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Alcubierre metric and gravitational waves

  1. Dec 9, 2012 #1
    This may be a stupid question, but why can't the expansion/contraction of spacetime from a gravitational wave be used to create the areas of expansion/contraction required in the Alcubierre metric, instead of using regions of positive/negative energy density? I saw on the forums about the Alcubierre drive maybe producing gravitational waves as a consequence of it's operation, but not necessarily the other way around. Or has this already been addressed?
     
  2. jcsd
  3. Dec 9, 2012 #2

    bcrowell

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    When you plug the Alcubierre metric into the Einstein field equations, you get a stress-energy tensor that violates various energy conditions (i.e., roughly speaking, negative mass-energy density is required).

    If you want to propose some other metric with gravitational waves in it, then that will be some other metric, not the Alcubierre metric.
     
  4. Dec 15, 2012 #3
    Thanks for posting - my question was, if gravity waves propagate at the speed of light, how does the expansion-contraction of the Alcubierre metric travel faster? It seems they are not consistent with each other.
     
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