Re: Relativity claims the corona is too thin to refract enough to curve starlight.

On Wed, 20 Nov 2024 2:43:16 +0000, rhertz wrote:

I'm a believer in the phenomenon of refraction to explain starlight
deflection and "gravitational lensing". I'm totally against the crap
of GR and curved spacetime. This, for the record.

In discussing possible refraction effects affecting experimental
observations of gravitational deflection by the Sun, we need to
distinguish between VBLI observations made at radio wavelengths versus
observations made at optical wavelengths.
At radio wavelengths, refraction by the solar atmosphere is a known
issue. This refraction is dependent on frequency according to the
following formula: n = sqrt(1 - ω_p^2 / ω^2 ) where ω_p is the plasma
frequency, which is dependent on the electron density at the time of
observation.
VLBI observations of quasars like 3C279 are performed at multiple
wavelengths to allow highly accurate correction for this refraction,
which in any event is negligible beyond 3 degrees from the Sun.
https://iopscience.iop.org/article/10.1088/0004-637X/699/2/1395/pdf
Optical frequencies are unaffected by plasma refraction. Any bending
of light due to refraction would be from a different source.
At optical wavelengths, refraction is due to atoms or molecules
acting as polarizable dipoles. Incoming electromagnetic waves shift
their electrons back and forth. The dipoles absorb incoming light and
re-radiate light at the same frequency. Since the resonant frequency
of the dipoles does not match that of the incoming light, the
re-radiated light will be of slightly retarded phase relative to the
incoming light. The net result of all of this to slow the speed of
the wave passing through the medium. (This is assuming that the
frequency is not near an absorbance line, which results in anomalous
dispersion).
In the case of the Sun's atmosphere, above a transition zone a few
thousand kilometers above the surface, the coronal gases are heated
by as of yet poorly understood mechanisms to temperatures greater
than a million degrees. At these temperatures, all of the lighter
elements (hydrogen, helium, carbon, nitrogen, and oxygen) are
stripped of all their electrons, leaving bare nuclei. The few spectral
lines visible in the corona (above its bright continuous background)
are due to traces of iron, calcium, and other heavier elements which
manage to retain a few of their electrons.
The solar corona is therefore not only far too tenuous to account for
the observed deflection of starlight around the Sun, it is almost
totally devoid of polarizable species that can contribute to
refraction at optical wavelengths.