From: helbig@asclothestro.multivax.de   
      
   In article <653df735-e001-45b6-9497-fb0797b26163@googlegroups.com>,   
   Nicolaas Vroom  writes:   
      
   > The general idea is to place two identical clocks (or hourly glasses)   
   > side by side.   
   > When you move one (this always requires some force) its behaviour will   
   > change and the clock will run slower.   
      
   First, this has nothing to do with relativity.  Second, I could imagine   
   the hour glass tilted slightly in the direction of motion.  When   
   accelerated, it would then run faster.   
      
   > My first guess is that a clock based on the decay of unstable elementary   
   > particles (its counting rate) is not constant over a long period.   
      
   I'm not sure what you mean here.  Radioactive decay is an exponential   
   process, often described by the half life.  We can observe that   
   increasing for particles moving quickly.   
      
   > In most experiments (in books) one clock stays on earth and in other clock   
   > is ejected in space with a speed of 0.3 * c.   
   > The observer on earth is considered in his reference frame at rest.   
   > If that is commonly accepted, I have no problem.   
   > Maybe it is better to consider the observer always hypothetical   
   > at the centre of the earth.   
      
   The Earth is moving around the Sun, the Sun is moving around the galaxy.   
   What matters in the twin paradox is who has the strongest acceleration.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)