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Thread: doubt on parallel rays of the sun on earth

  1. #1 doubt on parallel rays of the sun on earth 
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    all right the rays of the sun are parallel

    imagine the clouds just let two rays of sun 10 km apart

    according perspective of parallel lines you could see:

    *
    ^
    or
    *
    II

    or

    *
    V


    why the last two cases never appear?






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  3. #2  
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    why the sky is never like this:



    and always like this:

    [img]

    [/img]


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  4. #3  
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    Do you mean parallel as in never crossing paths or in some other sense?
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  5. #4  
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    i mean the suns supposed to be so far away that for the effect sun rays on earth should be parallel

    this is an analisis of the perspective of two parallel rays
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  6. #5  
    Administrator KALSTER's Avatar
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    Quote Originally Posted by luxtpm
    i mean the suns supposed to be so far away that for the effect sun rays on earth should be parallel

    this is an analisis of the perspective of two parallel rays
    Imagine trying to look at the sun through each of these holes in the clouds. Because the sun us a small disc in the sky, you will only be able to see it if you look at it at those angles.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
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  7. #6  
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    my point is that a book or million people say the sun is very far away doesnt make it from my point of view an scientific evidence

    after all millions of smokers cant be wrong

    myself for example i take that the earth is rounded cause i measure its radius myself so i can believe that

    im not talking about seeing the sun but seeing its rays in the mist from holes in the clouds

    the painting i made depicts the sun behind the observer(not posible to see) and there being holes in the clouds right above the observer

    then if the sun trully was so far away what i painted is what should be seen but just check how unnatural it appears

    so allow me to doubt in an scientific manner that the sun is so far away as they tell us and allow me to ponder the idea of an sky dome
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  8. #7  
    Administrator KALSTER's Avatar
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    Quote Originally Posted by luxtpm
    my point is that a book or million people say the sun is very far away doesnt make it from my point of view an scientific evidence

    after all millions of smokers cant be wrong

    myself for example i take that the earth is rounded cause i measure its radius myself so i can believe that

    im not talking about seeing the sun but seeing its rays in the mist from holes in the clouds

    the painting i made depicts the sun behind the observer(not posible to see) and there being holes in the clouds right above the observer

    then if the sun trully was so far away what i painted is what should be seen but just check how unnatural it appears

    so allow me to doubt in an scientific manner that the sun is so far away as they tell us and allow me to ponder the idea of an sky dome
    Wow, you really seem to need a drawing. You think all those people are simply "saying so"? You don't think it was scientifically determined?
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
    "All people know the same truth. Our lives consist of how we chose to distort it." - Harry Block
    "It is the mark of an educated mind to be able to entertain a thought without accepting it." - Aristotle
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  9. #8  
    Moderator Moderator Janus's Avatar
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    I have seen sun beams that are at least very close to parallel. To see them this way you need to looking in a direction perpendicular to the light, and under just the right conditions.

    It would take very special conditions for you to see sum beams that converge towards the ground. For this to happen, the Sun would have to be behind you, so that the beams get further from you as they near the ground.

    However, the reason you see the sun beams at all is that they are being scattered, generally by small water droplets in a process called Mie scattering. Mie scattering is very directional and is strongest when you are looking towards the light source. When you are looking with the light source coming from behind you, it is very weak to non-existent. In such a case, you can't see the sunbeams because not enough of their light is being scattered into your eyes,
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


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  10. #9  
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    Quote Originally Posted by Janus
    I have seen sun beams that are at least very close to parallel. To see them this way you need to looking in a direction perpendicular to the light, and under just the right conditions.
    Close to parallel but not parallel. That is why you cannot focus the rays of the sun to an arbitrarily small dot using a lens. To do so would violate the second law of thermodynamics and allow you to create a temperature higher than that of the sun from the radiation of the sun without doing any work. The best that you can do is create an image of the sun on a spot with a temperature equal to that of the source. This is a nice example of the consistency of the overarching principles of physics, in this case optice meets thermodynamics.
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  11. #10  
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    all right if the sky is not a dome how would you explain this video?

    http://www.youtube.com/watch?v=0nCY-...os=Rut-HDwyBjc

    hint

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  12. #11  
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    Quote Originally Posted by luxtpm
    all right if the sky is not a dome how would you explain this video?

    http://www.youtube.com/watch?v=0nCY-...os=Rut-HDwyBjc

    hint

    I call it a pretty sunset. What do you call it ?
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  13. #12  
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    a false sky?

    look twice
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