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Matter to energy

  1. Oct 13, 2004 #1
    How exactly does matter turn into energy and what causes it?
     
  2. jcsd
  3. Oct 14, 2004 #2

    Mk

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    How do you remember how many z's you have in your username if your browser doesn't remember it?
     
  4. Oct 14, 2004 #3
    Hahaha!

    I believe it has something to do with the two parts of the atoms ripped apart weighting less than the original atom. Of course that doesn't answer your question, but you can look into potential energy and its relation to mass somewhere, I'm sure.
     
  5. Oct 14, 2004 #4
    there are exactly eleven z's
     
  6. Oct 15, 2004 #5

    Mk

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    Maybe it has to do with where and how many gluons are released in your example? How does the higgs field fit into this?

    Heat is energy, and it is obvious on how the matter transfers its energy in this example.
     
  7. Oct 17, 2004 #6
    matter and energy are so interrelated that it is difficult to distinguish one from the other. you see energy is somehow connected with motion of mass. (e=m*v^2)but as yet i have not heard about such things as pure energy or pure mass. as you know even light which consists of massless(rest mass=0) photons interacts with gravity the same as a tennis ball does. the best way to understand energy and mass perhaps is as if they are two sides of the same coin. so matter is energy and energy is matter. but i'm not an expert, perhaps others can give you a better answer fiZZZZZZZZZZZy.(why 11 i wonder!)
     
  8. Oct 18, 2004 #7

    Mk

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    And, all mass is interlocked with every force, gravity, EM, weak and strong. All mass has gravity, the atoms sticks together because of the EM force, strong, to keep the atoms together. The weak force, involved in the decay of the mass. Exotic matter, anti-matter and matter are all in an intricate system with these forces. Its like a spiderweb, the spider, energy decided to make the spiderweb silk, the matter. The higgs gauge boson, is belived to be the final gauge boson, to more complete the standard model. The higgs field is supposed to be the bosonic field that makes energy into matters. http://newsimg.bbc.co.uk/media/images/39882000/gif/_39882466_standard_model2_416.gif :smile:
     
    Last edited: Oct 18, 2004
  9. Oct 18, 2004 #8

    reilly

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    Good question, hard question. In effect, quantum theory applied to nucleii and particles is based on the idea of transformations -- protons can make a transition to proton+photon states, neutrons --> protons + pi - mesons, etc. Why ? Nature has shown us the way, and physics honors basic phenomena. We can describe, but a fundamental explanation is not around yet. Conservation laws preclude some transformations, but radiation, beta decay, pair production, photoproduction of mesons, all can occur, provided energy, momentum, angular momentum, charge, ... are conserved. Again, energy<-->matter is built directly into QFT. transformations happen, but who really knows why?
    Regards,
    Reilly Atkinson
     
  10. Oct 19, 2004 #9

    Mk

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    How many photons come out per proton transition?
     
  11. Oct 22, 2004 #10
    when matter and antimatter react they create pure energy
     
  12. Oct 23, 2004 #11

    Mk

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    Yes, some guy with a last name starting with "D," found that Einstein's equation "E=mc2" also works as "E=±mc2". Anti-matter fission reactions result in the same amount of energy as matter fission reactions. Matter is a highly concentrated form of energy.
     
    Last edited: Oct 23, 2004
  13. Nov 2, 2004 #12
    i am so impressed with you guys.
    i am so poor in Physics so i am so glad to see you all.
    is there anyone who have interest in molecular biology?
    may i know some concepts of physics that deals with biology?
     
  14. Nov 4, 2004 #13

    Garth

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    Hi Kaungkyaw, welcome to these Forums. You may find something about biology and molecular biology on the "Other Sciences - biology" Forum.
    Happy hunting!

