Freethinker Posted June 18, 2004 Report Posted June 18, 2004 Originally posted by: lindagarretteThis leads to the question what is mass? Is it just a mathematical concept?My guess would be that we don't KNOW enough about matter/ mass to "understand" what it is beyond the mathematical models.The smallest measurable mass has to be a quark.Do Strings have mass? If they have "shape" and "motion", they must have mass?
Uncle Martin Posted June 18, 2004 Report Posted June 18, 2004 Considering that mass can become energy and energy become mass, I wonder where is the line between them? String?, Quark? Some as yet unknown ultra high energy wave? We do have much to learn yet.
Freethinker Posted June 18, 2004 Report Posted June 18, 2004 Originally posted by: Uncle MartinConsidering that mass can become energy and energy become mass, I wonder where is the line between them? String?, Quark? Some as yet unknown ultra high energy wave? We do have much to learn yet.E=MC^2 Thus the "line" would be velocity? The difference between mass and energy is motion?
Uncle Martin Posted June 18, 2004 Report Posted June 18, 2004 I think we're ready to publish our theory of everything. The only unsolved issue is whos name appears on the paper first?
Freethinker Posted June 18, 2004 Report Posted June 18, 2004 You can have top billing, I want the movie rights!
lindagarrette Posted June 19, 2004 Report Posted June 19, 2004 Originally posted by: FreethinkerOriginally posted by: lindagarrette This leads to the question what is mass? Is it just a mathematical concept? My guess would be that we don't KNOW enough about matter/ mass to "understand" what it is beyond the mathematical models. The smallest measurable mass has to be a quark. Do Strings have mass? If they have "shape" and "motion", they must have mass? It's possible that all particles at rest have no mass. I looked up Higgs boson. Very interesting. There's really nothing at all but energy.
TeleMad Posted June 19, 2004 Report Posted June 19, 2004 lindagarrette: It's possible that all particles at rest have no mass. I looked up Higgs boson. Very interesting. There's really nothing at all but energy. I'm a bit rusty so this getting beyond my current grasp, but I think you might have misconstrued what you read. In particle physics mass is usually given as energy, not kilograms. For example, although an electron has a mass of 9.11 x 10^-31 kg, in particle physics an electron's rest mass - its rest energy - is usually listed as 0.511 MeV. So an electron at rest does have mass, whether it is expressed in terms of kilograms or electron volts. Even if the above is correct, that still leaves open the question of whether an electron itself has mass or if it has mass only because of Higgs bosons.
lindagarrette Posted June 19, 2004 Report Posted June 19, 2004 But according to the theoretical work by British physicist Peter Higgs and others in the 1960s, the giver of mass is a neutral particle with zero spin that we call the Higgs boson. All the fundamental constituents of particles (or MeVs--quarks and leptons--get their masses by interacting with the Higgs boson. But the Higgs boson remains hypothetical; it has not been observed. That is why particle physicists often use the search for the Higgs boson as a shorthand for the campaign to learn the agent that hides electroweak symmetry and endows other particles with mass. -- from Scientific American Ask the Physicist. And would strings in M-theory have mass? And what is volume? The distance between masses or something to do with MeVs?
TeleMad Posted June 19, 2004 Report Posted June 19, 2004 lindagarrette: And would strings in M-theory have mass? Not sure. Skimming a bit through a couple books, I found this, but I am not sure if it helps. "String theory proclaims, for instance, that the observed particle properties, the data summarized in Tables 1.1 and 1.2 [which list particle masses along with other properties], are a reflection of the various ways in which a string can vibrate. Just as the strings on a violin or on a piano have resonant frequencies at which they prefer to vibrate - patterns that our ears sense as various musical notes and their higher harmonics - the same same hold true ofr the loops in string theory. But we will that, rather than producing musical notes, each of the preferred patterns of vibration of a string in string theory appears as a particle whose mass and force charges are determined by the string's oscillatory pattern. The electron is a string vibrating one way, the up-quark is a string vibrating another way, and so on." (The Elegant Universe: Superstrings, Hidden Dimmensions, and the Quest for the Ultimate Theory, Brian Greene, Vintage Books, 1999, p15) lindagarrette: And what is volume? The distance between masses or something to do with MeVs? Not sure I understand. Volume is the amount of three-dimensional space something occupies; at least that is the usual definition. Are you looking for a deeper meaning?
Bo Posted June 21, 2004 Report Posted June 21, 2004 This leads to the question what is mass? Is it just a mathematical concept?Well mass is a lot of things actually... First of all: Mass is a form of energy. An intrisic property of a particle in which energy is kept. Think for example of a fly-wheel: by rotating it (and asuming a vacuum in which it will keep rotating without energy loss) we can put energy there. The fact that a particle has mass has then al kinds of physical propeties (it gives rise to a gravitational attraction). the interesting question is: where does mass come from? Unfortunatly there is no easy answer to this. The current theory state that in principle all particles are massless, but there is a particle called the higgs particle that gives the fields their mass. (the proof for this is purely mathematical; you can see the higgs particle as the person turning our fly-wheel above) The higgs particle will probably be detected in the coming years at the LHC in CERN (or it will not be detected, proving that this theory is wrong...)Do Strings have mass? If they have "shape" and "motion", they must have mass?The fact that particles have shape or motion has nothing to do with mass. e.g. the photon is massless, however it has shape (it's a(n electromagnetic wave)) and motion (it travels at the speed of light). But then again: Yes strings CAN have mass. As you might know: in string theory different particles are represented by different excitations or harmonics of the string (see for example http://hyperphysics.phy-astr.gsu.edu/hbase/waves/string.html#c3). In most string theorys the ground state is a so called tachyon: a particle with negative mass (people are still working on how to interpret these); the first excited state is massless; and the higher excitations are massive particles. I dont really know how the connection with the higgs particle should be made here... [but it's a very intersting question; i'll try to find it somewhere...] And what is volume? The distance between masses or something to do with MeVs?Volume is a propertie of the structure of spacetime. And since spacetime is also present if you remove all the particles; volume has nothing to do with that. I think we're ready to publish our theory of everything. The only unsolved issue is whos name appears on the paper first?Unfortunatly i think we're close to stating 'this might be the theory of everything' But before we can say "This is it" still a lot has to be done, both theoraticly as well as experimentally (there is no real experimental proof for strings, branes supersymmetry or anything like that).You all say that anti particles dont exist and yet if Cern are producing them they clearly can exist unless you dont consider France to be part of our universe.There is i think no doubt that antimatter exists; but i must correct you here: CERN is in switzerland! Bo
Recommended Posts