On Saturday, March 23, 2019 at 2:19:39 PM UTC-6, Brent wrote: > > > > On 3/23/2019 5:45 AM, [email protected] <javascript:> wrote: > > > > On Thursday, March 21, 2019 at 12:40:13 AM UTC-6, smitra wrote: >> >> On 21-03-2019 06:21, [email protected] wrote: >> > On Wednesday, March 20, 2019 at 12:51:18 PM UTC-6, Brent wrote: >> > >> >> On 3/20/2019 3:07 AM, [email protected] wrote: >> >> >> >> On Tuesday, March 19, 2019 at 7:23:29 PM UTC-6, Brent wrote: >> >> >> >> On 3/19/2019 9:32 AM, John Clark wrote: >> >> >> >> On Tue, Mar 19, 2019 at 4:50 AM <[email protected]> wrote: >> >> >> >>> I SUPPOSE EINSTEIN STARTED WITH THE MOTIVATION OF FINDING A >> >> GENERAL TRANSFORMATION FROM ONE ACCELERATING FRAME TO ANOTHER, AND >> >> LATER GAVE UP ON THIS PROJECT AND SETTLED FOR A THEORY OF GRAVITY. >> >> IS THIS TRUE? TIA, AG >> >> >> >> Einstein's breakthrough, what he called "the happiest thought of my >> >> life" was when he realized a man in a falling elevator will not feel >> >> gravity but a man in a accelerating elevator will. In other words an >> >> accelerating frame and gravity are the same thing, that's why it's >> >> called the Equivalence Principle. >> > >> > I wonder if Einstein ever considered whether a charged particle in >> > the falling radiate would radiate? >> > >> > Brent >> > >> > Because of your typos, at first I thought you were joking. Well, maybe >> > it was a joke, but for me it sounds like a damned good question. I >> > surmise that a charged particle accelerating due to gravity does NOT >> > radiate energy, but why? AG >> > >> > Sorry about the typos. Yes, it does seem paradoxical. Here's a >> > paper that purports to solve the problem. >> > >> > THE RADIATION OF A UNIFORMLY ACCELERATED CHARGE IS BEYOND THE HORIZON: >> > A SIMPLE DERIVATION >> > >> > Camila de Almeida [1], Alberto Saa [2] >> > (Submitted on 6 Jun 2005 (v1 [3]), last revised 2 Dec 2005 (this >> > version, v5)) >> > >> >> We show, by exploring some elementary consequences of the covariance >> >> of Maxwell's equations under general coordinate transformations, >> >> that, despite inertial observers can indeed detect electromagnetic >> >> radiation emitted from a uniformly accelerated charge, comoving >> >> observers will see only a static electric field. This simple >> >> analysis can help understanding one of the most celebrated paradoxes >> >> of last century. >> > >> > Comments: >> > Revtex, 6 pages, 2 figures. v2: Some small >> corrections. v3: >> > Citation of a earlier paper included. v4: Some stylistic changes. v5: >> > Final version to appear in AJP >> > >> > Subjects: >> > Classical Physics (physics.class-ph); General >> Relativity and >> > Quantum Cosmology (gr-qc) >> > >> > Journal reference: >> > Am.J.Phys. 74 (2006) 154-158 >> > >> > DOI: >> > 10.1119/1.2162548 [4] >> > >> > Cite as: >> > arXiv:physics/0506049 [5] [physics.class-ph] >> > >> > (or arXiv:physics/0506049v5 [6] [physics.class-ph] for >> this >> > version) >> > >> > And another paper that looks at possible experimental evidence. >> > >> > ELECTRICAL CHARGES IN GRAVITATIONAL FIELDS, AND EINSTEIN'S >> > EQUIVALENCE PRINCIPLE >> > >> > Gerold Gründler [7] >> > (Submitted on 14 Sep 2015 (v1 [8]), last revised 12 Oct 2015 (this >> > version, v3)) >> > >> >> According to Larmor's formula, accelerated electric charges radiate >> >> electromagnetic waves. Hence charges should radiate, if they are in >> >> free fall in gravitational fields, and they should not radiate if >> >> they are supported at rest in gravitational fields. But according to >> >> Einstein's equivalence principle, charges in free fall should not >> >> radiate, while charges supported at rest in gravitational fields >> >> should radiate. In this article we point out indirect experimental >> >> evidence, indicating that the equivalence principle is correct, >> >> while the traditional interpretation of Larmor's formula must be >> >> amended. >> > >> > Subjects: >> > General Physics (physics.gen-ph) >> > >> > Cite as: >> > arXiv:1509.08757 [9] [physics.gen-ph] >> > >> > (or arXiv:1509.08757v3 [10] [physics.gen-ph] for this >> version) >> > >> > However, I don't find them entirely convincing. We know that double >> > stars, which are orbiting one another in free-fall, radiate >> > gravitational waves. Are we to suppose that if one or both of them >> > had an electrical charge that there would be no EM radiation? >> > >> > Brent >> > >> > IF WE GO BACK TO CLASSICAL E&M, WHERE DOES THE EM RADIATION COME FROM >> > WHICH IS EMITTED FOR ACCELERATING PARTICLES? IT CAN'T COME FROM >> > THE SELF FIELD OF, SAY, AN ELECTRON, SINCE THAT WOULD IMPLY LOSS OF >> > MASS OR CHARGE OF THE ELECTRON, WHICH IS NEVER CLAIMED. SO IT MUST >> > COME FROM THE EM FIELD CAUSING THE ACCELERATION. NOW IF WE GO TO THE >> > CASE OF GRAVITY WITHOUT ANY EM SOURCE FIELDS, AND WE STILL GET EM >> > RADIATION DUE TO THE ACCELERATION, WHERE DOES IT COME FROM? AG >> > >> It comes from the self-force, see here: >> >> https://arxiv.org/abs/0905.2391 >> >> Saibal >> > > In the case of GR, assuming no external EM sources, we still get > (according to resident experts) radiation emitted for accelerating charges. > So the claim of the article must be true; that the energy comes from the > field created by the accelerating charge. But wouldn't that imply the > charge of said particle must decrease to account for the reduced > self-field? > > > The energy comes from the field that accelerates the charge, i.e. the > gravitational potential. The photons radiated away carry energy, but not > charge. > > Brent > > That makes sense. Then, do you agree the article posted above is incorrect, or am I missing something here? AG
> Yet I don't believe that is claimed, so the result of the article is > baffling. AG > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > To post to this group, send email to [email protected] > <javascript:>. > Visit this group at https://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
