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B How do you know the size/maximum area of a gravity field

  1. Mar 20, 2017 at 1:03 AM #1
    The title said it, how do you know the size or maximum area of a planet's gravity field can cover. The reason i asked this question because from the gravity equation the r is the radius from Mplanet and Mobject. So, that doesn't explain how big is the gravity field. Is it when the gravity force become 0?
     
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  3. Mar 20, 2017 at 1:20 AM #2

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    There is no maximum. The gravitational effects go forever. They may become negligible, since it decreases proportional to 1/r2, but it never completely disappears. As object A gets farther from one other object B and closer to a third object, C, the gravitational effect of C may become greater than that of B, but the effect of B is still there.
     
  4. Mar 20, 2017 at 1:25 AM #3
    Thanks for the answer, i still have one more question that i forgot to ask, why does gravitational force weakens as it get farther from a planet. I'm really confused. I also don't understand why when you get near fire it's hot and when you get away from it, you don't get any heat. thanks for answering!
     
  5. Mar 20, 2017 at 1:33 AM #4

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    For heat from a fire, the energy of a source gets spread out, so less of it hits another object of a fixed size as it gets farther away.
    For gravity, the true answer is beyond my expertise on the subject. A mass distorts space-time in a certain way that is the subject of General Relativity.
     
  6. Mar 20, 2017 at 1:38 AM #5
    Okay, that really helped me to where i should find my answer, thanks for answering :)
     
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