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Thread: the sun

  1. #1 the sun 
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    hey, i just saw as show called the sun on the science channel. It said something like in the core of the sun light travels at a very slow speed and takes something like 300 thousand years to get out of the sun. They didn't say so but I'm pretty sure this is because of the gravity. Anyways, does anyone know what the speed it travels at in the core is?


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  3. #2  
    Forum Sophomore basim's Avatar
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    it might not be due to gravity alone. may be density.


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  4. #3  
    WYSIWYG Moderator marnixR's Avatar
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    + also the fact that the core of the sun is not gas but plasma

    my impression was that a lightbeam gets jostled around so much that it doesn't travel in a straight line
    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  5. #4  
    Forum Ph.D. Cat1981(England)'s Avatar
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    I have read that we can slow light down to just a few miles per hour, but i have no idea how they did it.

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    If its 500,000 kilometres from the outer edge of the sun to the centre and this takes light 300,000 years then that would be ...... 1.6 kilometres per year, 0.004 k per day, 0.00018 kilometres per hour . Of course thats its average from start to finish. Are you sure it was 300 thousand years?
    Eat Dolphin, save the Tuna!!!!
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  6. #5  
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    i thought it was 300 thousand years but Im not really sure. I also think it said a 300 thousandth of an inch per second but since those 2 numbers are pretty much the same I doubt my memory
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  7. #6  
    Universal Mind John Galt's Avatar
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    Photons generated in the nuclear fusion reactions in the core of the sun are absorbed and re-emitted many times during their journey to the surface (as marnix hinted at). This is why it takes them so long to make the trip. It has nothing to do with gravity.
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  8. #7  
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    oh, makes sense. do you know if my numbers are right?
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  9. #8  
    Universal Mind John Galt's Avatar
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    They appear to be the right order of magnitude. I obtained this quote with a simple google search [photon sun "travel time"]
    When this random walk process is applied to the interior of the sun, and an accurate model of the solar interior is used, most answers for the age of sunlight come out to be between 10,000 and 170,000 years.
    I recommend reading the entire article.
    http://sunearthday.nasa.gov/2007/loc...t_sunlight.php
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  10. #9  
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    interesting article. the answer is there is no REAL answer.
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  11. #10  
    Universal Mind John Galt's Avatar
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    Quote Originally Posted by shawngoldw
    interesting article. the answer is there is no REAL answer.
    There is a real answer - we just don't know what it is.
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