# Synchronized clocks in two moving reference frames

## Homework Statement

My professor gave us a werid question which is as follows
In the laboratory frame, two clocks are synchronized and measure two light sources at the same time situated at 3 years in time axis and 3 light years and 2 light years in x-axis

>At what velocity is the frame ##S'## moving?

>What distance will the traveler measure between the two light sources?

Now apparently the answer to the first question is ##c/\sqrt3##

My question is "Does this question even make sense?" (and yes that is the complete question).

I was told explicitly that the traveler is in ##S'## frame and the light sources are in ##S## frame. Even if I take that assumption is the provided answer plausible?

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andrewkirk
Homework Helper
Gold Member
The question makes no sense as written.

Problems that prevent the question making sense are:

* what does 'measure two light sources at the same time' mean?
* what is the frame ##S'##?
* what does it mean to say 'the light sources are in ##S## frame'? We can meaningfully say that an object is stationary in a given frame, or that the coordinates of a spacetime event are such and such in a given frame, but it means nothing to say that a spacetime event or worldline is in a given frame.