According to 1905 Relativity, a single material point must be always at rest
in [Relativity]
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From: valls on 8 Jun 2010 11:25 On 7 jun, 16:07, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > On Jun 7, 2:44 pm, va...(a)icmf.inf.cu wrote: > > > > > > > On 7 jun, 10:46, harald <h...(a)swissonline.ch> wrote: > > > > On Jun 7, 1:54 pm, va...(a)icmf.inf.cu wrote: > > > > > On 4 jun, 17:03, "Dono." <sa...(a)comcast.net> wrote:> On Jun 3, 1:02 pm, va...(a)icmf.inf.cu wrote: > > > > > > > Calculate then how slow is moving the clock at the pole with respect > > > > > > to the one at the equator (using what you believe is 1905 Relativity). > > > > > > Listen, imbecile > > > > > > We have known for about 95 years that all clocks on the geoid tick at > > > > > the same exact rate. > > > > > Yes, 2010-95=1915. We know by first time about clocks being affected > > > > by gravity using General Relativity. But we are addressing a 30Jun1905 > > > > Einsteins paper wrote about 10 years before, even about 3 months > > > > before the discovery of the universal mass-energy relationship in his > > > > 27Sep1905 paper. Then, when interpreting a 1905 paper you must not > > > > take into account the effect of gravity in the clocks, only the effect > > > > of speed. For 1905 Einstein, the moving clock at the equator is > > > > running slower than the rest one at the pole (under otherwise > > > > identical conditions, the literal last words at the end of paragraph > > > > 4 in the 30Jun1905 paper), a prediction confirmed today by the huge > > > > experimental evidence of today GPS. That the clock at the pole is NOT > > > > running slower than the one at the equator (owed to the speed effect) > > > > is also confirmed by the same huge experimental evidence. GPS > > > > engineers only maintain silent with a funny smile to us if we remember > > > > them that Special Relativity requires also a pole clock running slower > > > > that the equator one.> > I will add it to your personal list of (totally impossible) tasks. > > > > > > Not taking into account the experimental evidence, almost sure will > > > > > > always maintain you in the wrong road. > > > > > > How about if you read the NIST website on the subject, old fart? > > > > > Surely I will not find in it any information at all about how to > > > > correct interpret and old text respecting the historic context. The > > > > today knowledge about the clocks at the equator and at the pole > > > > running at the same rate owed to the combined effect of gravitation > > > > and speed, doesnt put false the 1905 knowledge about the clock at the > > > > equator running slower than the one at the pole owed to the effect of > > > > speed (ignoring the yet unknown gravitation effect). > > > > > RVHG (Rafael Valls Hidalgo-Gato) > > > > Indeed, for a perfectly homogeneous and spherical planet his > > > prediction is probably accurate. > > > > And if you want to know how it was "at once apparent" for Einstein > > > that a clock with a polygonal trajectory will be equally slow as one > > > with a straight trajectory, I can try to elaborate on his > > > explanation. > > > 1905 Einstein is simply assuming that the result obtained by him for a > > moving system with a uniform velocity v with respect to the stationary > > system (see the title of paragraph 3 in his 30Jun1905 paper), can be > > applied to an entity moving with ANY instantaneous velocity v using > > the procedures of integral and differential calculus (and without any > > previous mention to it!). See how the polygonal line is converted > > later in a continuous curved one. All this is more than sufficient to > > declare his work not well founded. > > ============= > > > Why then 1905 Einsteins work > > survived? > > Because it is quite profitable to collect tuition > for tensor calculus while hiring teachers of > Pythagoras. :-( > > > By the unique and very surprising fact that his predictions > > resulted supported by a huge experimental evidence! In today GPS > > system, the correction of a satellite clock owed to the not exact > > circularity of its orbit (and the corresponding not exact uniform > > speed) is done following 1905 Einstein! > > It seems not. > Living reviews in Relativity: 0 hits for query "on the > electrodynamics"http://relativity.livingreviews.org/Articles/lrr-2003-1/refs.html > I obtained the information in the same place you refer. In chapter 5 of the following paper you can see how the term (1/2)v^2 (first introduced by 1905 Einstein) is used, where v is the variable satellite speed: Ashby, N., Relativity in the Global Positioning System http://relativity.livingreviews.org/Articles/lrr-2003-1/ > Sue... > RVHG (Rafael Valls Hidalgo-Gato)
