martillo

The thermal equilibrium I'm conceiving is something different. Is not related to the kinetic energy of the particle. I consider the particle is capable to absorb and emit EM radiation (photons). All atoms have their characteristic levels of energy in accordance to the levels of its electrons. All atoms have their characteristic spectra. When electrons jump to other levels they absorb or emit photons. In a thermal equilibrium with its environment the particle continuously absorbs and emits photons maintaining an average level of energy. Those photons constitute the EM radiation present in the environment called thermal radiation and it has a temperature associated to it. The temperature is related to the density of the power of the radiation per unity of area according to the Stefan-Boltzmann Law: P/A = σT4

Yes there is. It is called thermal radiation. It is the only thing that exist in the interior of a perfect black body and it is the thing it emits. See: https://en.wikipedia.org/wiki/Black-body_radiation For instance: "Black-body radiation is the thermal electromagnetic radiation within, or surrounding, a body in thermodynamic equilibrium with its environment, emitted by a black body (an idealized opaque, non-reflective body). It has a specific, continuous spectrum of wavelengths, inversely related to intensity, that depend only on the body's temperature, which is assumed, for the sake of calculations and theory, to be uniform and constant.[1][2][3][4] As the temperature of a black body decreases, the emitted thermal radiation decreases in intensity and its maximum moves to longer wavelengths. Shown for comparison is the classical Rayleigh–Jeans law and its ultraviolet catastrophe. A perfectly insulated enclosure which is in thermal equilibrium internally contains blackbody radiation, and will emit it through a hole made in its wall, provided the hole is small enough to have a negligible effect upon the equilibrium. The thermal radiation spontaneously emitted by many ordinary objects can be approximated as blackbody radiation." and: "Black body[edit] Main article: Black body All normal (baryonic) matter emits electromagnetic radiation when it has a temperature above absolute zero. The radiation represents a conversion of a body's internal energy into electromagnetic energy, and is therefore called thermal radiation. It is a spontaneous process of radiative distribution of entropy. Conversely, all normal matter absorbs electromagnetic radiation to some degree. An object that absorbs all radiation falling on it, at all wavelengths, is called a black body. When a black body is at a uniform temperature, its emission has a characteristic frequency distribution that depends on the temperature. Its emission is called blackbody radiation." Yes it works. "kT is directly related to mv^2 (with a constant related to degrees of freedom)" continues to be right. It is just that there's the extra "bunch of EM radiation interior to the system" in the system may be not taken into account. If I can explain the thing with real existent particles (the photons) why would I appeal to the mathematical artifice of "virtual particles" (phonons)? There is no such thing. You mean it is not being considered. I can define it as below. I can define the temperature of an atom (as of that any material object) in thermal equilibrium with its surrounding environment as being the same as that of the environment which can be measured by a thermometer.

There must be EM energy in the interior of the system. In a totally empty space, without EM radiation, the particles (atoms/molecules) would lose all their internal energy becoming totally cold (0º K). All the electrons of them jumping to their minimum level of energy possible radiating all the possible internally accumulated energy. Some temperature higher than the 0º K can be reached only in a dynamical equilibrium in which the particles continuously absorb and emit some quantity of EM radiation. You can think in photons in the interior of the system travelling in all directions.

Is just me failing to explain the phenomenon properly. I completely agree with the Kinetic Theory at all times. We have a system of particles occupying a volume V and having some temperature T verifying PV = NKT. The temperature T is related to the intensity of the thermal energy present in the interior (not a direct relation: Stefan-Boltzmann Law). The kinetic energies of the particles produce the pressure P because of their momentum. The system is heated with incoming external EM radiation. Enough EM energy to augment its temperature in such a way that a new set of values verify these equations for a new thermal equilibrium reached. Right. The temperature is related to the thermal energy of the system but is not a direct relation, they verify Stefan-Boltzmann Law. What I'm trying to say is just that the temperature T (measured by a thermometer) is more related to the energy of the internal EM radiation present in the interior while the pressure P is more related to the momentum of the particles and so their kinetic energy even though they are all interrelated by those two equations. I must remind here that the only disagreement I have in all this is that I think in an EM energy stored in the internal electromagnetic structure of the particles and not as a vibration in their atoms. As for now I don't have an evidence in favor of this although I'm thinking about. Meanwhile all I can do is to try to show that everything could be also well explained under this assumption.

I have been thinking in this your point against my approach of the absorbed EM radiation stored in the internal electromagnetic structure of atoms/molecules. Your objection is related to the fact that in this case the emission spectrum would be discrete according to the discrete levels of energy of the atoms (discrete quantum levels of energy of the electrons in the atoms). I'm considering now that the original discrete spectrum is lost to a continuous one due to the "Compton scattering" interactions of the originally emitted photons with the electrons (free or bounded) they find while travelling from inside the body you are analyzing to the outside. Also other electrons could be found outside in the environment traveled before reaching the final energy measuring place. They would also contribute to more Compton scattering on the original photons. The original photons' energy could be altered in infinite possible ways and so a continuous spectrum is produced at the end.

