XPost: sci.electronics.design   
   From: bill.sloman@ieee.org   
      
   On 11/02/2026 10:49 am, john larkin wrote:   
   > On 10 Feb 2026 21:58:30 GMT, ram@zedat.fu-berlin.de (Stefan Ram)   
   > wrote:   
   >   
   >> john larkin  wrote or quoted:   
   >>> Two gamma rays (zero mass total) can collide to produce a particle   
   >>> pair (which has mass.)   
   >>   
   >>   Let's call the momenta of the two photons p0 and p1.   
   >>   
   >>   We may assume p1 = -p0 as the two photons are moving towards   
   >>   each other from opposite directions. Let's call the momentum   
   >>   of the system of these two photons "p", then we have:   
   >>   
   >> p = p0 + p1 = p0 +( -p0 )= p0 - p0 = 0   
   >>   
   >>   . Let's call the energy of this pair "E" and its mass "m". From   
   >>   
   >> E^2 = m^2 + p^2   
   >>   
   >>   (in units with c=1) and   
   >>   
   >> p = 0   
   >>   
   >>   , we get,   
   >>   
   >> E^2 = m^2   
   >>   
   >>   for the pair. I.e., all its energy is mass. And this is the   
   >>   mass the particle pair has after the collision.   
   >>   
   >> Newsgroups: sci.electronics.design,sci.physics   
   >> Followup-To: sci.physics   
   >> Subject changed.   
   >>   
   >   
   > The gamma rays had no gravitational effect on the rest of the mass in   
   > the universe, up until the instant that they collided to form a   
   > particle pair. Then a gravitational object magically appeared.   
      
   That's probably wrong. Energy has mass and the gamma ray photon   
   spresumably had exactly the same gravitational effect as the particel   
   pair that they created.   
      
   > Does't that create a spherical, symmetric, expanding bubble of   
   > gravity?   
      
   It seems unlikely.   
      
   > I'm just an engineer, but I think this is real. People say it's not   
   > technically possible, or that the efffect is too small to worry about,   
   > or some other excuse for not saying that it could happen.   
      
   You probably need to know a bit more science before you can claim to be   
   an engineer.   
      
   > There is an electrical equivalent. A metal sphere could suddenly   
   > become charged, and it would create a symmetric e-field pulse that   
   > expands at the speed of light, like a wave, but it isn't   
   > electromagnetic.   
      
   Except that an metal sphere couldn't "suddenly become charged" you'd   
   have to move charged particles around to create that effect. Charge is   
   conserved.   
   >   
   > I guess that you can't make an antenna that radiates em waves   
   > symmetrically in all directions.   
      
   Guess work isn't all that interesting.   
      
   --   
   Bill Sloman, Sydney   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)