Mass-Energy Equivalence
in [Relativity]
|
From: PD on 6 Apr 2010 15:26 On Apr 6, 8:14 am, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > You don't have photons 'till there is a causally > related absorption somewhere else and AFAIK no more > fundamental particles are known of. Fascinating. So let's see if I have this right. The sun has a certain power output, which corresponds to a certain number of photons per second by a rather straightforward calculation. But only a fraction of them are ever absorbed, and only a fraction of those are identified in an Earth laboratory as being photons. According to you, we are permitted to presume that the photons that are absorbed somewhere else are in fact photons, but that the ones that are not absorbed at all are not photons. So if the bulk of the sun's power output is not carried away by photons, then by what is all that energy carried? PD
From: Tony M on 6 Apr 2010 16:31 On Apr 6, 10:29 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Tony M wrote: > > Sue's example of electron-positron "annihilation" can be a bit > > misleading, making one believe that mass gets converted to energy, > > when that's not the case. > > Again this depends on the meanings of your words, including nuances. With > standard meanings we do say "mass is converted into kinetic energy". See below. > > > The isolated system consisting of the > > electron and positron has the same total energy and corresponding mass > > before and after the "annihilation", except now instead of electron > > and positron we have gamma photons (and maybe some other particles). > > e+ e- annihilate from rest into 2 gammas >99% of the time; the > other final states consist of 4,6,8,... gammas, or (very rarely) > neutrino anti-neutrino pairs. For simplicity, I'll only discuss > annihilation at rest into gammas. > > Normally we apply the word "mass" to OBJECTS, not to collections of unbound > objects. In the initial state the electron and the positron EACH have a mass, > and the total mass is 1.022 MeV/c^2. In the final state the gammas each have > zero mass, and the total mass is 0. The total energies of the initial and final > states are the same. The total kinetic energy of the initial state is 0, but the > total kinetic energy of the final state is 1.022 MeV. These units have c=1, and > it is obvious that mass was indeed converted to kinetic energy. > > This is relativity; the kinetic energy of an object is its > total energy minus its mass (c=1). > > Tom Roberts Sue, see what you did? Exactly what I was afraid of, you made Tom think one can convert mass to energy! Just kidding, he probably believed that all along. Guys, if you accept the following two statements then everything else will just fall into place: 1. The Law of Conservation of Energy is valid. 2. E=mc2 is valid (in all situations, not just at ones own convenience). If Tom admits that energy is conserved, then by E=mc2 => mass is conserved as well! Conservation of energy implies conservation of mass, theres no way around it! If Tom admits that photons have energy, then by E=mc2 => photons have mass as well! Energy and mass are bound for eternity by E=mc2. One cannot exist without the other, and theres nothing interpretable about that. It doesnt get more simple and obvious than that. Tom, ALL the initial mass is still there! Please read this: http://en.wikipedia.org/wiki/Mass and then go ahead and disagree with it if you want. Heres a fragment if you dont want to read the whole thing: In as much as energy is conserved in closed systems in relativity, the mass of a system is also a quantity which is conserved: this means it does not change over time, even as some types of particles are converted to others. For any given observer, the mass of any system is separately conserved and cannot change over time, just as energy is separately conserved and cannot change over time. The incorrect popular idea that mass may be converted to (massless) energy in relativity is due to the fact that some matter particles may in some cases be converted to types of energy which are not matter (such as light, kinetic energy, and the potential energy in magnetic, electric, and other fields). However, this confuses "matter" (a non-conserved and ill-defined thing) with mass (which is well-defined and is conserved). Even if not considered "matter," all types of energy still continue to exhibit mass in relativity. Thus, mass and energy do not change into one another in relativity; rather, both are names for the same thing, and neither mass nor energy appear without the other. "Matter" particles may not be conserved in reactions in relativity, but closed-system mass always is.