    Garth
     
  15. Nov 5, 2004 #14
    Using this opportunity to renew the thread. . .

    what I find fascinating about the matter/energy "conversion" thing is that, really, no energy is ever lost, and neither is mass/matter. When we talk about matter being lost, we're really talking about mass, because that is what we measure decreasing in after, say, nuclear fission. But there's a funny little fact ignored by a lot of,say, popular science writers. Mass is never really lost in fission, it's just distributed over a wider system (you could say it passes from rest mass to relativistic mass, but I don't like those concepts very much; they're rather artificial). If you play around with the force equation of special relativity (f=d(mv)/dt) you can quickly derive the result that, if you put a certain energy KE into a particle, that particle will experience a relativistic mass increase of KE/c^2 - which, of course, corresponds exactly to the mass "lost" by, say, an atom in the fission process (since the KE of fission fragments is equal to delta(m)c^2, the observed change in mass times the speed of light squared). The reason why we observe mass decreases is that we measure the mass of fission fragments after we've slowed them down - and then they've imparted their mass (energy) to particles all around them already, which we're not accounting for. So, as a result, only rest mass is "lost", but effectively both mass and energy have been conserved.

    Of course, these are rather artificial concepts here, since we're in the world of photons and other things for which it is hard to define such a quantity as mass, and we must rely on momentum instead. And it's also a question whether we want to accept relativistic mass as "legal" or not in mass conservation. But the fact remains that, at least in a sense, "mass conversion" is a fiction.

    I'd appreciate any comments on the validity of this view of mass conversion, since this is just something I came up with by tinkering with relativity, based on bits and pieces I'd read here and there. I'm still pretty far from a good understanding of what's really going on.
     
  16. Nov 6, 2004 #15
    Perhaps you can define exactly what you mean by 'mass'? There are reactions - particle-antiparticle annihilation - in which two particles with mass (either 'rest' or 'relativistic', it doesn't matter) are turned into photons, which are massless by any standard. How can mass be "effectively conserved" in this case?
    Rest mass is defined as the invariant 4-length of the energy-momentum four-vector. It is the best and most common definition of mass, since it is the same in all frames of reference. Relativistic mass is frame-dependent and equals the particle's rest mass times its relativistic gamma factor. As discussed, neither is conserved in interactions.
     
  17. Nov 6, 2004 #16
    Yeah, caught me there, this is where my disclaimer at the end of the last post comes in - I was talking more about the supposed mass conversion occurring in fission (when fission fragments leave with a KE equal to their change in rest mass, and this KE corresponds to an increase in relativistic mass equal to their decrease in rest mass) than about photon interaction. Fission is often advertised (including in college chem classes I've been in) as an instance of mass loss, when, in a very substantial sense, mass hasn't really been lost (if you're willing to accept relativistic mass as real mass - which i'll comment on further down below).

    Of course, since photons can hardly be continuously decelerated in a collision like "normal" particles, we can't define a mass for them as in the context of Newton's 2nd law. It's very interesting, though, that, for a photon created from a mass m, the momentum is still linearly dependent on m (p=mc). You are right that it's incorrect to claim this conserves mass even "effectively" if we use a consistent definition of mass - I should've made it clearer which cases of "mass loss" I was trying to debunk - but it is true that, even in pair production (and annihilation), there is a lot to photon behavior that can be described by use of analogy to mass (the quantized velocity of light is probably the main effect of making photon mass a not fully viable concept, and this, of course, is where the sidestep of introducing momentum comes in). (Now comes a disclaimer part - everything after this is speculation; I've not yet studied the relevant areas in sufficient detail, I'm just talking about what I find fascinating without pretending to have confirmed any of this yet or even to have seriously investigated if others have already) Even so, I suspect there's a very strong connection between the momenta of waves and the masses of "particles"; in particular, I suspect that what we observe as the masses of objects, with their capability for smooth acceleration and so forth, are in fact the compound effects of momenta of some kind of waves that make up what we think of as matter. :biggrin: This is the Duarh theory of everything, v. alpha 0.1, still waiting for me to even take a serious quantum class.

