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   sci.physics.research      Current physics research. (Moderated)      17,516 messages   

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   Message 15,589 of 17,516   
   John Heath to Roland Franzius   
   Re: How to measure a Lorentz contraction   
   08 Mar 17 08:09:19   
   
   From: heathjohn2@gmail.com   
      
   On Sunday, March 5, 2017 at 2:55:56 AM UTC-5, Roland Franzius wrote:   
   > Am 03.03.2017 um 10:04 schrieb John Heath:   
   > > I like it. Simple and do-able. Should   
   > > be able to swing a 3 foot wire at 3 or   
   > > 4 Hz by hand with the hand end of the   
   > > wire clamped to a scope. I have spectrum   
   > > lab audio analyzer software on a lap top   
   > > for VLF whistlers , moving sky charges.   
   > > With this most of what is needed is already   
   > > in place. As you have already done this I   
   > > can proceed with confidence. One concern.   
   > > Standing in the middle of no where spinning   
   > > a 3 foot wire while looking at a lap top could   
   > > draw unwanted attention. I am tested for   
   > > a better WIFI connection officer , that's   
   > > my story and I am sticking to it.   
   > >   
   > > As to your dislike of the Lorentz contraction   
   > > interpretation of magnetism you are not alone.   
   > > I can say from my shoes it grows on you   
   > > over time. How often is there an opportunity   
   > > to toss a fundamental force in nature such   
   > > as magnetism straight into the trash bin?   
   > > One less to worry about.   
   > >   
   >   
   >   
   > Don't, because there are genuine electric and magnetic fields.   
   >   
   > The two quadratic forms E^2-B^2 and E.B are invariant with respect to   
   > Lorenz transformations. E.B=0 and |E|=|B| is mainly radiation.   
   >   
   > So there are static fields with |E|>|B| which are predominantly electric   
   > fields because you can find a system of reference with B'=0 and E' =   
   > E/sqrt(1-(v/c)^2).   
   > This system can be thought to be the rest system where you see charges   
   > at rest producing their common Coulomb field.   
   >   
   > And there are predominantly magnetic fields |B|>|E| where you can find a   
   > system reference with E'= 0 and B' = B/sqrt(1-(v/c)^2)   
   >   
   > Taken cum grano salis of course, because E,B are components of a rank 2   
   > tensor field, transforming with the product of two Lorentz tranformation   
   > matrices.   
   >   
   > An example of pure magnetic field with E=0 everywhere is the cylindrical=   
   >   
   > magnetic field B_phi =1/r around a finite conducting wire with with two   
   > equal constant currents: one of the negative charges to the left and   
   > positive charges to the right of identical current and charge density.   
   >   
   > So as an experiment, move at constant speed with your synchronized   
   > clocks/meterstick/ampere-meter/volt-meter equipment along a wire with   
   > the half velocity v/2 of the electron current.   
   >   
   > Now you have two equal currents of negative electrons and positive ions   
   > with equal but opposite velocities +-v/2.   
   >   
   > The wire is assumed somehow to be electrical neutral in the rest system   
   > of the ions.   
   >   
   > Of course, there will be a small longitudinal electrical field E_z to   
   > drive the electric current against the resistivity and to supply by ExB   
   > the dissipation energy current density from the field outside into the   
   > wire.   
   >   
   > E_z and dissipation can be made very small or even zero for a   
   > superconductor. So we can neglect the dissipation problem in a first   
   > approximation.   
   >   
   > Now you have by the Lorenz formula   
   >   
   >   B'_phi = B_phi /Sqrt(1-(v/2c)^2)   
   >   
   > and   
   >   
   > E'_r = v/(2c) x B_phi / Sqrt(1-(v/2c)^2)   
   >   
   > which means that in this system the current is larger and the wire is   
   > not neutral but - as an ideal conductor - carries some surface charge   
   > density  D_r that, by definition, is the value of D_r at the surface.   
   >   
   > How does this happen?   
   >   
   > Lorentz contraction contracts the longitudinal measured distance of the   
   > ions from rest at v=0 to v/2 using the simultaneity of the moving   
   > clocks.  By the same argument the distance of electrons is enlarged   
   > because their velocity is reduced from v to v/2. So the net charge   
   > density varies linearly with v.   
   >   
   > This fundamental effect arises at velocities as small as the current   
   > velocity of electrons of order 10^-11 lightseconds/second for a current   
   > of 1 A at a density of some 10^27 m^-3.   
   >   
   > The gigantic particle density of charges moving freely in metallic   
   > conductors makes these macroscopic effects easily detectable and   
   > measureable with high precision. This simple fact enabled Gau=DF, Faraday   
   > Maxwell and Einstein to find the laws of electrodynamics.   
   > These laws, applied by the gauge of the 4-momentum, imply Lorentz   
   > invariance of all physical laws.   
   >   
   > --   
   >   
   > Roland Franzius   
      
   Yes there is B=0 E=1 such as a Van De Graaff generator. There   
   is also B=1 E=0 such as a magnet. I will give an example in   
   applied physics where the same magnet is B=0 E=1.   
      
   This experiment requires a budget of 20 dollars plus a cleared   
   kitchen table. 1 old school small black and white TV set from   
   a thrift shop , 5 to 10 bucks , and a strong flat coin type   
   magnet from a hobby shop 10 to 15 bucks. We now have our   
   electron particle accelerator , TV , with a phosphor screen   
   to collect electron trajectory data. Electron velocity is in   
   the neighborhood of .1 c for a accelerating element of 10 KV   
   for this type of TV. Place the north end of the magnet facing   
   the TV screen. You will note the screen raster will turn   
   clockwise , Maxwell is right. Place the south pole and the   
   screen will turn counter clockwise , Maxwell is still right.   
   So far we have B=1 E=0. However if you look closely at the   
   magnet from the side you will see a black spot. A spot where   
   electrons with a velocity of .1 c are not hitting the phosphor?   
   Turning the magnet around will not help as there will still be   
   a black spot that electron do not care for. A Coulomb force to   
   cause this would have to be in the range of 15 KV to stop an   
   electron at .1 c in its tracks. That coulomb force is not in   
   Maxwell's equations. However it is in the Lorentz contraction   
   interpretation where effective movement of electrons only in   
   a magnet will result in a negative Coulomb force. This makes   
   it B=0 E=1 for a magnet.   
      
   Interesting though. If it were a anti matter magnet then it   
   would be the positrons that are effectively moving therefore   
   a strong positive Coulomb force. The black spot would now be   
   brighter than the rest of the screen. Now that I think of it   
   the screen plus a 10 city block radius around the screen would   
   light up. Maybe moving protons to make the positive magnet   
   would be better.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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