From: valls on 8 Jun 2010 11:55 On 7 jun, 16:48, harald <h...(a)swissonline.ch> wrote: > On Jun 7, 8:44 pm, va...(a)icmf.inf.cu wrote: > > > > > > > On 7 jun, 10:46, harald <h...(a)swissonline.ch> wrote: > > > > On Jun 7, 1:54 pm, va...(a)icmf.inf.cu wrote: > > > > > On 4 jun, 17:03, "Dono." <sa...(a)comcast.net> wrote:> On Jun 3, 1:02 pm, va...(a)icmf.inf.cu wrote: > > > > > > > Calculate then how slow is moving the clock at the pole with respect > > > > > > to the one at the equator (using what you believe is 1905 Relativity). > > > > > > Listen, imbecile > > > > > > We have known for about 95 years that all clocks on the geoid tick at > > > > > the same exact rate. > > > > > Yes, 2010-95=1915. We know by first time about clocks being affected > > > > by gravity using General Relativity. But we are addressing a 30Jun1905 > > > > Einsteins paper wrote about 10 years before, even about 3 months > > > > before the discovery of the universal mass-energy relationship in his > > > > 27Sep1905 paper. Then, when interpreting a 1905 paper you must not > > > > take into account the effect of gravity in the clocks, only the effect > > > > of speed. For 1905 Einstein, the moving clock at the equator is > > > > running slower than the rest one at the pole (under otherwise > > > > identical conditions, the literal last words at the end of paragraph > > > > 4 in the 30Jun1905 paper), a prediction confirmed today by the huge > > > > experimental evidence of today GPS. That the clock at the pole is NOT > > > > running slower than the one at the equator (owed to the speed effect) > > > > is also confirmed by the same huge experimental evidence. GPS > > > > engineers only maintain silent with a funny smile to us if we remember > > > > them that Special Relativity requires also a pole clock running slower > > > > that the equator one.> > I will add it to your personal list of (totally impossible) tasks. > > > > > > Not taking into account the experimental evidence, almost sure will > > > > > > always maintain you in the wrong road. > > > > > > How about if you read the NIST website on the subject, old fart? > > > > > Surely I will not find in it any information at all about how to > > > > correct interpret and old text respecting the historic context. The > > > > today knowledge about the clocks at the equator and at the pole > > > > running at the same rate owed to the combined effect of gravitation > > > > and speed, doesnt put false the 1905 knowledge about the clock at the > > > > equator running slower than the one at the pole owed to the effect of > > > > speed (ignoring the yet unknown gravitation effect). > > > > > RVHG (Rafael Valls Hidalgo-Gato) > > > > Indeed, for a perfectly homogeneous and spherical planet his > > > prediction is probably accurate. > > > > And if you want to know how it was "at once apparent" for Einstein > > > that a clock with a polygonal trajectory will be equally slow as > > > one with a straight trajectory, I can try to elaborate on his > > > explanation. > > > 1905 Einstein is simply assuming that the result obtained by him for > > a moving system with a uniform velocity v with respect to the stationary > > system (see the title of paragraph 3 in his 30Jun1905 paper), can be > > applied to an entity moving with ANY instantaneous velocity v using > > the procedures of integral and differential calculus (and without any > > previous mention to it!). See how the polygonal line is converted > > later in a continuous curved one. All this is more than sufficient to > > declare his work not well founded. > > In other words: instead of being curious what it was that Einstein > immediately saw and assumed that everyone would understand, you simply > assume that based on wrong thinking he found the right answer by luck! > As you know well, I had being curious for many years (and continue being) to all related with 1905 Einstein scientific work, always assuming profound non-evident hidden reasons in his thought. But that doesnt mean that I accepted as correct all what he writes. In the case we are addressing (the polygonal line converted later in a continuous curved one), I had being unable to find a satisfactory to me explanation about its correctness, being that the cause of my recent comment about it. > What do you think was immediately clear to Einstein, but faulty > thinking? And if it was faulty, why was his conclusion correct? > The intuition in science creation is a very difficult topic to talk about. Whatever the case about the correctness of the 1905 Einsteins derivation we are addressing and my inability to understand it (until now), I