🚀 go-pugleaf

On Feb 6, 2:57 pm, Albertito <albertito1...@gmail.com> wrote:
> On 6 feb, 19:15, Randy Poe <poespam-t...@yahoo.com> wrote:
>
>
>
> > On Feb 6, 2:00 pm, Albertito <albertito1...@gmail.com> wrote:
>
> > > On 6 feb, 18:54, Randy Poe <poespam-t...@yahoo.com> wrote:
>
> > > > On Feb 6, 12:39 pm, Albertito <albertito1...@gmail.com> wrote:
>
> > > > > On 6 feb, 16:48, "Androcles" <Headmas...@Hogwarts.physics> wrote:
>
> > > > > > <srp2...@gmail.com> wrote in message
>
> > > > > >news:4695358e-db97-4485-94b4-06f417a451d4@i7g2000prf.googlegroups.com...
> > > > > > On 6 fév, 02:34, Pentcho Valev <pva...@yahoo.com> wrote:
>
> > > > > > >http://philipball.blogspot.com/2007/09/arthur-eddington-was-innocent-...
> > > > > > > "With the technology then available, measuring the bending of
> > > > > > > starlight was very challenging. And contrary to popular belief,
> > > > > > > Newtonian physics did not predict that light would remain undeflected
> > > > > > > - Einstein himself pointed out in 1911 that Newtonian gravity should
> > > > > > > cause some deviation too. So the matter was not that of an all-or-
> > > > > > > nothing shift in stars' positions, but hinged on the exact numbers."
>
> > > > > > | Right.
>
> > > > > > | Classical Newtonian mechanics predicts that light will bend with
> > > > > > | twice the angle observed.
>
> > > > > > How?
>
> > > > > I'll tell you how. In order to see how newtonian gravity can
> > > > > bend the trajectory of a photon, relativists fake it. They
> > > > > magically tranform a photon with energy E into a particle
> > > > > with mass m = E/2c^2, it is saying  half the mass in E = mc^2.
> > > > > Then, relativists assume that particle passes by the massive
> > > > > body from infinity travelling locally at c, and then they can
> > > > > apply newtonian gravity to see how its trajectory is deflected
> > > > > into a hyperbolic one. As a result there is a deflection angle
> > > > > twice the observed one. A particle with mass m = E/c^2,
> > > > > travelling locally at c from infinity, would be deflected in
> > > > > the correct angle, under newtonian gravity.
>
> > > > Why don't you do the Newtonian calculation before
> > > > making this claim?
>
> > > >           - Randy
>
> > > The calculations have been already done by you relativists,http://www.theory.caltech.edu/people/patricia/obsertop.html
>
> > Correct.
>
> > > I'm only witness of that, and I see that if we double the mass
> > > assumed for a photon we attain the correct answer.
>
> > There are a great many assumptions in those
> > equations which you are not aware of. You are trying
> > to change the meaning of the symbols midstream.
>
> > Here's what those orbital mechanics equations look like for
> > planetary orbits:http://www.go.ednet.ns.ca/~larry/orbits/kepler.html
> > Note that E is the sum of kinetic energy and potential
> > energy. So what are you going to use for this E? Do
> > you really want to use mc^2 and claim it's a Newtonian
> > model?
>
> > If you were doing Newtonian gravitation the way Newton
> > did it to calculate the planetary orbits, you'd say
> > the kinetic energy is (1/2)*mc^2, and the potential
> > energy is -GMm/r. Then you'd find out that the mass m
> > drops out, that is the parameter E/m = [c^2/2 - GM/r]
> > does not depend on m.
>
> > Let's start from the basics: What is the initial velocity,
> > what is the acceleration, what is the result?
>
> > Start out with a velocity c, mass m, distance R
> > as it passes near mass M.
>
> > The acceleration experienced by the mass m is
> > GM/R^2. That is what you would apply to the velocity
> > vector to get the change in velocity. It does not
> > depend on m.
>
> > Trajectories of small bodies through solar systems do
> > not depend on mass.
>
>
> It's simpler than that. Under newtonian gravity you never
> can say that a photon is predicted to be deflected by twice
> the correct angle, because under newtonian gravity photons
> can't be addressed at all, only bodies with mass.

Right. Unless you assume it has mass, as people did
long before Einstein.

Once you do, the path is independent of whatever
mass you assume, just as any Newtonian path is.

> You never
> can fake a photon to behave as a particle with non-zero mass,
> that's unphysical. If you do fake a photon to behave so, then
> you attain a particle with mass travelling at c, which is impossible
> under your assumptions (i.e nothing with mass can travel at c).

What point are you trying to make? If the photon
truly has no mass (as we believe) then the Newtonian
model says it won't be deflected. Therefore gravitational
lensing won't happen.

Yet you seemed to be making a claim that there is
a Newtonian model that would predict light
bending. Presumably that would involve assuming
a nonzero mass.

So which model are you proposing? Is it
(a) the photon has no mass, so Newton says it
doesn't bend, or

(b) the photon has a mass, so Newton says it
bends (at half the GR prediction) independent
of mass?

You seemed to be proposing a third model which
was
(c) the photon has a mass, and unlike every other
calculation with Newtonian gravity, the trajectory
depends on mass.

Is that your claim? Stick to one model and we
can follow the consequences. Does the photon have
mass or not? Do you claim Newton predicts bending
or not?

          - Randy