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Whats NASA saying?

  1. Jul 16, 2008 #1
    While on NASA Glen research website this morning I came across their page about warp drive. In the first few lines they say they are not sure if faster than light travel is possible. Not sure? So does that mean NASA thinks it may not be impossible to travel fater than light either then.

    I was under the impression it was absolutley impossible for humans to travel faster than light and will never be possible.
     
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  3. Jul 16, 2008 #2

    cristo

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    Could you give us a link to the page you saw, please? This will enable up to be clear on what they are saying, and to ensure that your question is answered correctly.
     
  4. Jul 16, 2008 #3
  5. Jul 16, 2008 #4
    They say it themselves : Maturity (?)
    :rofl:
    Well, it has been published in The warp drive: hyper-fast travel within general relativity (Class.Quant.Grav. 11 (1994) L73-L77)
    and you get something like star treck

    But the key is that you need large amounts of negative energy density. If you can do that, indeed you violate the energy conditions of Hawking and Penrose.
    It is still impossible to travel faster than light locally. In this speculation, you need to create a bubble around you, travelling with you, within which you are at rest (thus saving the day for the matter your spacecraft is made up of, which is bound by electromagnetism as pointed out in the text you linked). It would be kind of similar to what happens when a boat travels fast on water : it creates a wave because it drags water around itself (this analogy has strong limitations however). This example is intended to show that there is no magic : if you really were to do that, it is expected that you will loose huge amounts of energy by gravitational waves. So even accepting the idea that you can create such negative energy density regions around your spacecraft, you will still need to find a way to make them stable, and this might require too much energy anyway.

    I think the two things you should rememer :
    • speculation
    • locally, you still do not travel faster than light. This has never been challenged I think
     
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