A simple Q. but not a simple A,,
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From: Inertial on 28 Dec 2009 07:28 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:f9046d7d-1433-4222-a84a-21ba9a89b1a8(a)j42g2000yqd.googlegroups.com... > On 28 Dec, 07:44, "Y.Porat" <y.y.po...(a)gmail.com> wrote: >> >> THE PHOTON HAS MASS !! > > Of course the photon has mass. All energy has mass. But it has no rest mass (which is what is meant when one just says "mass"). Because a photon has no rest energy. A lot of people are confused by E = mc^2 and what it means and when it applies.
From: Inertial on 28 Dec 2009 07:34 "Y.Porat" <y.y.porat(a)gmail.com> wrote in message news:cdec677e-ef7b-4ad1-aeb9-0d02bfe87c7a(a)e27g2000yqd.googlegroups.com... > On Dec 28, 1:44 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> On 28 Dec, 07:44, "Y.Porat" <y.y.po...(a)gmail.com> wrote: >> >> >> >> > THE PHOTON HAS MASS !! >> >> Of course the photon has mass. All energy has mass. > > ---------------- > good for you! > just tell it to all idiotic parrots > energy is > mass in motion!! Not always > exactly as in macrocosm !!! Not always > not to mention that mass is > in the dimensions of energy !! Yeup .. Mass is equivalent to energy. That doesn't mean a photon has rest (or invariant) mass. It does have an amount of mass equivalent to its energy (which is observer dependant). If it had invariant mass, then that mass would be the same for all observers. Its not.
From: Inertial on 28 Dec 2009 07:41 "Y.Porat" <y.y.porat(a)gmail.com> wrote in message news:4633bae8-bb7b-4854-9ca0-bb1b5f62b563(a)a32g2000yqm.googlegroups.com... > On Dec 28, 2:04 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "Y.Porat" <y.y.po...(a)gmail.com> wrote in message >> >> news:f443926e-9fb3-4d6a-9c85-cae0fe2bfe63(a)a32g2000yqm.googlegroups.com... >> >> >> >> > On Dec 27, 1:59 am, Sam Wormley <sworml...(a)gmail.com> wrote: >> >> On 12/26/09 5:42 PM, Spencer Spindrift wrote: >> >> >> > Q.: How is it that a photon has momentum but no mass? >> >> > Or in other words how does light carry energy? >> >> > As far as I know momentum is a property of moving or spinning >> >> > mass. >> >> > A photon cannot have mass or it would be infinite at C.. >> >> >> > A.; ??? >> >> >> Some properties of photons based on measurements >> >> For inertial observers, photons propagate at c >> >> >> From the quantum mechanical perspective >> >> >> 1. photons are emitted (by charged particles) >> >> 2. photons propagate at c >> >> 3. photons are absorbed (by charged particles) >> >> >> Photon momentum >> >> p = hν/c = h/λ >> >> >> Photon Energy >> >> E = hν >> >> >> Particle Chart - Standard Model >> >> http://www.astro.wisc.edu/~heroux/images/Particle_chart.jpg >> >> >> Conservation of momentum holds. One way to measure photon >> >> momentum is to it to measure the change in momentum of what >> >> absorbs or emits a photon. >> >> > ------------------- >> > the Planck constant HAS MASS !! >> >> No .. it has DIMENSIONS of mass. It doesn't HAVE mass .. it would need >> to >> be an actual physical entity to have mass. All it is is a numerical >> relationship between energy and frequency (and occurs in a number of >> formulas) .. the dimensions of it are simply what is required to make >> dimensional analysis work for the formula that expresses that >> proportionality. >> >> > got it parrot orchestra conductor !! >> >> Clearly you don't, and instead think that 'h' having dimensions of mass >> (among others) is somehow significant, and that saying it somehow acts >> like >> a magical incantation to refute the statements he made. Odd. > > ----------------- > psychopath Feuerbacher You're clearly confused .. that's not me > go discuss with Goebbels not with me I note that you are incapable of addressing the valid physics arguments I make. Instead you resort to your pathetic insults.