include it already in my interpretation of the 1905 text. As the experimental evidence supports it, I have no other alternative. > > Why then 1905 Einsteins work > > survived? By the unique and very surprising fact that his predictions > > resulted supported by a huge experimental evidence! In today GPS > > system, the correction of a satellite clock owed to the not exact > > circularity of its orbit (and the corresponding not exact uniform > > speed) is done following 1905 Einstein! > > No, that is wrong: GPS corrections include gravitational potential > which Einstein-1905 doesn't include. > When mentioning 1905 Einstein in a time relativity correction, it is clear that I am referring only to the part owed to speed. The effect of gravitation on clocks is first discovered by 1916 Einstein, having then no sense at all to talk about a gravitational potential correction in 1905. That 1905 Einstein doesnt include it is the unique valid alternative. In a similar way, when I say that the 1905 Einsteins prediction (about the clock at the equator running slower that the one at the pole) is confirmed experimentally, I am referring only to the speed effect, not taking into account the gravitational potential one. By the way, I derived already (since many years ago) the gravitational potential effect using only 1905 Relativity (that is, respecting the 1905 knowledge context). You can find it (in all detail) in my past talking with PD in this same thread. The new for you is that I also derive the shift of Mercurys perihelion using only 1905 Relativity, using some result that is hidden in the title of this thread (it is also already explicit in my talking with Sue in this same thread). Anyway, I will put it now: Rest mass and inertial mass is one and the same thing. > Harald RVHG (Rafael Valls Hidalgo-Gato)
From: valls on 8 Jun 2010 12:06 On 7 jun, 18:50, "Inertial" <relativ...(a)rest.com> wrote: > <va...(a)icmf.inf.cu> wrote in message > > news:c388c69e-947a-40ef-a82b-6bc675a157ea(a)e5g2000yqn.googlegroups.com... > > > > > > > On 7 jun, 10:46, harald <h...(a)swissonline.ch> wrote: > >> On Jun 7, 1:54 pm, va...(a)icmf.inf.cu wrote: > > >> > On 4 jun, 17:03, "Dono." <sa...(a)comcast.net> wrote:> On Jun 3, 1:02 pm, > >> > va...(a)icmf.inf.cu wrote: > > >> > > > Calculate then how slow is moving the clock at the pole with > >> > > > respect > >> > > > to the one at the equator (using what you believe is 1905 > >> > > > Relativity). > > >> > > Listen, imbecile > > >> > > We have known for about 95 years that all clocks on the geoid tick at > >> > > the same exact rate. > > >> > Yes, 2010-95=1915. We know by first time about clocks being affected > >> > by gravity using General Relativity. But we are addressing a 30Jun1905 > >> > Einsteins paper wrote about 10 years before, even about 3 months > >> > before the discovery of the universal mass-energy relationship in his > >> > 27Sep1905 paper. Then, when interpreting a 1905 paper you must not > >> > take into account the effect of gravity in the clocks, only the effect > >> > of speed. For 1905 Einstein, the moving clock at the equator is > >> > running slower than the rest one at the pole (under otherwise > >> > identical conditions, the literal last words at the end of paragraph > >> > 4 in the 30Jun1905 paper), a prediction confirmed today by the huge > >> > experimental evidence of today GPS. That the clock at the pole is NOT > >> > running slower than the one at the equator (owed to the speed effect) > >> > is also confirmed by the same huge experimental evidence. GPS > >> > engineers only maintain silent with a funny smile to us if we remember > >> > them that Special Relativity requires also a pole clock running slower > >> > that the equator one.> > I will add it to your personal list of > >> > (totally impossible) tasks. > >> > > > Not taking into account the experimental evidence, almost sure will > >> > > > always maintain you in the wrong road. > > >> > > How about if you read the NIST website on the subject, old fart? > > >> > Surely I will not find in it any information at all about how to > >> > correct interpret and old text respecting the historic context. The > >> > today knowledge about the clocks at the equator and at the pole > >> > running at the same rate owed to the combined effect of gravitation > >> > and speed, doesnt put false the 1905 knowledge about the clock at the > >> > equator running slower than the one at the pole owed to the effect of > >> > speed (ignoring the yet unknown gravitation effect). > > >> > RVHG (Rafael Valls Hidalgo-Gato) > > >> Indeed, for a perfectly homogeneous and spherical planet his > >> prediction is probably accurate. > > >> And