From: goldenfieldquaternions@gmail.com   
      
   On Wednesday, April 17, 2019 at 6:28:35 PM UTC-5, J.B. Wood wrote:   
   > Hello, all.  One concept that I can seem to get my thoughts around is   
   > that arguably gravitational force fits in to the Newtonian concept of a   
   > force that can act on a mass.  But general relativity informs us that   
   > gravity isn't a force at all but a phenomenon due to the curvature of   
   > space-time.  How can merely the curvature of space give rise to the fact   
   > that two untethered masses will tend to be attracted to and move toward   
   > one another?  We've seen those rubber-sheet demos but they rely on   
   > earth's gravity and we end up with a cause-effect-cause situation?   
   > Thanks for your time and comment.  Sincerely   
   > --   
   > J. B. Wood	            e-mail: arl_123234@hotmail.com   
      
   The curvature of spacetime due to mass-energy in a local region   
   will focus paths of particles in spacetime. The lines of longitude   
   meet each other at the poles, and in a somewhat analogous way the   
   spacetime paths of small particles in the curvature of spacetime   
   due to a central mass focus inwards. The one way of course a particle   
   can prevent itself from imploding inwards is to orbit.   
      
   LC   
      
   [[Mod. note -- I think the author is trying to say that   
   _on the Earth's surface_ lines of longitude (which are great circles,   
   and are thus "free-falling trajectories" on the surface) meet at the   
   poles.   
   -- jt]]   
      
   --- SoupGate-Win32 v1.05   
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