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redhedkangaro
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Are the stings in string theory, considered to be matter?
Are the fundamental particles of the universe cnsidered to be matter?
Are the fundamental particles of the universe cnsidered to be matter?
redhedkangaro said:So matter and energy are diiferent or are they essentially one?
malawi_glenn said:I don't think one should use the word "matter" since it is ambiguous - it depends on who you ask what matter is. A particle physicist (like me) would call photons (light) matter, but maybe not a atomic physicist - it is not a fundamental concept, it has no clear definition.
Mass and energy are the same thing, we had long such discussions like a month ago, would be good if you could find those old threads by using the "Search" function. We also had a discussion on what "pure energy" is, if you had the intentions to ask about it too.
enotstrebor said:Matter has mass (see http://en.wikipedia.org/wiki/Matter" ), but maybe it is different in your circle of friends.
However, energy and mass are not the same thing!
The photon has energy but no mass. A massed particle has energy but has massed properties which are different than photon properties. Mass can travel at any velocity less than "c" and requires energy to change its velocity, while the photon only wants to travel at "c''.
As massed energy and photon energy behave differently, energy and mass can not be the same thing.
E=mc^2 says that there is a relationship between the two not that they are the same.
Are the stings in string theory, considered to be matter?
Are the fundamental particles of the universe cnsidered to be matter?
enotstrebor said:Matter has mass (see http://en.wikipedia.org/wiki/Matter" ), but maybe it is different in your circle of friends.
However, energy and mass are not the same thing!
The photon has energy but no mass. A massed particle has energy but has massed properties which are different than photon properties. Mass can travel at any velocity less than "c" and requires energy to change its velocity, while the photon only wants to travel at "c''.
As massed energy and photon energy behave differently, energy and mass can not be the same thing.
E=mc^2 says that there is a relationship between the two not that they are the same.
No, the photon has energy but no mass. If you don't believe it, you can have a look at the Particle Data Group informations:per.sundqvist said:To make a very simple answer of this: You are confusing the rest mass m0 with the total mass m. The more general version of E=mc^2 reads.
[tex]mc^2\equiv E=\sqrt{(pc)^2+(m_0c^2)^2}[/tex]
where m is the definition of the total mass in terms of E (the equation you wrote actually). So if m0=0 (for the photon) you get: m=p/c, where p, the momentum is given from the de Broglie relation [tex]p=h/\lambda[/tex]. Hence, the photon has BOTH mass and energy, by postulate (the equivalence principle [tex]E=m_{tot}c^2[/tex]).
Yes, I had understood what he intended .Dmitry67 said:no invariant mass - but it has a relativistic mass
I don't know what you intended with "pure energy", however a single photon has energy but not mass.malawi_glenn said:what we are trying to demonstrate is that mass and energy is the same thing, that there are no such thing as 'pure energy'
So you are not talking about "mass" in general, but specifically about "relativistic" mass.malawi_glenn said:what we are trying to demonstrate is that mass and energy is the same thing, that there are no such thing as 'pure energy'
lightarrow said:I don't know what you intended with "pure energy", however a single photon has energy but not mass.
About Higgs field, I cannot pronounce; about the rest, for what I see it, the distinction between (rest) mass and energy is simply the fact that in the first case, that is when a particle has (rest) mass, you can find a frame of reference in which the particle is stationary while in the second, when you have a particle with energy but no (rest) mass, you can't. So (rest) mass is nothing else than "energy that you can see when the particle is still".Dmitry67 said:BTW, does the 'rest'/'invariant' mass have any sense at all ?
- knowing that it is just an illusion, a result or how strongly massless particles (electrons, quarks, ...) interact with the Higgs field? :)
lightarrow said:So (rest) mass is nothing else than "energy that you can see when the particle is still".
No, dressed, it's winter here in ItalyDmitry67 said:(to add even more confusion)
Are we talking about the mass of the "naked" particles? :)
per.sundqvist said:To make a very simple answer of this: You are confusing the rest mass m0 with the total mass m. The more general version of E=mc^2 reads.
[tex]mc^2\equiv E=\sqrt{(pc)^2+(m_0c^2)^2}[/tex]
where m is the definition of the total mass in terms of E (the equation you wrote actually). So if m0=0 (for the photon) you get: m=p/c, where p, the momentum is given from the de Broglie relation [tex]p=h/\lambda[/tex]. Hence, the photon has BOTH mass and energy, by postulate (the equivalence principle [tex]E=m_{tot}c^2[/tex]).
malawi_glenn said:So what if 'massed' energy and 'photon' energy behaves differently, all forms of energy behaves differently in some way. What you have shown is just that an electron and a photon have different kinematical properties due to their rest mass. Nothing more.