if you want to know how it was "at once apparent" for Einstein > >> that a clock with a polygonal trajectory will be equally slow as one > >> with a straight trajectory, I can try to elaborate on his > >> explanation. > > > 1905 Einstein is simply assuming that the result obtained by him for a > > moving system with a uniform velocity v with respect to the stationary > > system (see the title of paragraph 3 in his 30Jun1905 paper), can be > > applied to an entity moving with ANY instantaneous velocity v using > > the procedures of integral and differential calculus (and without any > > previous mention to it!). See how the polygonal line is converted > > later in a continuous curved one. All this is more than sufficient to > > declare his work not well founded. Why then 1905 Einsteins work > > survived? By the unique and very surprising fact that his predictions > > resulted supported by a huge experimental evidence! In today GPS > > system, the correction of a satellite clock owed to the not exact > > circularity of its orbit (and the corresponding not exact uniform > > speed) is done following 1905 Einstein! > > Clearly .. as the work done up to and including 1905 Einstein does NOT > explain GPS corrections. So it must be the work that followed it. > 1905 Einstein DOES EXPLAIN the owed to speed part of the GPS correction. > 1905 Paper is a good starting point, and presents the essence of SR > (although it is better presented using minkowski geometry etc, its still > essentially the same notion), and it led to the development of GR. RVHG (Rafael Valls Hidalgo-Gato)
From: Inertial on 8 Jun 2010 12:16 <valls(a)icmf.inf.cu> wrote in message news:7dce699d-02f4-4080-99f4-10306dcaf4c4(a)g19g2000yqc.googlegroups.com... > On 7 jun, 18:50, "Inertial" <relativ...(a)rest.com> wrote: >> <va...(a)icmf.inf.cu> wrote in message >> >> news:c388c69e-947a-40ef-a82b-6bc675a157ea(a)e5g2000yqn.googlegroups.com... >> >> >> >> >> >> > On 7 jun, 10:46, harald <h...(a)swissonline.ch> wrote: >> >> On Jun 7, 1:54 pm, va...(a)icmf.inf.cu wrote: >> >> >> > On 4 jun, 17:03, "Dono." <sa...(a)comcast.net> wrote:> On Jun 3, 1:02 >> >> > pm, >> >> > va...(a)icmf.inf.cu wrote: >> >> >> > > > Calculate then how slow is moving the clock at the pole with >> >> > > > respect >> >> > > > to the one at the equator (using what you believe is 1905 >> >> > > > Relativity). >> >> >> > > Listen, imbecile >> >> >> > > We have known for about 95 years that all clocks on the geoid tick >> >> > > at >> >> > > the same exact rate. >> >> >> > Yes, 2010-95=1915. We know by first time about clocks being affected >> >> > by gravity using General Relativity. But we are addressing a >> >> > 30Jun1905 >> >> > Einstein�s paper wrote about 10 years before, even about 3 months >> >> > before the discovery of the universal mass-energy relationship in >> >> > his >> >> > 27Sep1905 paper. Then, when interpreting a 1905 paper you must not >> >> > take into account the effect of gravity in the clocks, only the >> >> > effect >> >> > of speed. For 1905 Einstein, the moving clock at the equator is >> >> > running slower than the rest one at the pole (�under otherwise >> >> > identical conditions�, the literal last words at the end of >> >> > paragraph >> >> > 4 in the 30Jun1905 paper), a prediction confirmed today by the huge >> >> > experimental evidence of today GPS. That the clock at the pole is >> >> > NOT >> >> > running slower than the one at the equator (owed to the speed >> >> > effect) >> >> > is also confirmed by the same huge experimental evidence. GPS >> >> > engineers only maintain silent with a funny smile to us if we >> >> > remember >> >> > them that Special Relativity requires also a pole clock running >> >> > slower >> >> > that the equator one.> > I will add it to your personal list of >> >> > (totally impossible) tasks. >> >> > > > Not taking into account the experimental evidence, almost sure >> >> > > > will >> >> > > > always maintain you in the wrong road. >> >> >> > > How about if you read the NIST website on the subject, old fart? >> >> >> > Surely I will not find in it any information at all about how to >> >> > correct interpret and old text respecting the historic context. The >> >> > today knowledge about the clocks at the equator and at the pole >> >> > running at the same rate owed to the combined effect of gravitation >> >> > and speed, doesn�t put false the 1905 knowledge about the clock at >> >> > the >> >> > equator running slower than the one at the pole owed to the effect >> >> > of >> >> > speed (ignoring the yet unknown gravitation effect). >> >> >> > RVHG (Rafael Valls Hidalgo-Gato) >> >> >> Indeed, for a perfectly homogeneous and spherical