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A comment on Do we really travel through time with the speed of light?. Parent comment

Re:Do we really travel through time with the speed of light? by dnautics on Monday August 31, 2020 @10:56AM (#24332080)
> That is, if I fire Alice light beam at you from a moving train, while Bob fires a beam at you from a platform, both beams will reach you at the same time.

That's wrong. Simultaneity is ill-defined in relativity.

The correct example is, "if Alice fires a light beam at you from a moving train and Bob fires a light beam from you from the platform, you will measure the Alice photons as going equally fast as the Bob photons.

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Re:Do we really travel through time with the speed of light? by tsimionescu on Monday August 31, 2020 @11:13AM (#24332277)
Absolute simultaneity is ill-defined, but simultaneity in my frame of reference does exist.

However, you're right, your formulation is more precise, and actually possible to measure.

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