🚀 go-pugleaf

On May 8, 7:02 pm, Steve Carlip wrote in sci.physics.relativity:
> david <david_lawrence_pe...@yahoo.com> wrote:
> > It would seem that even Newtonian mechanics predicts that light will
> > follow a curved path in the presence of a gravitational field.  If
> > that's not obvious, think about the following thought experiment.  If
> > we shoot a bullet perfectly horizontally from, say, six feet above the
> > ground, and simultaneously drop a stone from six feet above the
> > ground, we know that they will hit the ground at the same time. So
> > just consider what would happen if we were to shoot the bullet at the
> > speed of light;  it would still hit the ground at the same time as the
> > stone, according to Newtonian mechanics. So a particle of light should
> > do the same.
>
> That's right.  This deflection was first computed by Soldner in a paper
> published in 1803.
>
> [...]
>
> > So this leads to a couple of possibly troubling questions.  First of
> > all, why were physicists surprised by Einstein's prediction that the
> > path of light would bend in a gravitational field (after all, even
> > Newtonian mechanics predicts that it would)?  
>
> I don't think this was ever seen as being particularly surprising, though
> it's less obvious what to expect in a wave theory of light.  It's your
> second question that's the key:
>
> > But more importantly,
> > is there a difference between what would be predicted by the
> > differential equation as described in the above paragraph and what is
> > predicted by general relativity, and are experimental measurements of
> > the bending of light by the sun accurate enough to distinguish between
> > the two predictions?
>
> General relativity predicts a deflection that's twice the Newtonian amount.
> Current measurements use Very Long Baseline Interferometry to measure
> the deflection of radio waves from quasars, and are accurate to a tenth of
> a percent or better, so distinguishing the Newtonian and relativistic
> predictions is easy.
>
> Steve Carlip

Sooner or later, Honest Carlip, you and your brothers Einsteinians
will have to explain which prediction, the Newtonian or the
relativistic (giving "a deflection that's twice the Newtonian
amount"), is consistent with the gravitational redshift factor 1+V/c^2
experimentally confirmed by Pound and Rebka:

http://groups.google.com/group/fr.sci.physique/msg/449b66e152b76430

Pentcho Valev
pvalev@yahoo.com