planet his >> >> prediction is probably accurate. >> >> >> And if you want to know how it was "at once apparent" for Einstein >> >> that a clock with a polygonal trajectory will be equally slow as one >> >> with a straight trajectory, I can try to elaborate on his >> >> explanation. >> >> > 1905 Einstein is simply assuming that the result obtained by him for a >> > moving system with a uniform velocity v with respect to the stationary >> > system (see the title of paragraph 3 in his 30Jun1905 paper), can be >> > applied to an entity moving with ANY instantaneous velocity v using >> > the procedures of integral and differential calculus (and without any >> > previous mention to it!). See how the polygonal line is converted >> > later in a continuous curved one. All this is more than sufficient to >> > declare his work not well founded. Why then 1905 Einstein�s work >> > survived? By the unique and very surprising fact that his predictions >> > resulted supported by a huge experimental evidence! In today GPS >> > system, the correction of a satellite clock owed to the not exact >> > circularity of its orbit (and the corresponding not exact uniform >> > speed) is done following 1905 Einstein! >> >> Clearly .. as the work done up to and including 1905 Einstein does NOT >> explain GPS corrections. So it must be the work that followed it. >> > 1905 Einstein DOES EXPLAIN the owed to speed part of the GPS > correction. Not what you said. And the speed effect is opposite to, and less than the effect due to difference in gravitational potential. SR in the 1905 paper provided a starting point or the more inclusive GR that DOES explain the GPS corrections more fully and correctly. There are better examples of experiments and equipment that exhibit predominantly 1905-SR effects >> 1905 Paper is a good starting point, and presents the essence of SR >> (although it is better presented using minkowski geometry etc, its still >> essentially the same notion), and it led to the development of GR. > > RVHG (Rafael Valls Hidalgo-Gato)
From: harald on 8 Jun 2010 12:29
On Jun 8, 5:55 pm, va...(a)icmf.inf.cu wrote: > On 7 jun, 16:48, harald <h...(a)swissonline.ch> wrote: > > > On Jun 7, 8:44 pm, va...(a)icmf.inf.cu wrote: > > > > On 7 jun, 10:46, harald <h...(a)swissonline.ch> wrote: > > > > > On Jun 7, 1:54 pm, va...(a)icmf.inf.cu wrote: > > > > > > On 4 jun, 17:03, "Dono." <sa...(a)comcast.net> wrote:> On Jun 3, 1:02 pm, va...(a)icmf.inf.cu wrote: > > > > > > > > Calculate then how slow is moving the clock at the pole with respect > > > > > > > to the one at the equator (using what you believe is 1905 Relativity). > > > > > > > Listen, imbecile > > > > > > > We have known for about 95 years that all clocks on the geoid tick at > > > > > > the same exact rate. > > > > > > Yes, 2010-95=1915. We know by first time about clocks being affected > > > > > by gravity using General Relativity. But we are addressing a 30Jun1905 > > > > > Einsteins paper wrote about 10 years before, even about 3 months > > > > > before the discovery of the universal mass-energy relationship in his > > > > > 27Sep1905 paper. Then, when interpreting a 1905 paper you must not > > > > > take into account the effect of gravity in the clocks, only the effect > > > > > of speed. For 1905 Einstein, the moving clock at the equator is > > > > > running slower than the rest one at the pole (under otherwise > > > > > identical conditions, the literal last words at the end of paragraph > > > > > 4 in the 30Jun1905 paper), a prediction confirmed today by the huge > > > > > experimental evidence of today GPS. That the clock at the pole is NOT > > > > > running slower than the one at the equator (owed to the speed effect) > > > > > is also confirmed by the same huge experimental evidence. GPS > > > > > engineers only maintain silent with a funny smile to us if we remember > > > > > them that Special Relativity requires also a pole clock running slower > > > > > that the equator one.> > I will add it to your personal list of (totally impossible) tasks. > > > > > > > Not taking into account the experimental evidence, almost sure will > > > > > > > always maintain you in the wrong road. > > > > > > > How about if you read the NIST website on the subject, old fart? > > > > > > Surely I will not find in it any information at all about how to > > > > > correct interpret and old text respecting the historic context. The > > > > > today knowledge about the clocks at the equator and at the pole > > > > > running at the same rate owed to the combined effect of gravitation > > > > > and speed, doesnt put false the 1905 knowledge about the clock at the > > > > > equator running slower than the one