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Light speed as the processing speed of the universe

  1. Jan 2, 2008 #1
    I have seen speculation that if the universe is like a computer and/or runs like cellular automata, then the speed of light can be seen as the processing speed of the universe. You can't go faster because the universe can't calculate what will happen any faster than that. I think it may have been Stephen Wolfram who brought this up. What do you think of this idea?

    Maybe it slows down in mediums like water because there is more calculation to be done.
  2. jcsd
  3. Jan 2, 2008 #2
    It does not slow down in water. Photons are absorbed and reabsorbed at the same rate, the difference is that water and other materials are different from a vacuum, so when they absorb and give off the same quanta of energy, they are again doing it in some direction that will cause this process to be repeated, so it just seems like overall it's slower, but it's really not.

    - Bryan
  4. Jan 2, 2008 #3


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    Yes, but the continuous absorption/reabsorption would be the "calculations".
  5. Jan 2, 2008 #4


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    I guess opaque objects would be a "stop" command?
  6. Jan 2, 2008 #5
    You're guess is probably better than mine. Maybe processing speed is not why light slows down. Maybe the universe stops calculating inside opaque objects, or does it very slowly. Maybe it does something totally different inside them. Who knows?
    Last edited: Jan 2, 2008
  7. Jan 3, 2008 #6
    only the phase velocity changes in water. the group velocity is still c.
  8. Jan 3, 2008 #7


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    No, a pause and a JMP ;)
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