[General] Relativistic space, time and field

[John Duffield]

All:

 

I've come back after a week away, and caught up with my emails. There's some
excellent stuff there, thanks everybody. 

 

John W:

 

Your question left me puzzled. There aren't two different fields, one
electric, one magnetic. The electron has an electromagnetic field, and it is
what it is. Imagine you can look at it, and walk around it, studying it from
every angle. It has this "screw" nature, like Maxwell said, and like
Minkowski said, not totally unlike the gravitomagnetic field
<http://science.nasa.gov/science-news/science-at-nasa/2011/04may_epic/> ,
but in three dimensions, and a whole lot fiercer. Now imagine you back up
then move past it fast. That electromagnetic field doesn't change one iota
just because you changed your state of motion. It doesn't transform at all.


 

Regards

John D

 

From: General
[mailto:general-bounces+johnduffield=btconnect.com at lists.natureoflightandpar
ticles.org] On Behalf Of John Williamson
Sent: 26 October 2015 08:17
To: Nature of Light and Particles - General Discussion
<general at lists.natureoflightandparticles.org>
Cc: 'Joakim Pettersson' <joakimbits at gmail.com>; Nick Bailey
<nick at bailey-family.org.uk>; 'Anthony Booth' <abooth at ieee.org>; 'Ariane
Mandray' <ariane.mandray at wanadoo.fr>
Subject: [General] Relativistic space, time and field

 

Dear ladies and gentlemen,

 

I must apologise in advance if I appear a little cranky this morning. I have
been up since 2 am (it is now 7.30 am) I have been in work every day last
week, including Saturday and Sunday - certainly more than double my
"contracted" hours - actually, getting close to three times them (four times
is not possible- though my "workload model" suggest I am only a third loaded
and my managers are trying to give me even more to do).  I am pissed off,
have not managed to eat properly and feel physically a bit ill.

 

The intense work has had the advantage that I have caught up with most,
though not all, of my University work. I feel as though I have never left
the damn place, and am already tired - though 12 hours looms ahead. The
coming week promises - if anything to be even worse . I will try not to take
it out on you .. but this will not be circumspect .

 

I have the feeling that we are, collectively, not really getting into the
discussion which needs to be had to make proper progress. This is not for
lack of trying on my part - but I seem to be getting no reaction at all to
the new bits - and yet lots of requests for clarification on parts of
physics as it is already is. 

 

Ladies and gentlemen - I just cannot do this. I cannot provide a tutor
service for things that are simply well explained in text books. Let me try
a little experiment to clarify what I mean.

 

For example, there has been a lot of discussion about Einstien's Special
relativity. There has been lots of talk about rulers and clocks, not with
the maths so much as in sort of allegorical terms. Everyone seems to think
they know what they are talking about - but I do not get the impression that
many of us really "get it" at all. Sorry.

 

This is not to be rude to you all. I agree with Al that most of the people
writing TEXT books with the word "relativity" in the title do not "get"
relativity much beyond rulers, clocks and synchronising imaginary
"observers". This is probably because that is how they "learned" it
themselves. Wiki is at the same (low) level. If the writers of the usual
sources are not beyond this - what hope does a graduate of those teachers in
universities have of getting there? I should say - it is not my goal or role
to sort all this out - though that is where my effort seems to have been
going.  See how Christian, for one, has been savaged by the pack for merely
daring to suggest some theory and maths appalls me. 

 

The lack of (quite basisc) understanding of many workers in the field leads
to many smart workers- some called Alice and/or Bob, to be completely
wasting their time. As Al says, one can explain most of this simply with
classical field theory and a proper understanding of relativity (which is
automatically in classical field theory - so there you go).

 

Let me give you a specific example, though, from relativity as explained in
the slightly more advanced big books - and I would like you all to be honest
with yourself and share it with the group if you were ignorant of the simple
fact I am about to state before I brought it up. There is no shame in this:
it is how relativity is taught in my "university" for example - so it is
probably not your fault.

 

It is common knowledge (whether "true" in the sense that Al, Martin and I
have been talking about it or not), that rulers "shrink" in the direction of
the Lorentz transformation and clocks "go slow". I have been astonished that
there has even been discussion about this within this group - but there you
go. I do not want to talk about this further here, there has been enough
said, but instead take the whole discussion a little bit further

 

Now I already know several in the group will know what I am about to say to
be true (Martin and  Stephen). I suspect others may also have got it (John
D, Adam K, Nick - but be honest guys). I am pretty sure that this will be
news to most of you - though most delighted if I am wrong!

 

Although lengths transform ONLY along the velocity directions, fields
transform (relativistically) ONLY perpendicular to it. The question is
simple: did you "know" that?

 

To be clear in what I am saying: if the velocity is in the z direction.
Lengths transform relativistically in z and not in x and y. Fields transform
relativistically in Ex, Ey, Bx, and By AND  PRECISELY NOT in Bz and Ez.

 

Once again: did you know that before I told you? Do you agree?

 

Regards, John W.

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