XPost: sci.math   
   From: relativity@paulba.no   
      
   Den 12.11.2025 09:13, skrev Thomas Heger:   
   > Am Dienstag000011, 11.11.2025 um 20:58 schrieb Paul.B.Andersen:   
   >>   
   >> No theory of physics can "describe what's really happening".   
   >> A theory of physics is a mathematical model of some aspects   
   >> of nature. The best it can do is to give correct predictions   
   >> of what will be measured or observed in some experiments.   
      
   > I do not agree.   
      
   So you claim that a theory of physics can  "describe what's   
   really happening"?   
      
   > I actually think, that models and reality are two distict entities.   
      
   As opposed to what I think?   
   > Models are useful, but nature is not.   
      
      
   A statement void of meaning   
   For what are "models" useful, and for what is "nature" not useful?   
      
   >   
   > Nature is as nature is and that is not supposed to serve our demands.   
      
      
   "Nature is not supposed to serve our demands."   
      
   Don't you understand that this is an idiotic statement?   
      
   >   
   > To make calculations possible we use simplyfied versions of the real   
   > world, call that 'model' and let them run in computers.   
   >   
   > But that is NOT how nature functions, not even close.   
   >   
   > If we want to understand nature, we had to give up our demands for   
   > usuable models, because we can safely assume, that nature itself does   
   > not use computers.   
      
   So you are claiming that to understand nature we must not   
   use theories of physics because nature itself doesn't use   
   computers.   
      
   And then we will "understand nature"? :-D   
      
   -----------------------   
      
   Now let's look at a meaningful statement:   
      
   No theory of physics can "describe what's really happening".   
   A theory of physics is a mathematical model of some aspects   
   of nature. The best it can do is to give correct predictions   
   of what will be measured or observed in some experiments.   
      
   This means that a theory of physics is _not_ "nature" or   
   "the reality". And we can never "understand nature".   
   Theories of physics are mathematical models.   
   We can understand these models.   
   And these models can actually help us designing mechanical   
   and electrical appliances and machinery.   
      
   The civilisation as we know it would be impossible without   
   these theories of physics.   
   (NM, Maxwell, thermodynamics, hydrodynamics, aerodynamics, SR, GR)   
      
   Do you agree?   
      
      
   >> What forces are acting on you right now?   
   >   
   > Coffein and peanut butter sandwiches.   
      
   Does that mean that you are unable to give a sensible response to   
   the following?   
      
   You. Thomas Heger wrote:   
   | Usually gravity is considered to be a force, which accelerates   
   | objects, once they are allowed to fall.   
   | This force reaches out from planet Earth with invisible hands   
   | and pulls down falling objects with a certain force.   
   | That is certainly not a valid description of what is really   
   | happening in gravity.   
   |   
   | Unfortunately nobody has a better one.   
      
   'The General Theory of Physics' (GR)   
     is a much better model of gravitation that NM.   
      
   So please respond to the following:   
      
   Now you take your accelerometer and enter the capsule.   
   The mass of the capsule with you in it is M.   
   But this time the capsule is accelerated by a rocket with   
   a force F so that F/M = 9.81 m/s².   
      
   Your accelerometer shows that your acceleration is 9.81 m/s².   
      
   Can you tell if you are stationary (relative to ground)   
   one meter above the ground, or are accelerating somewhere   
   out in space?   
      
      
   In GR, there is no gravitational force.   
   Gravitation is the curvature of spacetime.   
   Mass curve spacetime.   
   There is no 'action at the distance'.   
      
   The mass of the Earth curves spacetime, and satellites   
   do what the local curvature tell them to do.   
      
   Changes in masses (like orbiting Moon) will change the curvature   
   with the speed of light. No instant action at a distance.   
      
      
   --   
   Paul   
      
   https://paulba.no/   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)