAOS THEORY? E-mail me please!\n\nPlease check the following links for more info.
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Europa\n\nIo: Diameter: 3643 kilometres. Mass: 8.93×10^22 kilograms \nEuropa: Diameter: 3122 kilometres. Mass: 4.8×10^22 kilograms \nGanymede: Diameter: 5262 kilometres. Mass: 1.48×10^23 kilograms \nCallisto: Diameter: 4821 kilometres. Mass: 1.08×10^23 kilograms
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Oh boy oh boy oh boy.  Let me tell you.  I'm so excited... I actually work with neutrinos.\n\nOkay.  So there are three different types of neutrinos, corresponding to the three different types, or "flavors" of matter, and they get heavier as you go along: there are electron neutrinos, mu neutrinos, and tau neutrinos, getting heavier from left to right.  Also, for each of these neutrinos, there is an anti-neutrino, for a total of six types of neutrinos.  THE THING IS that some physicists postulate that a neutrino and an anti-neutrino are the same thing, that each neutrino is its very own anti-neutrino.  The jury's still out.\n\nNeutrinos are the smallest particle (for a while, people didn't even think they had mass.  But they do).  To add to their mystery, they don't really interact with matter.  In fact, one can't directly measure a neutrino - it's impossible, because it won't interact with whatever material your detector is made out of.  Rather, physicists study neutrinos by studying the photons and other goodies created when neutrinos randomly decay.\n\nThe most common source of neutrinos on our good ol' planet Earth is our friend the Sun.  Nobody notices it because the neutrinos don't really do anything, but we're bathed in solar neutrinos all the time.
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There are 3 types of electrons and three types of neutrinos, so not sure which you want, I suppose the most stable form. Since buddy already gave you proton, electron and neutron, I'll just add to that.\n\nProton mass: 0.938 GeV/(c^2)\nNeutron mass: 0.940 GeV/(c^2)\nElectron mass: 0.000511 GeV/(c^2)\nNeutrino mass: 1 x 10^(-8) GeV/(c^2)\nPhoton mass: 0 GeV/(c^2)\nTotal mass: 1.879 GeV/(c^2)\n\nA GeV/(c^2) is an energy unit defined as the amount of potential gained when an electron moves through a potential of one billion volts, it is given per speed of light squared which you may recognize from the energy/mass relation E = m(c^2). \n\n*Edit*\nI left a crucial part out of the calculation. Here it is again proper:\n1 GeV = 10^9 eV\n1 ev = 1.602176 x 10^-19 kg*m^2/s^2\nc = 299792458 m/s\nYou can use E = mc^2 to solve for m in kg OR to get mass in kg you can also multiply the amount in GeV by 1.783 x 10^-27. Sorry for the mistake earlier. Now if you test my answers with ThePhysicists' answers they will be the same.