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Kruskal and Penrose diagrams for a Minkosky spacetime

  1. Oct 28, 2009 #1

    I'm looking for diagrams (Kruskal and Penrose diagrams) representing Minkosky spacetime.
    I found two diagrams at http://nrumiano.free.fr/Estars/int_bh.html (the two first diagrams of the page). Do they represent a Minkowski spacetime ?

  2. jcsd
  3. Oct 30, 2009 #2


    Staff: Mentor

    The first diagram looks OK, but I haven't heard the term "Kruskal diagram" used to describe such a diagram of Minkowski spacetime; I've only heard "Kruskal diagram" used to describe a diagram using Kruskal coordinates for black holes (which looks somewhat similar).

    The second diagram looks similar to the one on the http://en.wikipedia.org/wiki/Penrose_diagram" [Broken]. The latter form makes more sense to me since, as I understand it, Penrose diagrams are supposed to represent a "spherical" sort of coordinate system, where the spacelike dimension is radius r. In this interpretation having a left half of the diagram would correspond to a negative radius, which doesn't make sense.
    Last edited by a moderator: May 4, 2017
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