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Thread: Why planets do not go closer to Sun?

  1. #1 Why planets do not go closer to Sun? 
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    If its Gravity that attracs them why they dont try to go to max gravity area?


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  3. #2  
    Comet Dust Collector Moderator
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    Because they are in motion sideways relative to the gravity well.


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  4. #3  
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    The sun's corona, essentially its atmospher, extends nearly to the orbit of Mercury. A planet much closer to the sun than that would be slowed in its orbit by atmospheric friction and would fall in to the sun.
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  5. #4  
    Comet Dust Collector Moderator
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    Technically, the sun's atmosphere extends out past Pluto. It's called the heliosphere (even though it's not a sphere)
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  6. #5  
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    what about moons than?
    thr seem to be no extended atmosphere from planets
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  7. #6  
    Quagma SpeedFreek's Avatar
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    Which is why moons don't move towards their planets - they are moving sideways relative to the gravitational "pull", and there is no atmosphere to slow them down.
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  8. #7  
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    im stil not satisfied, why will they not move towards stronger gravity pulling area
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  9. #8  
    Brassica oleracea Strange's Avatar
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    You can think of the moon (for example) as falling towards the earth but the curve of the earth falls away at the same rate.

    Or (ignoring air resistance for the moment):
    If you throw a ball it will curve down towards the ground and land after a few metres.
    If you fire a bullet it will fall at the same rate but its forward velocity will carry it further.
    If you fire an object parallel to the earth's surface fast enough then its velocity will carry it far enough that as it falls, the surface of the earth falls away beneath it. Hey presto: it is in orbit.
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  10. #9  
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    lol nice, i got that
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  11. #10  
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    If its Gravity that attracs them why they dont try to go to max gravity area?
    Some kind of centrifugal force which outweights gravity,maybe?
    Antislavery
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  12. #11  
    Brassica oleracea Strange's Avatar
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    Quote Originally Posted by Stanley514 View Post
    Some kind of centrifugal force which outweights gravity,maybe?
    You can think of that way as well (although the pedants will tell you, "there is no such thing as centrifugal force").
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  13. #12  
    Forum Ph.D. stander-j's Avatar
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    Quote Originally Posted by Strange View Post
    You can think of the moon (for example) as falling towards the earth but the curve of the earth falls away at the same rate.

    Or (ignoring air resistance for the moment):
    If you throw a ball it will curve down towards the ground and land after a few metres.
    If you fire a bullet it will fall at the same rate but its forward velocity will carry it further.
    If you fire an object parallel to the earth's surface fast enough then its velocity will carry it far enough that as it falls, the surface of the earth falls away beneath it. Hey presto: it is in orbit.
    Does that mean the Earth, or Mercury will never reach the sun (provided the sun sustains it's current state long enough for that possibility)? I always thought of it along the lines of those old penny donation funnels.
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  14. #13  
    Comet Dust Collector Moderator
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    That is correct. Objects in stable orbits will never reach the sun (at least not during the sun's lifetime, since there is no such thing as an eternally stable orbit in a system with more than two objects)
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    please give full description of helioshphere .What is this and how sun maintains this.
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  16. #15  
    Brassica oleracea Strange's Avatar
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    It is sort of the "atmosphere" of the sun (bad analogy).

    The heliosphere is a bubble in space "blown" into the interstellar medium (the hydrogen and helium gas that permeates the galaxy) by the solar wind. Although electrically neutral atoms from interstellar volume can penetrate this bubble, virtually all of the material in the heliosphere emanates from the Sun itself.
    From: Heliosphere - Wikipedia, the free encyclopedia
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  17. #16 Hi 
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    Hi Strange ,
    You are the most effective member of this forum due to which i was able to know very new things and about new and unknown topics .Thanks again .
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