I said I was thinking about the subject. I don't have evidence, at least yet. May be the spectrum could be continuous after all. Good point, I must think about. Energy is conserved. I didn't explain it properly. I'm considering the EM radiation that enters in a volume of gas' particles increasing its temperature. Energy must be supplied to the system to augment its temperature. An EM radiation has momentum and so the supplied one enters in the volume colliding with the existent particles altering their movement (I mean linear movement not "vibration"). In average extra energy is delivered to the particles augmenting their kinetic energy. Once a new thermal equilibrium is reached the moving particles also absorb and emit radiation and a new equilibrium is reached between the moving particles and the EM radiation present in the volume of the system. The total intensity of the radiation depends on the quantity of the emitting particles. A 100L of water contains more emitting particles than a 1 cm3 chunk of solid and so the intensity of the radiation (quantity of energy radiated) by the 100L of water would be higher.

I don't understand how "collisional energy" can produce EM radiation. Can you explain that? On the other side I think I understand how it is produced by "electrons jumping between states". I also stay thinking now that may be at the end the radiated energy from a black body could actually be not a continuum but discrete in minimal increments as originally considered by Planck. As said at Wikipedia (https://en.wikipedia.org/wiki/Planck's_law) : At the end of the 19th century, physicists were unable to explain why the observed spectrum of black-body radiation, which by then had been accurately measured, diverged significantly at higher frequencies from that predicted by existing theories. In 1900, German physicist Max Planck heuristically derived a formula for the observed spectrum by assuming that a hypothetical electrically charged oscillator in a cavity that contained black-body radiation could only change its energy in a minimal increment, E, that was proportional to the frequency of its associated electromagnetic wave. While Planck originally regarded the hypothesis of dividing energy into increments as a mathematical artifice, introduced merely to get the correct answer, other physicists including Albert Einstein built on his work, and Planck's insight is now recognized to be of fundamental importance to quantum theory. I'm not thinking in EM radiation as an alternative to to the kinetic theory of temperature. I'm saying that the EM radiation is the cause for the particles to acquire their kinetic energy and that temperature is a magnitude related to its intensity. The Kinetic Theory of Gases with its main law PV = NKT, for instance, remains exactly the same. I do not modify anything in it. I'm just saying that temperature actually measures the EM radiation present in the volume which is related to the kinetic energy of the particles by that equation.

Just something may be wrong. Thinking about...

What do you think cannot be explained this way? Think in EM radiation as an intermediary in the transferring of kinetic energy between particles when no direct collisions are present. It is well known metals are excellent in absorbing and emitting EM radiation. No free electrons involved. Right, thanks for the comment. I would just correct that the same way thermal energy can be absorbed in the static structure the inverse can also happen, the energy gained in the structure can be transformed again into thermal energy while emitting EM radiation contributing to the temperature.

Not ridiculous if you consider that EM radiation has momentum and carries energy (in both models: electromagnetic wave or photon). This way EM radiation can produce movement and kinetic energy when colliding with atoms or molecules. KMT theory is not altered by this, by the way, it offers a good explanation of some things.

Einstein's conclusion is related to the inertial mass, this means the mass at "rest" and the total energy which includes the kinetic energy. If a massive object absorbs EM energy it augments its inertial mass, the "rest mass". This means the object stores the EM energy in its internal structure which in principle could involve internal vibration, I agree, but also could be stored in the non vibrating static electromagnetic field of the structure. In principle both cases are possible. Why not to consider the second one? Temperature is a magnitude related to the intensity of the EM radiation emitted by an object. An object that increases its internal energy emits more EM radiation and so its temperature is increased. For instance the electrons in the atoms can absorb extra EM energy reaching configurations of higher levels of energy in the atom and being capable to jump to lower levels emitting correspondent EM energy. This implies more energy radiated by the object and so a higher temperature. This is the way EM energy can be absorbed by an object without involving a kinetic vibration of the atoms. Seems to me temperature can be explained in both ways, with or without vibrating atoms. I would prefer the second one with no vibrations.

