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Article #16169

Re: Why does light bend under gravity?

#16169
From: BradGuth
Date: Sun, 30 Mar 2008 03:38
91 lines
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On Mar 16, 4:39 pm, The Speaking Clock <harlequin...@live.co.uk>
wrote:
> On 17 Mar, 01:04, BradGuth <bradg...@gmail.com> wrote:
>
>
>
> > On Mar 16, 1:41 pm, The Speaking Clock <harlequin...@live.co.uk>
> > wrote:
>
> > > On 16 Mar, 20:30, BradGuth <bradg...@gmail.com> wrote:
>
> > > > On Mar 16, 9:14 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>
> > > > > The Speaking Clock wrote:
> > > > > > On 15 Mar, 08:57, Pentcho Valev <pva...@yahoo.com> wrote:
> > > > > >> [... his usual nonsense]
>
> > > > > > Would the speed of light be a non wiggly constant at the very edge of
> > > > > > the universe - bending around it?
>
> > > > > The speed of light is a constant, c, for any LOCAL measurement anywhere
> > > > > in the universe. I guess that includes "non wiggly". It also includes
> > > > > essentially all measurements of light speed here on earth. At least that
> > > > > is what GR predicts, and there are no observations that contradict it.
>
> > > > >         [Ignore Valev when he brings up Pound-Rebka and similar
> > > > >          experiments -- they do not measure speed.]
>
> > > > > But if you want to see light "bending around the universe" then that
> > > > > would certainly require a non-local path, and there's no solid
> > > > > prediction of the result (given the uncertainties in the physical
> > > > > situation you have in mind).
>
> > > > > It is rather difficult to perform a non-local measurement of the speed
> > > > > of light, but it has been done by sending radar waves across the solar
> > > > > system to reflect back from mars and venus. By measuring the round-trip
> > > > > delay repeatedly over several years, and fitting to the planetary
> > > > > orbits, one can deduce the round-trip speed of light for these paths.
> > > > > That speed varies, depending on how close to the sun the path passes;
> > > > > look up "Shapiro time delay". The results are in excellent agreement
> > > > > with the predictions of GR.
>
> > > > >         Some people claim this is due to the solar atmosphere.
> > > > >         They are wrong: by doing this for multiple wavelengths the
> > > > >         effect of the solar atmosphere can be identified, and is
> > > > >         found to be negligible. Of course it would be highly
> > > > >         unlikely that such a different effect could mimic the GR
> > > > >         dependence on path. Indeed, measurements using pulsars
> > > > >         agree with the GR predictions for paths that never go
> > > > >         inside earth's orbit, and we know what the solar
> > > > >         atmosphere is out here.
>
> > > > > Tom Roberts
>
> > > > But photons clearly represent mass, thus the solar atmosphere of
> > > > photons does offer mass for other passing photons to interact with.
> > > > . -BradGuth- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > My physics friend says - "what about the underlying noise of the
> > > universe caused by the discrete nature of the photon/s in time, and
> > > how does that contribute to the total 1/f energy of the universe?"
>
> > > And then he changed the subject because light speed and it's constant
> > > interacting with what he talked about is something to do with space
> > > travel and I'm a buddhist.  lol.  Although - this is just my surmise;)
>
> > Don't exclude anything unless you know for certain otherwise.
> > . - Brad Guth- Hide quoted text -
>
> > - Show quoted text -
>
> *nodding like the churchill dog*
>
> My physics friend also says that photons have a *theoretical* mass.
> Whatever that means.  To a buddhist - everything looks largely
> theoretical.  :)
>
> Physists don't agree on anything - not the shape of the universe,
> whether light has a constant, why it bends.  Ask a simple question -
> get a complex argument.  Ah well - as long as people have fun.  :)

This anti-think-tank of a Usenet from hell is a good example, of
supposedly smart folks not hardly in agreement on much of anything,
especially if such rocks their mainstream status quo good ship
LOLLIPOP.

I like the zero-mass dump-truck as representing a photon, that which
can haul a wee bit of mass.
. - Brad Guth
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From: BradGuth <bradguth@gmail.com>
Newsgroups: sci.physics,sci.physics.relativity,sci.physics.particle,fr.sci.physique,sci.astro
Subject: Re: Why does light bend under gravity?
Date: Sat, 29 Mar 2008 20:38:19 -0700 (PDT)
Organization: http://groups.google.com
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