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E2 = m2c4 + p2c2So in the case of a photon, m=0 so E = pc or p = E/c.
a photon is basically pure energy, that it why it can go from particle to wave and visa versa..
Quote from: Emc2 on 10/09/2012 09:51:33E2 = m2c4 + p2c2So in the case of a photon, m=0 so E = pc or p = E/c.Ok.Quotea photon is basically pure energy, that it why it can go from particle to wave and visa versa..1. What is "pure energy" and which is the difference with "energy"?2. Just to be more precise, a photon doesn't "go from particle to wave and vice versa", a photon is a particle; as an electron, a proton, a neutron, ecc.But "particle" for a physicist doesn't mean "corpuscle". It actually means (simplistically speaking) "a quantum object which state is found solving the Schroedinger equation" and which has both wave and corpuscolar behaviour depending on the situation.
A Photon is energy
- and it has been proven that it can act as a wave or a particlehttp://en.wikipedia.org/wiki/Double-slit_experiment Like all elementary particles, photons are currently best explained by quantum mechanics and exhibit wave–particle duality, exhibiting properties of both waves and particles.
Quote from: Emc2 on 11/09/2012 07:23:28 A Photon is energyA photon "has" energy.Quote - and it has been proven that it can act as a wave or a particlehttp://en.wikipedia.org/wiki/Double-slit_experiment Like all elementary particles, photons are currently best explained by quantum mechanics and exhibit wave–particle duality, exhibiting properties of both waves and particles. "it can act as a wave or a particle" or "exhibit wave–particle duality" is a better description than the one you wrote in your previous post []
A Photon IS Energy, notice - definition from Goddard Space Center.. ( photonThe smallest (quantum) unit of light/electromagnetic energy. Photons are generally regarded as particles with zero mass and no electric charge. ) http://imagine.gsfc.nasa.gov/docs/dict_jp.html#photon
Quote from: Emc2 on 12/09/2012 06:07:34 A Photon IS Energy, notice - definition from Goddard Space Center.. ( photonThe smallest (quantum) unit of light/electromagnetic energy. Photons are generally regarded as particles with zero mass and no electric charge. ) http://imagine.gsfc.nasa.gov/docs/dict_jp.html#photonA photon is not energy, a photon has energy, and wherever you found that idea, sorry, it's wrong...In the link you gave there isn't written that "photon is energy", at all. Read it well.Energy is an attribute of objects/systems, it's not an object/system by itself.Otherwise you should explain (for example) how can a car have kinetic energy and not being a photon, or anything having energy and not having photons to which attribute that energy.
Quote from: lightarrow on 12/09/2012 20:33:52Quote from: Emc2 on 12/09/2012 06:07:34 A Photon IS Energy, notice - definition from Goddard Space Center.. ( photonThe smallest (quantum) unit of light/electromagnetic energy. Photons are generally regarded as particles with zero mass and no electric charge. ) http://imagine.gsfc.nasa.gov/docs/dict_jp.html#photonA photon is not energy, a photon has energy, and wherever you found that idea, sorry, it's wrong...In the link you gave there isn't written that "photon is energy", at all. Read it well.Energy is an attribute of objects/systems, it's not an object/system by itself.Otherwise you should explain (for example) how can a car have kinetic energy and not being a photon, or anything having energy and not having photons to which attribute that energy. first of all you did not read correctly.... (( photon, The smallest (quantum) unit of light/electromagnetic energy ) <---this is my quote...
Your are not correct. Think Again...
A Photon is Energy ( Radiation ),
and thereby "has" energy, and it has no mass.. you can accept the facts, or believe what you want to....
http://en.wikipedia.org/wiki/Photon ( A photon is an elementary particle,
the quantum of light and all other forms of electromagnetic radiation, and the force carrier for the electromagnetic force, even when static via virtual photons )http://en.wikipedia.org/wiki/Light ( In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. ) http://en.wikipedia.org/wiki/Electromagnetic_radiation ( the photon is the quantum of the electromagnetic interaction, and is the basic "unit" or constituent of all forms of EMR )
Quote from: Emc2 on 14/09/2012 06:00:05Quote from: lightarrow on 12/09/2012 20:33:52Quote from: Emc2 on 12/09/2012 06:07:34 A Photon IS Energy, notice - definition from Goddard Space Center.. ( photonThe smallest (quantum) unit of light/electromagnetic energy. Photons are generally regarded as particles with zero mass and no electric charge. ) http://imagine.gsfc.nasa.gov/docs/dict_jp.html#photonA photon is not energy, a photon has energy, and wherever you found that idea, sorry, it's wrong...In the link you gave there isn't written that "photon is energy", at all. Read it well.Energy is an attribute of objects/systems, it's not an object/system by itself.Otherwise you should explain (for example) how can a car have kinetic energy and not being a photon, or anything having energy and not having photons to which attribute that energy. first of all you did not read correctly.... (( photon, The smallest (quantum) unit of light/electromagnetic energy ) <---this is my quote...Ok, and then? It's taught in every simple course of qm. Does it mean that a photon is energy? LOLQuote Your are not correct. Think Again...I don't need it. If you like, ask a professor of physics...Quote A Photon is Energy ( Radiation ), "Is radiation and "is energy" are two different things. Radiation is something and energy is something else.A photon is a particle. Period. Then you can find that it has some properties, for example energy and spin. Quoteand thereby "has" energy, and it has no mass.. you can accept the facts, or believe what you want to.... Exactly, but this is what I wrote, you wrote that "a photon is energy".Quotehttp://en.wikipedia.org/wiki/Photon ( A photon is an elementary particle, Indeed []Quotethe quantum of light and all other forms of electromagnetic radiation, and the force carrier for the electromagnetic force, even when static via virtual photons )http://en.wikipedia.org/wiki/Light ( In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. ) http://en.wikipedia.org/wiki/Electromagnetic_radiation ( the photon is the quantum of the electromagnetic interaction, and is the basic "unit" or constituent of all forms of EMR )In all those quote, and in the links, there is never written that "a photon IS energy".
