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Re: This is your guru

From Steven Carlip <carlip@physics.ucdavis.edu>
Newsgroups sci.physics.relativity, sci.physics
Subject Re: This is your guru
Date 2016-11-23 10:46 -0800
Organization A noiseless patient Spider
Message-ID <o14o3d$ms7$1@dont-email.me> (permalink)
References (13 earlier) <o0v276$44d$1@gioia.aioe.org> <o10d8g$86o$1@dont-email.me> <o1179k$1f4h$1@gioia.aioe.org> <o13ekb$5vp$1@dont-email.me> <o1462n$3e7$1@gioia.aioe.org>

Cross-posted to 2 groups.

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On 11/23/16 5:37 AM, Dusty Kollman wrote:
> Steven Carlip wrote:

>> Gravity is a little more complicated -- it takes more than one number
>> ("how much light") to describe spacetime curvature, and there are
>> conservation laws that come in, so you get things like quadrupole
>> radiation and velocity-dependent effects.  But the basic idea is the
>> same.

[...]
> In spite of what you said is pretty much consistent, I'm not convinced. As
> you say, light shadows are not a one-to-one analogy. The point is that it
> is about the geometry/projection, not the shadow.

Good.  You shouldn't be convinced by an analogy -- you should just take
it as a starting point for learning more.

The simplest next step is electromagnetism rather than gravity.
There's a beautiful quantitative description of how the field of a
moving charge "separates" from the charge in Purcell, _Electricity
and Magnetism_, section 5.7.  This is very close to my description
of what happens with the shadow of a moving object, but it has all
of the details.

For gravity, as I said, it's more complicated, especially since the
field equations are nonlinear.  You can find a derivation of the
linear approximation in any GR textbook, and if you compare to
Purcell, you'll see that the description is very similar.  Once
you really understand this, it might be fun to do a more direct
analogue of Purcell's argument.  This should be possible by using
the Kinnersley metric (you can get a start by looking at my paper
at https://arxiv.org/abs/gr-qc/9909087).

