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Article #16172

Re: Why does light bend under gravity?

#16172
From: critico
Date: Thu, 27 Mar 2008 18:33
78 lines
5702 bytes
On 16 mar, 20:22, BradGuth <bradg...@gmail.com> wrote:
> On Mar 11, 11:21 pm, Pentcho Valev <pva...@yahoo.com> wrote:
>
>
>
>
>
> > On Mar 11, 5:27 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote in
> > sci.physics:
>
> > > Tom wrote:
> > > > The speed of light varies depending on the strength of the
> > > > gravitational field. Einstein said that.
>
> > > He said that in 1911, early on the then-unfinished journey to General
> > > Relativity. GR itself does not really have this property -- the _LOCAL_
> > > speed of light is everywhere c. When measured over non-local paths the
> > > speed of light can vary, but there is no definite dependence on
> > > "strength of the gravitational field", it's rather that one must compute
> > > an integral over the path to obtain the theoretical value for such a
> > > speed measurement.
>
> > >         Yes, as one prolific idiot around here is fixated on,
> > >         in the APPROXIMATION of weak fields and restriction to
> > >         paths at fixed gravitational potential, for Newtonian
> > >         coordinates one can express the non-local COORDINATE
> > >         speed of light in terms of the gravitational potential.
> > >         In 1911 Einstein did not understand all the caveats
> > >         mentioned here, but certainly did by 1915; this idiot
> > >         still does not understand them.
>
> > The year is 1920 Roberts Roberts and Divine Albert still believes that
> > the speed of light "varies with position" in a gravitational field, as
> > Superior Brother Steve Carlip explains to you:
>
> >http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_o...
> > Superior Brother Steve Carlip: "Einstein went on to discover a more
> > general theory of relativity which explained gravity in terms of
> > curved spacetime, and he talked about the speed of light changing in
> > this new theory.  In the 1920 book "Relativity: the special andgeneral theory" he wrote: ". . . according to the general theory of
>
> > relativity, the law of the constancy of the velocity of light in
> > vacuo, which constitutes one of the two fundamental assumptions in the
> > special theory of relativity [. . .] cannot claim any unlimited
> > validity.  A curvature of rays of light can only take place when the
> > velocity of propagation of light varies with position."  Since
> > Einstein talks of velocity (a vector quantity: speed with direction)
> > rather than speed alone, it is not clear that he meant the speed will
> > change, but the reference to special relativity suggests that he did
> > mean so.  THIS INTERPRETATION IS PERFECTLY VALID AND MAKES GOOD
> > PHYSICAL SENSE, but a more modern interpretation is that the speed of
> > light is constant in general relativity."
>
> > In a sense, Superior Brother Steve Carlip is less dishonest (or more
> > naive) than you Roberts Roberts.
>
> > Pentcho Valev
> > pva...@yahoo.com
>
> Interesting, but why does light reflect off a mirror, or get refracted
> by an atmosphere?
>
> Perhaps photons do not actually bend, but merely interact with other
> matter, be it regular or dark matter.
> . - Brad Guth-

Bravo les artistes !  57 interventions et pas un mot en Français .
On est bien sur un groupe fr. n'est-ce pas ?
Alors, pour ceux qui ne maîtrisent pas l'englich, il est très
difficile de repérer les conneries, car il doit y en avoir un tas , of
course...
Sans rancune, mais avec un pointe d'mamertume.
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From: critico <pierre.rios@numericable.fr>
Newsgroups: sci.physics,sci.physics.relativity,sci.physics.particle,fr.sci.physique,sci.astro
Subject: Re: Why does light bend under gravity?
Date: Thu, 27 Mar 2008 11:33:15 -0700 (PDT)
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