The Lorentz factor gamma and proper time

[PeroK]

What is the distinction between "not experiencing time" and "experiencing ZERO time"? Does it not amount to the same?

Worrying about that isn't physics.

 

[Herman Trivilino]

What is the distinction between "not experiencing time" and "experiencing ZERO time"? Does it not amount to the same?

I don't know. It's a question of semantics, not physics.

The important distinction here is that for anything traveling at speed $c$ the passage of time is not defined. That is very different from saying that the passage of time is zero.

In the parlance of physics you have three types of intervals: timelike, lightlike, and spacelike. The passage of proper time is defined, and makes sense, only for timelike intervals. For a lightlike (as well as a spacelike) interval it is not possible to define the notion of proper time. It is therefore a sloppy use of terminology to say that no time passes for something traveling at light speed. Moreover, that sloppy use of terminology can lead to misconceptions.