The TimeLord wrote:
Proper time is defined as
the time that passes on the object when it is free of gravitational
fields and not moving.

Not true. the proper time of an object is the time elapsed on an ideal
clock that remains collocated with and comoving with the object. Whether
or not someone thinks it is "moving" [#], and whether or not there is
gravitation present, does not affect this definition (though they can
affect the relationship between the object's proper time and other
clocks). Indeed, it is essential to GR that the proper time of an object
be related to that object only, completely independent of its environment.

[#] Proper time is that of the object itself. The object,
of course, does not consider it (itself) to be moving.


Tom Roberts