Errata in Principle of Relativity diagram 
and associated text (editions 1 through 5)

Corrected diagram and associated text:

The distance from mirror QA to QB is 0.8 light second 
(contracted from 1 light second due to P's absolute speed of 0.6).

P2 is where P is at the moment his light beam reflects at QB2.  
Remember -- this is the God's eye view, where simultaneity (a moment) 
is not something that is a perception of the parties involved.  
Observations made by an omnipresent God are not dependent on the 
speed of light.  And that omnipresent being need be nothing more 
than the reader viewing this static diagram.


As part of the preparation for writing my journal article, I decided 
to confirm for myself, by way of diagramming, my assumption that 
there was a necessarily unconscious skewed aiming of a photon as 
discussed on page 22 in the second and third edition (and not 
mentioned in the fourth and fifth edition).

But my diagram quickly confirmed that there could be no such 
unconscious skewed aiming.

Therefore, I write (conservatively) in my journal article:

"Although a moving source of light-emission cannot impart additional 
speed to a photon, it is reasonable that it would affect the vector 
components of the photon's motion, creating a vector component in 
the direction of motion of the source, while the perpendicular 
vector component is diminished.  A photon does, after all, have 
a non-zero amount of momentum, and we can therefore imagine that 
a moving source of emission can have an effect on its trajectory."