Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Sign swapping - spacelike intervals

  1. Dec 21, 2014 #1
    Hello guys!

    I´ve seen that for spacelike intervals, ie [itex] s^2 < 0 [/itex] you´re able to swap the sign of s = x-y = y-x. Why is that?

  2. jcsd
  3. Dec 21, 2014 #2
    Supposedly there exists a continous transform between x-y and y-x for spacelike intervals, but not for timelike ones. Can anyone show me that?
  4. Dec 21, 2014 #3
    Figured it out! The reason is that for spacelike intervals it is possible to choose a reference frame such that the two events x and y occur at the same time. This however is not possible for timelike ones.
  5. Dec 22, 2014 #4


    Staff: Mentor

    Take the axis which is 45° between x and y. Rotate 180° about that axis. Now you have swapped x and y, and since every rotation about that axis less than 180° is also a valid transform, the transform is continuous.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Sign swapping - spacelike intervals
  1. Signs of a multiverse? (Replies: 23)

  2. Sign of Gravity (Replies: 2)

  3. Math signs (Replies: 1)

  4. Sign conventions (Replies: 4)