I could impose that argument in a reverse order. "Now since photon energy behaves different that mass energy, photons can't be energy."
malawi_glenn said:Late edit: Why u think one calls the equation E = mc^2 "mass–energy equivalence formula" ?
enotstrebor said:Look up the definition of mass and the definition of energy. If you want to change the meaning and make the terms meaningless to you, feel free. They are not the same to the rest of the world and you are doing a disservice to those on this website by not acknowledging the difference.
It is called the "mass–energy equivalence formula" because it gives the euqivalent amount of energy held by a massed particle (mathematical energy value equivalence) if you could release all of the contained/particle energy. It does not say mass and energy are the same.
The fact that there is a 'E' (energy) term and a 'm' (mass) term in the equation is because the rest of the world understands that these are two different things. If they were the same there would not be two terms to mathematically describe them. QED
Because massed particles (one embodiment of energy) have different properties than photon particles (one embodiment of energy) we use different words to describe those differences of behavior (at least those who want clearity of thought and understanding).
"and words are grown so false I loath prove reason with them"
per.sundqvist said:I think the absolute or as it has been called here, the "relativistic mass" has impact in reallity. Photons, even though without rest mass are affected by gravity, in a complicated way though (general relativity theory). This must be due to its "mass" and not since it is "pure energy".
The whole concept of mass and matter is bound to be little mysterious since the days Newton defined it, roughly as m=F/a and also as a source for gravity field F=G*m1*m2/r^2. It need a reference to define a mass or another fixed way to define the force F=m*a, but what is then m? and so on. Energy is derived from Newtons equation, and then a little generalized in relativity, but still relies on that change of momentum (force) is related to mass. I know no other way, all I want to say is that its a mess!
Note also that the mass of the proton, which we can measure, is not given by the quarks rest masses! It gains that mass, around 10 times bigger than rest masses, because of its extreme confinement. It is the total relativistic mass that we see as external observers. The same must be true for the photons (but their mass are extremely small, and we have to deal with GR as well to take it into account).
enotstrebor said:First, E=mc^2 (E=mc^{2}) is universal for any velocity thus includes E=m_{0}c^{2}.
Second, momentum is different than mass, just as energy is different from mass. The equation [tex]p=h/\lambda[/tex] applied to the photon is only true for [tex]mc^2=E=\sqrt{(pc)^2+(m_0c^2)^2}[/tex] when in a vacuum and Thus Not A Fundamental Relationship For The Photon because;
the wavelength/momentum for the photon changes when not in a vacuum but the photon's energy does not.
As [tex]mc^2\equiv E=\sqrt{(pc)^2+(m_0c^2)^2}[/tex] is not universally true, the mathematical relationship is misleading.
If you ignore the distictive behavioral differences you are ignoring the physics. Mathematics is not physics. Mathematical relationships are relationships and are often true only in certain circumstances. When a mathematical relationship is not true under all circumstances it is clearly phenomenological and not fundamental.
Because mass is not additive...per.sundqvist said:You would agree in that charge is conserved in a reaction, like 0=-e+e, but not mass? My answer is that Yes, the photon has mass. If a container with photon gas has mass, why should not a single photon has mass?
per.sundqvist said:Clearly mathematics is not physics, but you must admit that "the power of the equality sign" has been quite successful so far!
1) [tex]p=h/\lambda[/tex] (waves has a momentum) [tex] \rightarrow\;\lambda=h/p[/tex] -> matter are waves!
2) [tex]E=mc^2[/tex] (mass contains energy) [tex]\rightarrow\;m=E/c^2[/tex] matter can be PRODUCED by any kind of energy!
2) is the most fruitful result by Einstein, not E=mc^2.
You would agree in that charge is conserved in a reaction, like 0=-e+e, but not mass? My answer is that Yes, the photon has mass. If a container with photon gas has mass, why should not a single photon has mass?
Perhaps I have misunderstood things here, but If it is the Higgs particle that GIVES particles their mass, Its would not exist -> Quite extreme prediction these days... But if it only intermediate mass in some way (like Feynman diagram Kirchoff current of mass) its OK, but why don't predict a "particle" that intermediate momentum and angular momentum at the same time? I here predict the momentum particle in the case you find the Higgs particle.
lightarrow said:Because mass is not additive...
lightarrow said:Because mass is not additive...