From: Androcles on 28 Dec 2009 16:03 "Anti Vigilante" <antivigilante(a)pyrabang.com> wrote in message news:hhb5rj$gdk$1(a)news.eternal-september.org... >>> It can't reach c. >>> >>> Every experiment to find a mass for a photon has come up with zero (as >>> far as experiment can tell). >>> >>> What is the mass for a photon .. you seem to think formulas give it .. >>> you said we have momentum of a photon is >>> >>> p = m . c >>> >>> But we also have >>> >>> p = h / l >>> >>> where l is the wavelength of the photon, so >>> >>> m = h / l / c >>> >>> So you should be easily able to work out what your claimed mass for a >>> photon >>> of a given frequency and wavelength is (save some gamma radiation, with >>> wavelength of order of 10x-16). >>> >>> Do a calculation and see. >>> >>> Of course .. you'll find the the mass of a photon then varies depending >>> on who observes it, because its energy and momentum are observer >>> dependant. >>> >>> How do you explain the rest mass of a single photon varying like that >>> .. if >>> there is only one mass? >>> > > Simple the variation comes from the varying quantity namely frequency. > Since mass does not vary therefore the mass comes from Planck's constant. > > Question is what the hell does frequency have to do with energy? > Frequency implies cyclical behavior. ================================================= The faster the wheel turns the faster it travels the road. The bigger the wheel the slower it needs to turn. If you insist it only has one speed then you'll be perplexed by the obvious.
From: Inertial on 28 Dec 2009 18:28
"Anti Vigilante" <antivigilante(a)pyrabang.com> wrote in message news:hhauip$e88$1(a)news.eternal-september.org... > On Mon, 28 Dec 2009 23:04:19 +1100, Inertial wrote: > >> "Y.Porat" <y.y.porat(a)gmail.com> wrote in message >> news:f443926e-9fb3-4d6a-9c85- > cae0fe2bfe63(a)a32g2000yqm.googlegroups.com... >>> On Dec 27, 1:59 am, Sam Wormley <sworml...(a)gmail.com> wrote: >>>> On 12/26/09 5:42 PM, Spencer Spindrift wrote: >>>> >>>> > Q.: How is it that a photon has momentum but no mass? >>>> > Or in other words how does light carry energy? As far as I >>>> > know momentum is a property of moving or spinning >>>> > mass. >>>> > A photon cannot have mass or it would be infinite at C.. >>>> >>>> > A.; ??? >>>> >>>> Some properties of photons based on measurements For inertial >>>> observers, photons propagate at c >>>> >>>> From the quantum mechanical perspective >>>> >>>> 1. photons are emitted (by charged particles) 2. photons >>>> propagate at c >>>> 3. photons are absorbed (by charged particles) >>>> >>>> Photon momentum >>>> p = hν/c = h/λ >>>> >>>> Photon Energy >>>> E = hν >>>> >>>> Particle Chart - Standard Model >>>> http://www.astro.wisc.edu/~heroux/images/Particle_chart.jpg >>>> >>>> Conservation of momentum holds. One way to measure photon momentum >>>> is to it to measure the change in momentum of what absorbs or emits >>>> a photon. >>> >>> ------------------- >>> the Planck constant HAS MASS !! >> >> No .. it has DIMENSIONS of mass. It doesn't HAVE mass .. it would need >> to be an actual physical entity to have mass. All it is is a numerical >> relationship between energy and frequency (and occurs in a number of >> formulas) .. the dimensions of it are simply what is required to make >> dimensional analysis work for the formula that expresses that >> proportionality. > > Except Newtons have dimensions of mass which multiplied by distance have > the value of Work which has the same dimensions as energy. Yes they do. That doesn't mean work if an entity that has a mass. > What's the point of dimensional analysis if you can just wave it all away > by claiming it's purely mathematical? No-one said to wave it away. There is a difference between a number having dimensions of mass, and saying it has mass. It can't have mass .. its jsut a number. Its not a measurement of a physical entity. Its a numerical proportion. > Incidentally Energy also has dimensions of mass. Which is why the constant proportion 'h' has dimension of mass (among others) .. it is given whatever dimensions that are required to satisfy dimensional analysis. |