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Weight of light and Gravity Speed

  1. Feb 8, 2004 #1
    My math teacher was talking to me about how NASA weighed light. If it doesn't have any mass, how is this possible? Also, he was saying that they are beginning to study a speed faster than the speed of light. Called Gravity Speed. Which has no lag, and is instantaneous. Do any of you know about these?
  2. jcsd
  3. Feb 8, 2004 #2

    And your math teacher told you the derivative of x is 0.
  4. Feb 8, 2004 #3


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    Here is a concept, read some of the other threads on the forum.

    Gravity is not instantaneous, it propagates at c.
  5. Feb 8, 2004 #4
    Perhaps you misunderstood him. Maybe he was talking about the gravitational aspects of light? Do you recall exactly what he meant by that? Perhaps be meant the same thing Alan Guth did when he wrote the following. From his class notes on The Early Universe
    The full page can be read at
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