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Re: SR examination question



Michael Edmiston wrote:
* * * * Question for Michael Moloney and Geoff Nunes

Sam and Jane are in the same reference frame, but vastly different positions
in that frame. Please tell me how they synchronized their clocks.

John D. gave the precise answer. I tell my students to imagine that all
the observers get together in a huddle at the same location and
synchronize their watches. Then they stroll in a leisurely fashion
(v<<<c) to their assigned location to await "events." Not as precise,
but easy for the students to picture. They never seem to wonder how the
observers maintain the correct separation. Perhaps they imagine, as I
sometimes do, that the universe is full of Reaganesque tape marks
telling the observers where to stand....

John said it, but it is worth repeating: the Lorentz transformations do
not include propagation delays. If you know the coordinates of an
explosion in frame A, the transformations give the coordinates in frame
B. If Jane in frame B happens not to have the same spatial coordinate
as the event , then you have a second event: "Jane learns about the
explosion," which will have its own coordinates.

-GN