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Simultaneity of events in 2 dimensions

  1. Aug 9, 2009 #1
    Hi all,

    I am not a physicist. Some engineer friends of mine and I have a question about special relativity in two dimensions. To set it up, there are 2 lights floating in space parallel to the x axis and a space ship is traveling at .8c flying parallel to the y axis towards the midpoint of the line connecting the lights. Then at some time, t, an observer, o1, between the lights at the midpoint flashes both of them simultaneously.

    I drew a quick diagram which is attached.

    1. The observer o1 will see both flash simultaneously

    2. At a different time t', the crew of the space ship will also see both flash simultaneously because of the symmetry of the problem.

    Is our understanding correct?

    Attached Files:

    • sr.png
      File size:
      1.7 KB
  2. jcsd
  3. Aug 9, 2009 #2


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    Welcome to PF!

    Hi techdirect! Welcome to PF! :smile:
    Completely! :biggrin:

    (and, more generally, even if the spaceship was not in line with o, but was still moving parallel to the y-axis, even though it would not see the flashes at the same time, it would calculate that they happened at the same time)
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