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On plane of simultaneity

  1. Jan 31, 2007 #1
    Please explain following on simulataneity..
    Two far removed relatively at rest observers are on the plane of simultaneity.But if some event occurs in the close vicinity of observer1, he will see it immediately whereas it will take years for oberserver2 to see that event; and vice versa. So the events are not simultaneous for them (unless they happen at the middle of the line joining both obeservers ). are they still on the plane of simultaneity (Given that their clocks are synchronised)?

    OR being on the plane of simultaneity just means that time of the event (by the clock located at the location where event occurres) and time that both relatively at rest observers' clocks show is same, but they may not see the event ??

    And also please tell me where I can read more on this plane of simultaneity and effect of distance on time dilation??

    Thanks a lot
  2. jcsd
  3. Jan 31, 2007 #2


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    Simultaneity has nothing to do with when you see events, it has to do with when you calculate they occurred in your rest frame, given the assumption that light travels at c in your frame. For example, if in 2007 I look through my telescope and see an event taking place 7-light years away according to my rest frame's definition of distance, and then in 2008 I see an event taking place 8-light years away, once I take into account the time the light from each event took to reach me, I'll conclude both events happened "simultaneously" in my frame in 2000.
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