The main question of the OP is: I will try to explain my reasoning in a more comprehensible way. I have found very appropriated to mention what Einstein said about the subject because just applying classical electrodynamics he reached to the conclusion that If a body absorbs an EM energy ΔE its inertial mass augments in Δm = ΔE/c2. This gives us the notion that if a massive object absorbs EM radiation it stores it internally in its basic structure constituted by the nucleus and the surrounding electrons of the atoms of the object. This can be applied to any kind of object, solid, liquid, gas, whatever. We can think they are all constituted by nucleus of atoms and electrons everything linked by some bonds and those bonds made by electromagnetic forces. We can think then that the energy is stored as an electromagnetic energy in an entire electromagnetic structure. I think this is totally compatible with the notion of "lattice vibrations" in crystalline metallic structures as @exchemist mentioned although I don't think they need to vibrate. I think the same is accomplished with static structures where the lattice distances can vary accordingly. Furthermore I think the same reasoning would apply to any material object, metallic or not and even for isolated molecules and I think the same could in principle be extended to isolated atoms but I must agree this is just a thought of mine and not having any credited reference to mention. Hope my reasoning could have sense now...

I think the wiki is right, the temperature of an atom is directly related to the energy of the bounding of the electrons in the atom. When an atom absorbs EM radiation it gets "excited". You can think in terms of the equation E =mc2. According to it, and as Einstein said, a "body" of mass m can absorb some quantity ΔE of EM radiation augmenting its mass in a quantity Δm = ΔE/c2. Mass is something directly related to the internal energy of a "body" and in your case of an atom. Seems to me you are getting confused with the gases behavior in which "heat" is absorbed verifying the gases' law PV = nRT. In this case part of the energy of a radiation is transformed to some kinetic energy on the atoms/molecules and then the gases can exert pressure in a closed volume but the temperature of the gases is the temperature of its atoms/molecules as described above.

So, two large threads devoted to the discussion about "free will" and there's no agreement even in its definition yet. Well, we are in the Philosophy forum and in general Philosophy limits itself to present the positions of different philosophers and does not resolve which is right or wrong leaving to the readers the possibility to choose one or even develop yet other one of his own if that would be possible. I don't expect any agreement in these discussions, endless discussions...

Yes, another planet, other sun, without dangerous cosmic rays, no asteroids that could provoque massive extinctions, in other galaxy because this one is going to collide with the near Andromeda galaxy and so on. Would there be a really good place for people to live a really good life in the entire universe? I think not. May be in other universe and may be even with some change in the physics' laws, not this one.

Yes, lot of coincidences allow life in this planet and still with lot of problems. The reality is hard, nothing easy. Sure and many species got extinct. Even our own future is not very certain after all.

Too much diseases, calamities, catastrophes and tragedies. Seems the Universe is not well "tunned" for an ideal kind of life. We live as we can...

May be I have read your post too fast. I thought you were making that association, something I didn't like. I got confused, I agree. May be yes. English is not my natural language and I get confused sometimes. Negative -1 reaction to your post removed.

Your post is not an objective overview. You are just promoting your compatibilist position here. For instance: The libertarian position does not say that. It says that people can change their situation because the future is undetermined and their choices and actions can influence the future. Of course without total certainty because everything depends not only in our choices and decisions but also in the conditions of the situation, the environment, other people, society, etc, and even the luck because randomness also plays a role in the universe which is yet another source of indeterminism in the future. You just want to promote your position here. It is not a look for the real true thing. Useless discussion for me.

Thanks. I'll look further on this subject.

I have highlighted a point I am particularly interested. As you say voltmeters actually measure current. The current passes through an internal resistance and they take the voltage over that resistance to move a needle or generate a number in a digital display. Two questions: In which way could a voltage be measured directly? Is there any known case where the voltage has been measured directly? I'm particularly interested about high voltage measurements.

I was reading something about that Schrodinger found problems in the development of his equation with some things related to Relativity and so he at the end developed a non relativistic equation. The relativistic Klein-Gordon equation was developed after. Lot of new things being developed quite at the same time in those years... Seems I would need to enter deeper into QM to be able to understand the thing... I just want to ask you now the same as to @joigus:

What I don't get is that you have E, you have p so, why can't you have E/p. What does the quotient E/p means to you? Why to not just associate vp = E/p? I don't get it. As I already said to @joigus "quantum uncertainty" just puts a limit in the precision on the determination of some quantity. It does not means some quantity would be not determinable. Different things.

I still don't get it. We cannot see energy or momentum but we can determine their values. Not observable, not directly measurable but determinable. Why not the same for the phase velocity? If the energy E and the momentum p can be determined the quantity E/p is determinable and so vp = E/p is determinable. The uncertainty principle puts a limit in the precision of the determination of course but this does not mean is not determinable. It would be determinable under an appropriated degree of certainty.

Could I say then that the phase is not measurable but it is determinable? I mean we cannot experimentally measure it but we could determine it. Could it has sense this way? "Matter waves" could be just abstract things in our mind but we should be able to know about their properties like their wavelength, their group velocity and why not their phase velocity? "Particles", "waves", everything is just models in our minds but why we cannot have good models with well determined properties? Isn't it the main purpose of Physics to elaborate good models for everything? We should be able to know all the properties of those models even if they were just abstractions in our minds...