It is very complicated to understand, I realize that
.....but it is what it is, a mass less
piece of energy.....
First of all, everything is "pure energy"
thanks to Einstein's famous E=mc^2. Second of all: many elementary particles can decay; in fact, MOST of them! The only ones that don't are the electron, photon, up quark and (possibly) neutrino. The real reason that the photon cannot decay is because it is massless.
A counter-example is the Z boson, which is (VERY roughly speaking!!) a "fat photon", which can decay (and does so **VERY** fast - about 10^{-24} seconds!). However, it is just as "elementary" as the photon.
Massless particles can never decay.
You can prove this mathematically by just writing down the energies and momenta of the decay products and showing that there are no values of these things that conserve everything. More intuitively: massless particles move at the speed of light.
Particles that move at the speed of light do not experience "time" due to Einstein's special theory of relativity (infinite time dilation - they stop aging).
Quote from: Emc2 on 15/09/2012 05:27:02It is very complicated to understand, I realize thatYes, you are referring to yourself, clearly []Quote.....but it is what it is, a mass less Yes.Quotepiece of energy.....This is just your personal interpretation, if you want to discuss it, please do it in "New theories" forum.QuoteFirst of all, everything is "pure energy" "pure energy" doesn't exist. Please, ask a physics professor about what is "pure energy" and tell me how long you will have made him laugh...Quotethanks to Einstein's famous E=mc^2. Second of all: many elementary particles can decay; in fact, MOST of them! The only ones that don't are the electron, photon, up quark and (possibly) neutrino. The real reason that the photon cannot decay is because it is massless. And why a non-massless particle as electron doesn't decay?QuoteA counter-example is the Z boson, which is (VERY roughly speaking!!) a "fat photon", which can decay (and does so **VERY** fast - about 10^{-24} seconds!). However, it is just as "elementary" as the photon.This is just your personal interpretation, if you want to discuss it, please do it in "New theories" forum.QuoteMassless particles can never decay. I have never said the contrary (apart from the fact that I don't know what you mean with "decay": a photon can generate a couple e+ e-, for example)QuoteYou can prove this mathematically by just writing down the energies and momenta of the decay products and showing that there are no values of these things that conserve everything. More intuitively: massless particles move at the speed of light. Ok. And then? It doesn't mean that a photon IS energy or that something as "pure energy" exists. Why did you forget to define the term "pure energy"?QuoteParticles that move at the speed of light do not experience "time" due to Einstein's special theory of relativity (infinite time dilation - they stop aging).Meaningless sentence. You cannot create a frame of reference co-moving with the photon.
EMC2 - Lightarrow is completely correct. One might consider the photon as pure energy, but this is not the best way to think. Energy is a property of waves and particles. Classically you can view waves in the electromagnetic field as being carriers of energy. Energy is a property of the configuration. A more classical simile would be that sea waves quite clearly transporting energy - but they do not move a lot of water. You might still claim that waves are energy. But rather say it is more correct that energy is a property of the configuration and that waves transport energy.
Quote from: imatfaal on 15/09/2012 22:24:01EMC2 - Lightarrow is completely correct. One might consider the photon as pure energy, but this is not the best way to think. Energy is a property of waves and particles. Classically you can view waves in the electromagnetic field as being carriers of energy. Energy is a property of the configuration. A more classical simile would be that sea waves quite clearly transporting energy - but they do not move a lot of water. You might still claim that waves are energy. But rather say it is more correct that energy is a property of the configuration and that waves transport energy. No, I am sorry he is not correct, you both are not correct. Light is Energy.. and there nothing left to say about it..
first of all, I am rightread these links.
You'll notice that in those links there's always the important distinction that it is a packet of energy of the electromangetic field. If you just define a photon as a packet of energy you miss a lot of its important properties that come from the electromangetic field. As I understood their posts, that's what lightarrow and imatfaal were trying to point out.