## Illustration 2: Viewing Synchronizing Clocks

viewer x  =  m               viewer z  =  m

What we, as omnipresent observers, are recording after the synchronization of clocks is not what a viewer of the clocks would see.  What we are depicting in this animation is not what an intelligent observer or an omnipresent observer would observe.  A viewer would not see all of the clocks synchronized because of the light-travel time delay.  Instead he/she would see what depicted by a viewer.  Note that when we talk about reference frames and synchronized clocks, we do so in the sense of what an intelligent observer or an omnipresent observer would see (and therefore light travel time delay is not factored in at all).  Often students (and physicists alike) mistakenly believe that all of the strange things that are a part of special relativity are due to light-travel time delay, they are not.

Vary the x and z positions of the viewer to see the effect of light travel time on the clock readings as seen by the viewer.

1. How do the clock readings change as you vary the x position of the viewer?

2. How do the clock readings change as you vary the z position of the viewer?

3. Where does a viewer need to be located in order for the clocks to appear (approximately) synchronized?