Using Special relativity theory, of course. Can Lorentz
transformations to "tell" something about it? "Wikipedia's"
article: http://en.wikipedia.org/wiki/One-way_speed_of_light .
The big misunderstanding about this "one-way speed of light"
thing is that there is something to be proven experimentally.
While it is just a matter of convention about Let me explain
with an example. Consider a following experimental setup: Here
is the space-time diagram for the process with the "standard"
speed of light: But now the observers have some doubts -- why do
they presuppose that the speed of light is the same in both
directions? So they agreed to change that and see what happens.
Say that right-speed is three times as fast as the left-speed:
The description has changed. But it is just a change in the
coordinates. It couldn't possibly affect any experimental
predictions by any theory that observers have. So it is just a
convention. And there is nothing to be "proven" experimentally.
Revision: use a stationary and moving d