From: goldenfieldquaternions@gmail.com   
      
   On Saturday, August 18, 2018 at 6:35:11 AM UTC-5, Gregor Scholten wrote:   
   > Y Porat wrote:   
   >   
   > > now   
   > > did you ever  hear about the   
   > >   
   > >   
   > > ALL **PUSH THEORY ??   
   > > iow   
   > > at the 'end of the day ' it is always   
   > > push not pull !!   
   > > --   
   > > it took me just BTW   80 YEARS !!...thaT IS  my age ..   
   > > to understand for instance   
   > > how is our breathing is done ??!!:   
   > >   
   > > ONLY PUSH !! NOT never PULL !!!!!!..   
   >   
   > What's the difference? According to Newtonian equation of motion   
   >   
   > F = m a   
   >   
   > a force F makes a body undergo an acceleration a. One could say the   
   > force F "pulls" the body as well as the force "pushes" the body - there   
   > isn't any difference except in wording.   
   >   
   > In GR, a free-falling body is force-free, i.e. F = 0, it just follows   
   > its natural geodesic path in spacetime, so it is neither pulled nor   
   > pushed.   
   >   
   > When we say that gravity is attractive or that gravity pulls a body, we   
   > just describe the effect that two bodies that interact gravitationally   
   > tend to approach each other. In Newtonian theory, this means that the   
   > direction of the gravitational force on the one body points to the   
   > position of the other body, in GR, it means that the bodies influence   
   > the curvature of spacetime in that way that the geodesic lines which the   
   > bodies follow are bend towards each other.   
      
   I have found this question to be rather odd. I have not thought of   
   gravitation as either push or pull. In general relativity there is   
   no such thing as a force. There is only a force if there is some   
   material response that resists the geodesic deviated paths of   
   particles.   
      
   If one thinks of a Gaussian surface around a source of gravity that   
   is a black cloak the motion of particles is then due to mass-energy   
   inside. This has some appearance of a pull. However, once we pull   
   away the cloak we if we find a planet or star there is a force due   
   to material properties or pressure that is outwards. This would be   
   maybe a push.   
      
   A star is a nuclear fusion system and gravitation provides the   
   pressure in the core. Our attempts to get fusion in the lab involve   
   a pressure from the outside. The difficulties faced are Rayleigh-Taylor   
   instabilities. We then have a sense of the difference between the   
   maintenance of fusion by gravitation that is from the interior and   
   fusion in the lab that is induced by pressure from the outside.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)