From: ram@zedat.fu-berlin.de   
      
   helbig@asclothestro.multivax.de (Phillip Helbig (undress to reply)) writes:   
   >                  In general relativity there is an effect known as   
   >frame-dragging, or the Lense-Thirring effect, which has been observed.   
      
     This probably cannot be used to explain inertia because it   
     has different properties.   
      
     On december 25, I submitted a small snippet about the   
     Lense-Thirring effect to this newsgroup. I have still not   
     seen it appear in this newsgroup. Here it is again:   
      
   |A body falling towards a stream of matter is indeed pulled in   
   |the direction of its motion, but a body moving away from the   
   |stream is accelerated in a direction opposite to the motion   
   |of the stream! And a body at rest feels no influence from the   
   |motion of the stream at all.   
   "Gravity from the Ground up" (2003) - Bernard Schutz (1946/).   
      
   >Imagine a completely empty universe.  Would there still be inertia?   
      
     I'm not trained in this area, but, following remarks by other   
     more trained individuals I read in the Usenet, one can say:   
      
     Even a space time with no mass and no electromagnetic field   
     energy has a metric.   
      
     This metric determines the possible geodesics of light. And   
     the geodesics of light are not rotating.   
      
     So, there always is a metric, and this defines the meaning   
     of "non-rotating" and "rotating".   
      
     And does not inertia follow from Noether's laws? I read that   
     these laws tell us that there is a conserved quantity for   
     every symmetry. In an empty universe, there would be perfect   
     homogeneity in three directions (axes). So the momenta in all   
     three directions would be conserved. Isn't this conservation   
     of momentum what one calls inertia?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)