Re: Reference frame of photon?

["John S. Denker" <jsd@MONMOUTH.COM>]

Savinainen Antti wrote:
> ... [he] read that time does not pass at all in this frame.
> I replied that I am not sure if it is valid to speak about
> reference frame of a photon in special relativity at all.
> I promised to find a more definite answer.

You've got the physics figured out.  Perhaps rewording it
a little will allow common ground with the student:
 -- Without mentioning the word "frame" you can say that
  zero proper time elapses along the worldline of a photon.
 -- It is physically impossible to have an observer comoving
  with the photon.
 -- In general, when presented with pathological extreme
  cases, it pays to analyze non-extreme cases and _afterward_
  pass to the limit.  In this case, consider Bob who is moving
  at v=.9999 relative to Alice.  Bob's frame looks to Alice
  like a very nearly squashed rhombus.  In the limit v->1
  it becomes completely squashed, and is no longer a frame
  at all.

This posting is the position of the writer, not that of Alice or Bob.

This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.