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Speed of light in a vaccuum

  1. Apr 24, 2010 #1
    Speed of light in a "vaccuum"

    My question is: What is this "vaccuum" vacant of? Unless the vaccuum is at -273 degrees C it cannot be vacant of electromagnetic waves due to black body radiation from the material surrounding it. If this is true, then the statement that light can propagate through a vaccuum has never been proven.
  2. jcsd
  3. Apr 24, 2010 #2


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    Science Advisor

    Re: Speed of light in a "vaccuum"

    "Vacuum" simply means no physical material, not that it is free of electromagnetic waves.
  4. Apr 24, 2010 #3


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    Staff: Mentor

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