Steve Carlip


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Thread

This is your guru mlwozniak@wp.pl - 2016-11-16 00:09 -0800
  Re: This is your guru Melzzzzz <mel@zzzzz.com> - 2016-11-16 10:52 +0100
    Re: This is your guru mlwozniak@wp.pl - 2016-11-16 02:41 -0800
      Re: This is your guru Melzzzzz <mel@zzzzz.com> - 2016-11-16 11:43 +0100
        Re: This is your guru mlwozniak@wp.pl - 2016-11-16 03:49 -0800
          Re: This is your guru Melzzzzz <mel@zzzzz.com> - 2016-11-16 13:18 +0100
            Re: This is your guru mlwozniak@wp.pl - 2016-11-16 04:48 -0800
              Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-16 21:54 -0800
                Re: This is your guru mlwozniak@wp.pl - 2016-11-16 23:19 -0800
                Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-16 23:32 -0800
                Re: This is your guru mlwozniak@wp.pl - 2016-11-16 23:38 -0800
                Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-17 00:14 -0800
                Re: This is your guru mlwozniak@wp.pl - 2016-11-17 00:38 -0800
                Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-17 10:37 -0800
                Re: This is your guru mlwozniak@wp.pl - 2016-11-17 22:36 -0800
    Re: This is your guru Tom Roberts <tjroberts137@sbcglobal.net> - 2016-11-16 10:26 -0600
      Re: This is your guru Kieth Staudt <KiethS@StaudtInstitute.info> - 2016-11-16 18:12 +0000
      Re: This is your guru Melzzzzz <mel@zzzzz.com> - 2016-11-16 19:28 +0100
      Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-16 21:57 -0800
        Re: This is your guru mlwozniak@wp.pl - 2016-11-16 23:34 -0800
          Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-17 00:23 -0800
            Re: This is your guru mlwozniak@wp.pl - 2016-11-17 03:37 -0800
              Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-17 10:39 -0800
                Re: This is your guru mlwozniak@wp.pl - 2016-11-17 22:50 -0800
                Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-17 23:52 -0800
                Re: This is your guru mlwozniak@wp.pl - 2016-11-18 00:53 -0800
                Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-18 12:28 -0800
                Re: This is your guru Maciej Woźniak <mlwozniak@wp.pl> - 2016-11-19 10:07 +0100
                Re: This is your guru Marion Vanriper <Marion@Vanriper.info> - 2016-11-26 09:30 +0000
        Re: This is your guru Tom Roberts <tjroberts137@sbcglobal.net> - 2016-11-17 10:09 -0600
  Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-16 12:11 -0800
    Re: This is your guru mlwozniak@wp.pl - 2016-11-16 23:14 -0800
      Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-16 23:35 -0800
        Re: This is your guru mlwozniak@wp.pl - 2016-11-16 23:52 -0800
          Re: This is your guru JanPB <filmart@gmail.com> - 2016-11-17 00:25 -0800
            Re: This is your guru paparios <paparios@gmail.com> - 2016-11-17 03:59 -0800
              Re: This is your guru "Dan S. MacAbre" <no@way.com> - 2016-11-17 12:12 +0000
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-18 05:07 +0100
                Re: This is your guru "Dan S. MacAbre" <no@way.com> - 2016-11-18 10:02 +0000
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-18 22:13 +0100
                Re: This is your guru "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-11-18 21:46 -0800
                Re: This is your guru "Paul B. Andersen" <relativity@paulba.no> - 2016-11-19 09:30 +0100
                Re: This is your guru Tom Roberts <tjroberts137@sbcglobal.net> - 2016-11-19 10:01 -0600
                Re: This is your guru "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-11-19 08:07 -0800
                Re: This is your guru Norberto Haman <norberman@norberman.info> - 2016-11-19 16:37 +0000
                Re: This is your guru Steven Carlip <carlip@physics.ucdavis.edu> - 2016-11-20 09:37 -0800
                Re: This is your guru Norberto Haman <norberman@norberman.info> - 2016-11-20 20:32 +0000
                Re: This is your guru Steven Carlip <carlip@physics.ucdavis.edu> - 2016-11-20 15:54 -0800
                Re: This is your guru Maryann Tonn <libradaz@libradazert.info> - 2016-11-21 15:00 +0000
                Re: This is your guru Steven Carlip <carlip@physics.ucdavis.edu> - 2016-11-21 19:16 -0800
                Re: This is your guru Maryann Tonn <libradaz@libradazert.info> - 2016-11-22 10:39 +0000
                Re: This is your guru paparios <paparios@gmail.com> - 2016-11-22 03:16 -0800
                Re: This is your guru Maryann Tonn <libradaz@libradazert.info> - 2016-11-22 11:24 +0000
                Re: This is your guru Ned Latham <nedlatham@woden.valhalla.oz> - 2016-11-22 12:13 +0000
                Re: This is your guru benj <benj@nobody.net> - 2016-11-22 17:37 -0500
                Re: This is your guru Steven Carlip <carlip@physics.ucdavis.edu> - 2016-11-22 22:57 -0800
                Re: This is your guru Dusty Kollman <uberdriver@uberdriver.info> - 2016-11-23 13:37 +0000
                Re: This is your guru paparios <paparios@gmail.com> - 2016-11-23 06:04 -0800
                Re: This is your guru Dusty Kollman <uberdriver@uberdriver.info> - 2016-11-23 14:27 +0000
                Re: This is your guru paparios <paparios@gmail.com> - 2016-11-23 06:44 -0800
                Re: This is your guru Dusty Kollman <uberdriver@uberdriver.info> - 2016-11-23 14:56 +0000
                Re: This is your guru Steven Carlip <carlip@physics.ucdavis.edu> - 2016-11-23 10:46 -0800
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-23 23:21 +0100
                Re: This is your guru Bob Goodman <bobg@boobgodman.info> - 2016-11-23 22:58 +0000
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-25 20:00 +0100
                Re: This is your guru Bernardo Dearmond <bnard@dearmond.org> - 2016-11-25 21:46 +0000
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-25 22:56 +0100
                Re: This is your guru "David (Lord Kronos) Fuller" <fuller.david@hotmail.com> - 2016-11-23 20:13 -0800
                Re: This is your guru Odd Bodkin <bodkinodd@gmail.com> - 2016-11-23 09:24 -0600
                Re: This is your guru Dusty Kollman <uberdriver@uberdriver.info> - 2016-11-23 15:33 +0000
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-23 23:23 +0100
                Re: This is your guru "David (Lord Kronos) Fuller" <fuller.david@hotmail.com> - 2016-11-23 20:15 -0800
                Re: This is your guru Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-11-25 20:05 +0100
                Re: This is your guru "David (Lord Kronos) Fuller" <fuller.david@hotmail.com> - 2016-11-25 14:57 -0800
                Re: This is your guru Dusty Kollman <uberdriver@uberdriver.info> - 2016-11-23 18:28 +0000
                Re: This is your guru Poutnik <poutnik4nntp@gmail.com> - 2016-11-23 19:37 +0100
                Re: This is your guru Dusty Kollman <uberdriver@uberdriver.info> - 2016-11-23 18:39 +0000
                Re: This is your guru "David (Lord Kronos) Fuller" <fuller.david@hotmail.com> - 2016-11-21 22:40 -0800
                Re: This is your guru Tom Roberts <tjroberts137@sbcglobal.net> - 2016-11-19 10:47 -0600
                Re: This is your guru Norberto Haman <norberman@norberman.info> - 2016-11-19 17:20 +0000
              Re: This is your guru mlwozniak@wp.pl - 2016-11-17 04:37 -0800

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