at the pole owed to the effect of > > > > > speed (ignoring the yet unknown gravitation effect). > > > > > > RVHG (Rafael Valls Hidalgo-Gato) > > > > > Indeed, for a perfectly homogeneous and spherical planet his > > > > prediction is probably accurate. > > > > > And if you want to know how it was "at once apparent" for Einstein > > > > that a clock with a polygonal trajectory will be equally slow as > > > > one with a straight trajectory, I can try to elaborate on his > > > > explanation. > > > > 1905 Einstein is simply assuming that the result obtained by him for > > > a moving system with a uniform velocity v with respect to the stationary > > > system (see the title of paragraph 3 in his 30Jun1905 paper), can be > > > applied to an entity moving with ANY instantaneous velocity v using > > > the procedures of integral and differential calculus (and without any > > > previous mention to it!). See how the polygonal line is converted > > > later in a continuous curved one. All this is more than sufficient to > > > declare his work not well founded. > > > In other words: instead of being curious what it was that Einstein > > immediately saw and assumed that everyone would understand, you simply > > assume that based on wrong thinking he found the right answer by luck! > > As you know well, I had being curious for many years (and continue > being) to all related with 1905 Einstein scientific work, always > assuming profound non-evident hidden reasons in his thought. But that > doesnt mean that I accepted as correct all what he writes. In the > case we are addressing (the polygonal line converted later in a > continuous curved one), I had being unable to find a satisfactory to > me explanation about its correctness, being that the cause of my > recent comment about it. From what you write here below, apparently you don't have a logical explanation yourself; and still you claim that it was faulty. Then what exactly was faulty do you think, and why? I had to think a few minutes about it before concluding that it is indeed obviously correct! > > What do you think was immediately clear to Einstein, but faulty > > thinking? And if it was faulty, why was his conclusion correct? > > The intuition in science creation is a very difficult topic to talk > about. Whatever the case about the correctness of the 1905 Einsteins > derivation we are addressing and my inability to understand it (until > now), I include it already in my interpretation of the 1905 text. As > the experimental evidence supports it, I have no other alternative. > > Why then 1905 Einsteins work > > > survived? By the unique and very surprising fact that his predictions > > > resulted supported by a huge experimental evidence! In today GPS > > > system, the correction of a satellite clock owed to the not exact > > > circularity of its orbit (and the corresponding not exact uniform > > > speed) is done following 1905 Einstein! > > > No, that is wrong: GPS corrections include gravitational potential > > which Einstein-1905 doesn't include. > > When mentioning 1905 Einstein in a time relativity correction, it is > clear that I am referring only to the part owed to speed. OK, you simply overlooked that the non-circular orbit of today's GPS satellite doesn't only change its speed. ;-) > The effect > of gravitation on clocks is first discovered by 1916 Einstein, having > then no sense at all to talk about a gravitational potential > correction in 1905. That 1905 Einstein doesnt include it is the > unique valid alternative. > In a similar way, when I say that the 1905 Einsteins prediction > (about the clock at the equator running slower that the one at the > pole) is confirmed experimentally, I am referring only to the speed > effect, not taking into account the gravitational potential one. > By the way, I derived already (since many years ago) the gravitational > potential effect using only 1905 Relativity (that is, respecting the > 1905 knowledge context). That is well known; Einstein started almost immediately with the development of the influence of gravitational potential, as already discussed in his 1907 paper. > You can find it (in all detail) in my past > talking with PD in this same thread. > The new for you is that I also derive the shift of Mercurys > perihelion using only 1905 Relativity, using some result that is > hidden in the title of this thread (it is also already explicit in my > talking with Sue in this same thread). Anyway, I will put it now: > > Rest mass and inertial mass is one and the same thing. That depends on definition. For example, the inertial mass of a high energy electron is in common language very different from its mass at rest. Harald |