From: PD on 6 Apr 2010 16:55 On Apr 6, 3:31 pm, Tony M <marc...(a)gmail.com> wrote: > On Apr 6, 10:29 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > > > > > Tony M wrote: > > > Sue's example of electron-positron "annihilation" can be a bit > > > misleading, making one believe that mass gets converted to energy, > > > when that's not the case. > > > Again this depends on the meanings of your words, including nuances. With > > standard meanings we do say "mass is converted into kinetic energy". See below. > > > > The isolated system consisting of the > > > electron and positron has the same total energy and corresponding mass > > > before and after the "annihilation", except now instead of electron > > > and positron we have gamma photons (and maybe some other particles). > > > e+ e- annihilate from rest into 2 gammas >99% of the time; the > > other final states consist of 4,6,8,... gammas, or (very rarely) > > neutrino anti-neutrino pairs. For simplicity, I'll only discuss > > annihilation at rest into gammas. > > > Normally we apply the word "mass" to OBJECTS, not to collections of unbound > > objects. In the initial state the electron and the positron EACH have a mass, > > and the total mass is 1.022 MeV/c^2. In the final state the gammas each have > > zero mass, and the total mass is 0. The total energies of the initial and final > > states are the same. The total kinetic energy of the initial state is 0, but the > > total kinetic energy of the final state is 1.022 MeV. These units have c=1, and > > it is obvious that mass was indeed converted to kinetic energy. > > > This is relativity; the kinetic energy of an object is its > > total energy minus its mass (c=1). > > > Tom Roberts > > Sue, see what you did? Exactly what I was afraid of, you made Tom > think one can convert mass to energy! Just kidding, he probably > believed that all along. > > Guys, if you accept the following two statements then everything else > will just fall into place: > 1. The Law of Conservation of Energy is valid. > 2. E=mc2 is valid (in all situations, not just at ones own > convenience). But it's not. The energy in that specific relation was not intended to be the total energy of a system or even of a moving object. It was intended to describe a *rest energy*, associated with the *rest* mass of a particle. That is only one contribution to a particle's energy or a system's energy. There was a dalliance for a while where scientists talked about a "relativistic mass" where E would represent the total energy of an object, and then the mass was something completely different than the invariant mass or the rest mass of the object. However, that notion has fallen out of favor and common usage, because it leads precisely to the kind of muddle you find yourself in. > > If Tom admits that energy is conserved, then by E=mc2 => mass is > conserved as well! Conservation of energy implies conservation of > mass, theres no way around it! > > If Tom admits that photons have energy, then by E=mc2 => photons have > mass as well! > > Energy and mass are bound for eternity by E=mc2. One cannot exist > without the other, and theres nothing interpretable about that. It > doesnt get more simple and obvious than that. > > Tom, ALL the initial mass is still there! Please read this:http://en.wikipedia.org/wiki/Mass > and then go ahead and disagree with it if you want. > > Heres a fragment if you dont want to read the whole thing: > In as much as energy is conserved in closed systems in relativity, > the mass of a system is also a quantity which is conserved: this means > it does not change over time, even as some types of particles are > converted to others. For any given observer, the mass of any system is > separately conserved and cannot change over time, just as energy is > separately conserved and cannot change over time. The incorrect > popular idea that mass may be converted to (massless) energy in > relativity is due to the fact that some matter particles may in some > cases be converted to types of energy which are not matter (such as > light, kinetic energy, and the potential energy in magnetic, electric, > and other fields). However, this confuses "matter" (a non-conserved > and ill-defined thing) with mass (which is well-defined and is > conserved). Even if not considered "matter," all types of energy still > continue to exhibit mass in relativity. Thus, mass and energy do not > change into one another in relativity; rather, both are names for the > same thing, and neither mass nor energy appear without the other. > "Matter" particles may not be conserved in reactions in relativity, > but closed-system mass always is.
