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Groups > sci.physics.relativity > #473070 > unrolled thread

Can two vectors define the Kerr metric?

Started bychemguy <rick_kingstone777@hotmail.com>
First post2018-09-25 13:29 -0700
Last post2018-10-06 11:07 +0000
Articles 6 on this page of 26 — 10 participants

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  Can two vectors define the Kerr metric? chemguy <rick_kingstone777@hotmail.com> - 2018-09-25 13:29 -0700
    Re: Can two vectors define the Kerr metric? JanPB <filmart@gmail.com> - 2018-09-25 13:39 -0700
      Re: Can two vectors define the Kerr metric? Hilton Packett <wod@wcothr.ce> - 2018-09-25 22:55 +0000
    Re: Can two vectors define the Kerr metric? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-09-25 23:58 +0200
      Re: Can two vectors define the Kerr metric? Tom Roberts <tjroberts137@sbcglobal.net> - 2018-09-26 10:16 -0500
        Re: Can two vectors define the Kerr metric? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-09-28 02:51 +0200
          Re: Can two vectors define the Kerr metric? Tom Roberts <tjroberts137@sbcglobal.net> - 2018-09-28 10:34 -0500
            Re: Can two vectors define the Kerr metric? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-09-28 18:55 +0200
              Re: Can two vectors define the Kerr metric? Tom Roberts <tjroberts137@sbcglobal.net> - 2018-09-29 08:32 -0500
                Re: Can two vectors define the Kerr metric? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-09-29 15:56 +0200
                  Re: Can two vectors define the Kerr metric? Tom Roberts <tjroberts137@sbcglobal.net> - 2018-09-30 16:09 -0500
                    Re: Can two vectors define the Kerr metric? Hilton Packett <wod@wcotahr.ce> - 2018-09-30 21:26 +0000
                Re: Can two vectors define the Kerr metric? passerby@domain.invalid - 2018-09-30 16:04 -0400
      Re: Can two vectors define the Kerr metric? JanPB <filmart@gmail.com> - 2018-09-28 16:09 -0700
    Re: Can two vectors define the Kerr metric? Tom Roberts <tjroberts137@sbcglobal.net> - 2018-09-26 10:11 -0500
    Re: Can two vectors define the Kerr metric? mitchrae3323@gmail.com - 2018-09-26 13:11 -0700
    Re: Can two vectors define the Kerr metric? Koobee Wublee <koobee.wublee@gmail.com> - 2018-10-03 12:53 -0700
      Re: Can two vectors define the Kerr metric? Paul Gish <uop@uwrwuao.tt> - 2018-10-03 20:16 +0000
      Re: Can two vectors define the Kerr metric? JanPB <filmart@gmail.com> - 2018-10-03 13:51 -0700
        Re: Can two vectors define the Kerr metric? Koobee Wublee <koobee.wublee@gmail.com> - 2018-10-03 14:24 -0700
          Re: Can two vectors define the Kerr metric? Paul Gish <uop@uwrwuao.tt> - 2018-10-03 21:36 +0000
          Re: Can two vectors define the Kerr metric? JanPB <filmart@gmail.com> - 2018-10-03 14:53 -0700
            Re: Can two vectors define the Kerr metric? Koobee Wublee <koobee.wublee@gmail.com> - 2018-10-03 15:03 -0700
            Re: Can two vectors define the Kerr metric? Paul Gish <uop@uwrwuao.tt> - 2018-10-04 17:30 +0000
              Re: Can two vectors define the Kerr metric? JanPB <filmart@gmail.com> - 2018-10-04 14:23 -0700
                Re: Can two vectors define the Kerr metric? Paul Gish <uop@uwrwuao.tt> - 2018-10-06 11:07 +0000

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#474021

FromPaul Gish <uop@uwrwuao.tt>
Date2018-10-03 21:36 +0000
Message-ID<pp3coi$hhf$3@gioia.aioe.org>
In reply to#474018
Koobee Wublee wrote:

> On Wednesday, October 3, 2018 at 1:51:48 PM UTC-7, JanPB wrote:
>> No, this is false.  All of the above is global analysis 101.
>> [Garbage snipped]
> 
> All this is geometry 1.  Any point is space or spacetime regardless how
> curved up it is can be described by a position vector.  This is a very
> simple concept of mapping the geometry of reality into observed space
> using the position vector <s> where in turn <s> can be described by the
> observer’s choice of coordinate system.  <shrug>

Mapping is the oldest trick in the book. As for instance using addition 
instead of multiplication.

