From: helbig@asclothestro.multivax.de   
      
   In article , Michael Moroney  writes:   
   > On 11/30/2022 2:19 AM, Phillip Helbig (undress to reply) wrote:   
   > > In article ,   
   > > Carl K  writes:   
   > >   
   > >> I used a new perfect (but simple) Newtonian physics engine to revers=   
   e a   
   > >> billiards break. The simulation surprised me. I expected it to re-fo=   
   rm a   
   > >> stationary triangle of balls and spit out the cue ball. It did not.   
   > >>   
   > >> This means that classical physics is non-deterministic and not pract=   
   ically   
   > >> reversible.   
   > >   
   > > It does not mean that it is non-deterministic.  Make a movie of the   
   > > billiard break and run it backwards: perfectly valid physics.  Classi=   
   cal   
   > > physics is reversible.   
   > >   
   > > That it is not reversible in practice is a different matter, but that   
   > > was known before the simulation.   
   >   
   > Is it chaotic in a way, that is, a tiny change in the backwards action   
   > causes a completely different outcome?   
      
   Right.  Even if one could specify the positions and velocities as well   
   as allowed by the uncertainty principle, after just twelve collisions   
   the uncertainty in a ball's position would be larger than the size of   
   the table.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)