From: jl@glen--canyon.com   
      
   On Tue, 10 Feb 2026 10:30:18 +0000, Martin Brown   
   <'''newspam'''@nonad.co.uk> wrote:   
      
   >On 09/02/2026 17:48, john larkin wrote:   
   >> If I reply to posts from the pointy-ear guy, they go to sci.astro,   
   >> even though his posts are in sci.electronics.design.   
   >   
   >There is nothing odd about it at all. He has set followups to sci.astro   
   >which is now a hell hole where all the lunatic fringe nutters hang out.   
   >   
   >sci.astro.amateur and .moderated was created to separate the deranged   
   >nutters with their NEW THEROY (sic) OF THE UNIVERSE all in CAPS from   
   >people who wanted to talk about astronomy. It worked for a while too.   
   >   
   >Your Usenet client is doing *exactly* what it is supposed to do.   
   >   
   >> This is agent/eternal september.   
   >>   
   >> The issue was   
   >>   
   >>> 3. By contrast to light, gravitational waves are quadrupole waves that are   
   >>>    only emitted when the spacetime curvature changes in a non-spherically   
   >>>    symmetric way.  They are also emitted by objects and systems which do   
   not   
   >>>    emit light.   
   >>   
   >> Suppose that somewhere out in free space a cannonball somehow   
   >> appeared. Wouldn't that create a symmetric, spherical gravitational   
   >> wave?   
   >   
   >E = mc^2   
      
   Exactly. Mass/energy conversion is one way to create or destroy some   
   mass in my cannonball.   
      
   Once that is done, a g-field change extends radially at the speed of   
   light, and could be detected as it passes sensors.   
      
   If that is not a spherically symmetrical gravitational wave, what   
   should we call it?   
      
   >   
   >It is not possible to violate conservation of mass energy in the way   
   >that you propose with enough mass to have an appreciable gravitational   
   >effect. Quantum mechanics uncertainty principle puts very strict bounds   
   >on how much mass/energy you can spirit into existence and for how long.   
      
   Any nonzero effect, no matter how small, would still be real.   
      
      
   >   
   >The simplest system that can create gravitational waves is a close   
   >binary star system. Ones with two pulsars in are very handy tests of   
   >relativity. I was at the seminar where that discovery was announced.   
   >   
   >https://en.wikipedia.org/wiki/Hulse–Taylor_pulsar#Use_as_a_test   
   of_general_relativity   
   >   
   >https://en.wikipedia.org/wiki/PSR_J0737?3039   
   >   
   >LIGO sees them only in the very final stages of orbital when they go   
   >down the plug hole with a big crunch.   
   >   
   >> Microphones some distance away, in any direction, would hear a click   
   >> some time later.   
   >   
   >If you could do it and on a large enough scale then it would perturb the   
   >orbits of objects but only after enough time has elapsed for its   
   >influence to reach them (and it would switch on suddenly in a step).   
   >   
   >However, conservation of mass-energy prevents it from being possible.   
   >   
   >This was always the problem with Newtonian gravitation - to avoid having   
   >the Earth spiral into the sun in classical mechanics the speed of   
   >Newtonian gravity has to be infinite. IOW It has to be an exactly   
   >central force between the two centres of mass at every instant in time.   
   >   
   >GR gets around this by redefining what is a straight line so that the   
   >influence of the sun is handled by the curvature of spacetime itself.   
      
   My instant cannonball would obviously lose energy from pushing out its   
   spherical g-thing-that-must-not-be-named.   
      
      
   John Larkin   
   Highland Tech Glen Canyon Design Center   
   Lunatic Fringe Electronics   
      
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