    This connects to:
    I might be quite missing the point here (quite honest, I'm writing this with curiosity, not trying to state the way things are or anything), but it seems to me that a "rest mass" is a concept only applicable with any kind of logic to idealized systems of point particles. Real world objects - and not only teapots and bullets, but also molecules and atoms - don't ever stand still; they're mechanisms with inner workings that (by m=E/c^2) change in mass upon any interaction with their surrounding environs. So, if we take into account the fact that any observation/interaction is bound to deliver energy to a system (and, connectedly, if we take note of the uncertainty principle), how can there ever be a definite rest mass of a system other than for a (nonexistent, as far as I understand) point mass and how can one hope to ever measure such a mass? Given that, I don't see how rest mass is the "best" definition of mass; yes, it's handy since it makes the math way easier, but it seems to me it's an idealization to a dangerously large extent.

    Just to acknowledge sources, I recall getting the original idea for this here, a significantly more reputable source than my own self. I think I grabbed it and ran w/o ever reading all the way through, so I'm not sure how much what I said diverges from/coincides with what's in this document:

    http://www.teleles.nl/pdf/total_artikel.pdf
     
  18. Nov 6, 2004 #17
    That's a long post, and I'm pressed for time, so forgive me if I don't discuss things in sufficient depth - there are plenty around to pick up the slack.
    What makes one form of mass any more 'real' than others? Rest mass is more useful because it does not depend on the frame of reference you measure things in. (Keep in mind that SR says there are no preferred frames.) The rest mass is truly associated with the particle: all electrons have the same rest mass, whereas their relativistic mass would vary depending on our arbitrary determination of their speeds. Nature is quite clear on this: it is the rest mass that is the same for all electrons, and hence can be said to be an intrinsic property of such.
    I don't know how you arrive at this result. How is a photon "created" from a mass m? No process exists whose only effect is to convert a mass m into a SINGLE photon of energy mc^2. Such a process violates energy-momentum conservation. A mass m can be converted into multiple photons. The sum of the magnitudes of their momenta is indeed mc, but I fail to see the point.
    I do not want to explain all the intricacies of this. Once you get around to that serious QM class, this will hopefully be made clear.
    Let's keep QM out of this for now. Any system of particles has a rest frame, in which its rest mass can be defined. All you need to do is sum up all the momenta of its components in an arbitrary frame. This will give you some (momentum) vector p. At this point, it can be shown that there is a unique positive scalar m and a velocity v such that p=mv and the system has zero total momentum as measured in the frame moving at v with respect to the original frame. Hence you can define a rest frame and a rest mass for any system, regardless of its internal complexities. The way the internal energies, temperatures / random motion, potential energies etc contribute to this mass is beside the point and can all be accounted for.
     
  19. Nov 7, 2004 #18
    I guess what I was thinking about was that, even though we may assign masses to macroscopic bodies at any point in time, their internal energy content is constantly changing - which, of course, also means that they're no longer the "same object" as before - so even when we call an object's mass a rest mass, we're still talking about a "relativistic" mass in the sense that it depends, for instance, on the energy stored in the bonds of its molecules, which changes constantly because no real-life object is a closed system. But I guess that's not as meaningful as I thought - thanks for that net momentum explanation at the bottom of your post, btw, it clarified a lot - since I could claim in the same way there's no use talking about the energy of a system because it's changing all the time. Point being, rest mass isn't strictly defined and unchanging for any object because no object is strictly defined and unchanging, but that doesn't necessarily really limit the usefulness of rest mass as a theoretical concept.

    Yes, I was thinking about _pair_ production, should've been clear about that. I just find it very interesting that the, say, ability of photons to
    nudge things around is linearly related to the ability of the particle that created them to do so. It's another example of conservation in nature, which I always find fascinating.

    Hopefully. I should probably be studying towards that end now instead of posting my hypothesizing in physics forums; would be much more productive. Ah well. Thanks for the responses.

    (:biggrin: hmm, but I still feel that the way people talk about mass being lost all the time is a bit misleading,even though I understand why it might happen if the notion of relativistic mass has been abandoned altogether in modern usage.)
     
  20. Nov 16, 2004 #19
    hmnn if you want to turn matter into engery, you would have to accelerate it by the speed of light squared. or about 90000000000000000 meters per second
     
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