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#474024

FromJanPB <filmart@gmail.com>
Date2018-10-03 14:53 -0700
Message-ID<816d2b36-de90-4a28-91ac-64873a6efd69@googlegroups.com>
In reply to#474018
On Wednesday, October 3, 2018 at 2:24:09 PM UTC-7, Koobee Wublee wrote:
> On Wednesday, October 3, 2018 at 1:51:48 PM UTC-7, JanPB wrote:
> > On Wednesday, October 3, 2018 at 12:53:22 PM UTC-7, Koobee Wublee wrote:
> 
> > > Say <s> is a position vector.  Then, d<s> or <ds> is a point vector
> > > that the self-styled physicists call tangent vector or something.
> > > <shrug>
> >
> > > Any geometry is the inner product of two d<s>.  For example,
> >
> > > **  ds² = d<s> * d<s> = [g]_ij d[q]^i d[q]^j
> >
> > > Where
> >
> > > **  ds = geometry of spacetime
> > > **  [g] = matrix that represents the metric
> > > **  [g]_ij = elements to [g]
> > > **  [q] = matrix that represents the coordinate system
> > > **  [q]^i, [q]^j = elements to [q]
> > > **  <?> * <?> = inner product of two vectors
> 
> > No, this is false.  All of the above is global analysis 101.
> >
> > [Garbage snipped]
> 
> All this is geometry 1.  Any point is space or spacetime regardless how curved up it is can be described by a position vector.

Incorrect.

--
Jan

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#474027

FromKoobee Wublee <koobee.wublee@gmail.com>
Date2018-10-03 15:03 -0700
Message-ID<37b7513c-c65a-4d74-ae55-926fc3efcee6@googlegroups.com>
In reply to#474024
On Wednesday, October 3, 2018 at 2:53:08 PM UTC-7, JanPB wrote:
> On Wednesday, October 3, 2018 at 2:24:09 PM UTC-7, Koobee Wublee wrote:

> > Any point is space or spacetime regardless how curved up it is can be
> > described by a position vector.  This is a very simple concept of
> > mapping the geometry of reality into observed space using the position
> > vector <s> where in turn <s> can be described by the observer’s choice
> > of coordinate system.  <shrug>
>
> > d<s> or <ds> is a point vector that the self-styled physicists call
> > tangent vector or something.  Any geometry is the inner product of two
> > d<s>.  For example,
>
> > **  ds² = d<s> * d<s> = [g]_ij d[q]^i d[q]^j
>
> > Where
>
> > **  ds = geometry of spacetime
> > **  [g] = matrix that represents the metric
> > **  [g]_ij = elements to [g]
> > **  [q] = matrix that represents the coordinate system
> > **  [q]^i, [q]^j = elements to [q]
> > **  <?> * <?> = inner product of two vectors

> Incorrect.

That is the opinion of the queer of England who never has comprehended geometry 1.  <shrug>

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#474093

FromPaul Gish <uop@uwrwuao.tt>
Date2018-10-04 17:30 +0000
Message-ID<pp5ind$51d$3@gioia.aioe.org>
In reply to#474024
JanPB wrote:

>> All this is geometry 1.  Any point is space or spacetime regardless how
>> curved up it is can be described by a position vector.
> 
> Incorrect.

Combined with the gradient, it can. Go back under your bridge.

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#474112

FromJanPB <filmart@gmail.com>
Date2018-10-04 14:23 -0700
Message-ID<9a287426-b464-41f1-84ec-e6a153f87867@googlegroups.com>
In reply to#474093
On Thursday, October 4, 2018 at 10:30:25 AM UTC-7, Paul Gish wrote:
> JanPB wrote:
> 
> >> All this is geometry 1.  Any point is space or spacetime regardless how
> >> curved up it is can be described by a position vector.
> > 
> > Incorrect.
> 
> Combined with the gradient, it can. Go back under your bridge.

Not even wrong.

--
Jan

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#474245

FromPaul Gish <uop@uwrwuao.tt>
Date2018-10-06 11:07 +0000
Message-ID<ppa518$1hmv$7@gioia.aioe.org>
In reply to#474112
JanPB wrote:

> On Thursday, October 4, 2018 at 10:30:25 AM UTC-7, Paul Gish wrote:
>> JanPB wrote:
>> 
>> >> All this is geometry 1.  Any point is space or spacetime regardless
>> >> how curved up it is can be described by a position vector.
>> > 
>> > Incorrect.
>> 
>> Combined with the gradient, it can. Go back under your bridge.
> 
> Not even wrong.

Piece of cake, packed into a tensor combined with the curvature deficit.

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