XPost: sci.physics.relativity   
   From: nospam@de-ster.demon.nl   
      
   Paul.B.Andersen  wrote:   
      
   > Den 16.07.2025 07:06, skrev Bertitaylor:   
   > > On Mon, 23 Jun 2025 8:44:28 +0000, J. J. Lodder wrote:   
   > >   
   > >> David Canzi  wrote:   
   > >>   
   > >>>   
   > >>> Has anybody calculated how much refraction by the Sun's atmosphere   
   > >>> would bend a ray of star light, and was the result of that calculation   
   > >>> close to the observed bending?   
   >   
   > >>   
   > >> Yes, of course. Eddington and friends already did that.   
   > >> The answer is that there is no way of explaining the bending of   
   > >> starlight by refraction in the Sun's atmosphere.   
   > >> The density is far too low for that.   
   >   
   > >   
   > > No, the density near the surface must be much higher than air on Earth's   
   > > surface. Solar flares exist. They scatter mass all around. The   
   > > atmosphere around the Sun must stretch for hundreds of not thousands of   
   > > kilometres. Then there is the size of the Sun overall a very huge   
   > > optical lens.   
   >   
   > The radius of the solar corona is 8 million km.   
   > That is 7.3 million km outside of the Sun,   
   > much more than your "if not thousands of kilometres".   
   >   
   > But when the angle star-Sun is  ? > 3.2? the ray from   
   > the star that hits the Earth is never inside of the corona.   
   >   
   > The vast majority of the measured gravitational deflections   
   > are made at higher angles than that.   
   >   
   > https://paulba.no/paper/Shapiro_2004.pdf   
   > Measurements for  ? from 1? to 179?. (FIG. 1)   
   >   
   > https://paulba.no/paper/PPN_gamma_Hipparcos.pdf   
   > Measurement for  ? from 45? to 135?. (Figure 2.)   
   >   
   > The solar eclipse measurements where the ray goes through   
   > the corona are of historic interest only.   
      
   And for the kiddies: The corona is a plasma.   
   The index of refraction of a plasma is well understood.   
      
   It has a noticeable index of refraction at radio wavelengths.   
   (but the deflection of radio waves can be measured accurately   
   far away from the sun.   
   At optical wavelengths the index of refraction is negligeable,   
   even for light passing close to the sun,   
      
   Jan   
      
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