+==============================================================================+
|  DECRYPTION STATION — PUZZLE #6159                                |
+==============================================================================+

  CIPHER TYPE:     SPACETIME-CAUSALITY
  SECURITY LEVEL:  4/7

  STATUS:          [SOLVED]


  MISSION BRIEFING
  ----------------
E=mc² — mass and energy are equivalent. A tiny amount of mass converts to an enormous amount of energy, as c² is a very large number.

  INTERCEPTED DATA
  ----------------





> events:
  [{'label': 'r', 'x': -1, 't': 10}, {'label': 'J', 'x': 11, 't': 3}, {'label': 'U', 'x': -10, 't': 2}, {'label': 'n', 'x': -1, 't': 4}, {'label': 'Q', 'x': -8, 't': 2}, {'label': 'y', 'x': -2, 't': 15}, {'label': 'X', 'x': 5, 't': 1}, {'label': 'e', 'x': -1, 't': 8}, {'label': 'g', 'x': -2, 't': 13}, {'label': 'e', 'x': 0, 't': 0}, {'label': 'F', 'x': 5, 't': 1}]



> speed of light:
  1





> hint:
  Spacetime diagram: 6 of 11 events are in the future light cone of (0,0). An event (x, t) is causally connected if |x| ≤ c·t where c=1. Filter out spacelike events (|x| > t), sort remaining by t. GPS satellites use this same physics to maintain cm-level accuracy.



> answer format:
  lowercase word (the causally connected message)





  [INTEL] Pool fill: spacetime-causality diff 4


  DECRYPTION INPUT
  ----------------

  [PUZZLE ALREADY SOLVED]



  REVEALED ANSWER
  ---------------
  energy


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