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Does Speed Of Light Scale With Size?

  1. Jan 20, 2012 #1
    My teachers in school use to say. "the dumbest question is the one not asked", but I might just break that rule with this one. :smile: Here goes....

    I've been reading a lot of articles today on light travel, the Higgs field, and other fascinating stuff. Lastly, I was just reading an article about our radio signals and what has happened to them as they left mother earth. The article had an inset showing our galaxy. I then imaged, what if I was a being large enough to hold our galaxy in my hands. Just go with me here ... I know, I know ... there are all sorts of practical impossibilities here. :wink: Anyway, I could in a fraction of a large-being second move my finger from where our solar system is to the opposite side of the galaxy. This same distance would take use, of course, billions of light years to travel. Would various theories on light, you know E=mc2 stuff, scale with gargantuan comic size differences?
  2. jcsd
  3. Jan 20, 2012 #2


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    Short answer - no!
  4. Jan 20, 2012 #3


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    I agree w/ your teachers and I don't think you have asked a dumb question, just one that demonstrates a total lack of knowledge of physics. That's not a bad thing unless you've been STUDYING physics for a while, and I'd guess that you have not (at least, not cosmology and relativity)
  5. Jan 20, 2012 #4


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    How do you know that?
  6. Jan 20, 2012 #5


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    geelsu - What makes a good investigator is someone who can ponder the "what if" scenario.

    Yours is: if I was the size of a galatic giant would I still be subject to physics as we know it on earth?
    And that is your answer - subject to the same physics that we know on earth.

    You could of course invent a whole new set of physical laws so your giant could function, ( so he could wiggle his toes just like you do ) and then ask how would those new laws affect us littler people on earth, would we be able to see the effects, and would this new set of physical laws be compatable with what we know. As an example you have already mentioned the large-scale being second versus our littler people second ( his second being hundreds of thousands of years, and not billions by the way for light to cross the galaxy ).

    Besides size, you have scaled time. Next would be force, energy, chemistry, thermodynamics, relativity, for as I have said, your giant to function. Could you make it work?
    Possibly. After many years of labourous calculations and scaling of physical laws that we know. You see that omce you scale one aspect, than you should have to consider how all others are affected if at all.

    But sticking to our "human" physics, the answer as mathman has said is no.
  7. Jan 21, 2012 #6
    It would take millions of years for your giant to move his finger from one side of the galaxy to the other. However, his perception of time would be related to the time it takes signals to cross his brain which would presumably be hundreds of thousands or light years across. So the time to move his finger and the time for him to perceive it to move would be in similar proportion to you. In other words, his sense of how time relates to distance would be similar to yours even though you perceive about 1022 times more of both.
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