XPost: sci.math   
   From: PointedEars@web.de   
      
   J. J. Lodder wrote:   
   > Thomas 'PointedEars' Lahn  wrote:   
   >> Paul B. Andersen wrote:   
   >>> Den 22.11.2025 20:19, skrev Thomas 'PointedEars' Lahn:   
   >>>> Scot Deyanov wrote:   
   >>>>> Thomas 'PointedEars' Lahn wrote:   
   >>>>>> A manipulated clock is not a clock.   
   >>>>>>   
   >>>>>> When we say that time is what is measured with a clock we mean a device   
   >>>>>> that is not manipulated, that merely follows Nature.   
   >>>>> no shit sherlock, once that manipulation is done, that clock is a clock   
   >>>>> like everybody clock   
   >>>> Which part of "_not_ manipulated" did you not understand?   
   >>>   
   >>> It is however common to call the manipulated clock   
   >>> in a GPS satellite - a clock.   
   >>   
   >> The satellite's clock is not manipulated; never has been.   
   >   
   > So you are clueless about that too.   
      
   You are the clueless one here.   
      
   > You really shouldn't make such categorical statements   
   > about things you know very litttle about.   
      
   Likewise.   
      
   > FYI, Satellite GPS clocks are steered to remain in sync   
   > with the master GPS clock at USNO.   
      
   No, they are NOT "steered"; they never were.  The beat frequency is not even   
   adjusted by a frequency synthesizer anymore (as it was with the NAVSTAR   
   NTS-1 test satellite in 1977), but the *beat* frequency (how many cycles are   
   counted as 1 second) is adjusted *once* (it is reduced according to GR)   
   *before* the clock is placed in orbit.  In addition, a correction value to   
   account for orbital variations is in included in the signal payload, as well   
   as ephemerides updates.   
      
   > (would have to look up the currently allowed tolerance)   
      
   You have a lot more to look up there.   
      
   I recommend to read this:   
      
   https://link.springer.com/article/10.12942/lrr-2003-1#Sec5   
      
   > FYA, an example of steering.   
   > The Big Ben clock in London has been kept in sync with true time   
   > (as taken from Greenwich Observatory)   
   > by means of a pile of pennies put on the pendulum weight,   
   > ever since it was put into motion about 150 years ago.   
   > If it is a second fast the caretaker removes a penny,   
   > if slow they put on another one.   
   > Of course this steering does not mean that Big Ben does not move   
   > in accordance with Newtonian mechanics.   
      
   By contrast to the clock of the Big Ben, GPS satellites use *atomic* clocks.   
    You cannot set or "steer" an atomic clock.  That is simply NOT how it works.   
      
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   PointedEars   
      
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