SRians PD and Randy said:
You can determine the velocity (or momentum) and position of a single photon
with a photon calorimeter. They claimed that this supports the SR assertion
that the leading edge of a light ray (the first photon) is known at all time
during its straight line flight from the source to the target.

SRian Tom Roberts said:
"A photon is a quantum object, and does not have a definite velocity or
speed. Indeed, from the form of the equations of QED it is clear that in
configuration space one must ascribe to a photon all possible speeds
(yes, -infinity to +infinity), and all possible locations (yes, all
space for emission, and all space for absorption). This is one reason
why momentum space is usually used for computations...."

So folks which of the SRians to believe???? I am certain that PD will come
up with new explanation for this contradiction among the SR brothers.

Ken Seto