From: mpc755 on 6 Apr 2010 17:28 http://cfa-www.harvard.edu/Walsworth/pdf/PT_Romalis0704.pdf "A possible candidate for dark energy that avoids some of the fine- tuning problems associated with the cosmological is quintessence, a very low-energy field with a wavelength comparable to the size of the known universe. In addition to its effect on the expansion of the universe, quintessence might also manifest itself through its possible interactions with matter and radiation." http://dictionary.reference.com/browse/quintessence "quin·tes·sence â â/kwɪnËtÉsÉns/ Show Spelled[kwin-tes-uhns] Show IPA ânoun 1. the pure and concentrated essence of a substance. 2. the most perfect embodiment of something. 3. (in ancient and medieval philosophy) the fifth essence or element, ether, supposed to be the constituent matter of the heavenly bodies" A low-energy field with a wavelength comparable to the size of the known universe is aether as a one something. Aether and matter are different states of the same material. Aether is the pure essence of matter. "quintessence might also manifest itself through its possible interactions with matter" Aether interacts with matter by being displaced by matter. The pressure exerted by aether displaced by matter manifests itself as gravity. The physical effects the expansion of matter transitioning to aether has on the neighboring matter and aether manifests itself as energy. Aether and matter are different states of the same material. Matter is compressed aether and aether is uncompressed matter. 'DOES THE INERTIA OF A BODY DEPEND UPON ITS ENERGY-CONTENT? By A. EINSTEIN' http://www.fourmilab.ch/etexts/einstein/E_mc2/e_mc2.pdf "If a body gives off the energy L in the form of radiation, its mass diminishes by L/c2." The mass of the body does diminish, but the matter which no longer exists as part of the body has not vanished. It still exists, as aether. As the matter transitions to aether it expands in three dimensions. The effect this transition has on the surrounding aether and matter is energy.
From: BURT on 6 Apr 2010 17:33
On Apr 6, 2:28 pm, mpc755 <mpc...(a)gmail.com> wrote: > http://cfa-www.harvard.edu/Walsworth/pdf/PT_Romalis0704.pdf > > "A possible candidate for dark energy that avoids some of the fine- > tuning problems associated with the cosmological is quintessence, a > very low-energy field with a wavelength comparable to the size of the > known universe. In addition to its effect on the expansion of the > universe, quintessence might also manifest itself through its possible > interactions with matter and radiation." > > http://dictionary.reference.com/browse/quintessence > > "quin·tes·sence > â â/kwɪnËtÉsÉns/ Show Spelled[kwin-tes-uhns] Show IPA > ânoun > 1. the pure and concentrated essence of a substance. > 2. the most perfect embodiment of something. > 3. (in ancient and medieval philosophy) the fifth essence or element, > ether, supposed to be the constituent matter of the heavenly bodies" > > A low-energy field with a wavelength comparable to the size of the > known universe is aether as a one something. > > Aether and matter are different states of the same material. > > Aether is the pure essence of matter. > > "quintessence might also manifest itself through its possible > interactions with matter" > > Aether interacts with matter by being displaced by matter. > > The pressure exerted by aether displaced by matter manifests itself as > gravity. > > The physical effects the expansion of matter transitioning to aether > has on the neighboring matter and aether manifests itself as energy. > > Aether and matter are different states of the same material. > > Matter is compressed aether and aether is uncompressed matter. > > 'DOES THE INERTIA OF A BODY DEPEND UPON ITS ENERGY-CONTENT? By A. > EINSTEIN'http://www.fourmilab.ch/etexts/einstein/E_mc2/e_mc2.pdf > > "If a body gives off the energy L in the form of radiation, its mass > diminishes by L/c2." > > The mass of the body does diminish, but the matter which no longer > exists as part of the body has not vanished. It still exists, as > aether. As the matter transitions to aether it expands in three > dimensions. The effect this transition has on the surrounding aether > and matter is energy. The spherical geometry of gravity is important. It has a center. Mitch Raemsch |