Where is most "gravity", inside or out?

Discussion in 'Pseudoscience' started by nebel, Feb 29, 2016.

  1. nebel

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    or, talking of line #4, over a short distance with increasing thickness of the sphere.
    What would be educational to know, or see is, how that line would change if the 3 definition of gravity would be strictly allied. For example
    does potential gravity or gravity potential still have the flat zero value in the interior ? and at infinity?
    are there gravitational fields emanating from the walls of the shell inwardly?, filling the void un-cancelled as Newtonian or Gauss type calculations show? and how would that alter the graph?
    we could have 3 different shaped curves for the 3 aspects of gravity. -or not-,(I do not know) but would any of it give more gravity on the inside than the outside?
     
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  3. DaveC426913 Valued Senior Member

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    It's an infinite gradient. That's physically impossible.

    It's about how gravity behaves inside and outside a mass.
    Your diagram describes a nonsensical, impossible scenario.

    OK, you know perfectly well you're spouting nonsense.

    You're not even pretending anymore to understand gravity. This thread is nothing more than an overt exercise in spinning fanciful ideas off the top of your head as you think of them.

    You discuss in bad faith and waste our time. Back on Ignore for you.
     
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  5. nebel

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    I suggested to you to get the distinction between the 3 aspects of gravity, to give line #4 a slant to remove the "impossible" or theoretical scenario of a zero thickness sphere to one with some volume for the mass. That would give slant to line at #4. then
    how would that the dark line#2 change if you want to show
    Gravitational potential?
    Gravitational force?
    Gravitational field strength?
    Others have thought, uttered those words too. describe to us please how these 3 lines would differ from the dark line #2 above.
     
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  7. exchemist Valued Senior Member

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    Welcome back to the club

    Please Register or Log in to view the hidden image!

    .
     
  8. nebel

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    well, no, I am asking simple fundamental questions that may be too simple for you to merit an answer. The above suggestion to have 3 graphs instead only 1 from nebel. is to comply from your demand to specify. This is no nonsense. In the ring picture above, there is a real zero gravity zone in the empty center. (except for those 90 degrees orbiting stars). The sero gravity inside shells is not nonsense, but accepted theory. so
    rather shunting nebel aside, or using the N word, "nonsense" in the hope that the problem will fix itself, why not go to the graphs?
    rather than clubbing nebel, try the 3-graphic answer.
     
  9. DaveC426913 Valued Senior Member

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    Don't.

    I won't speak for others, but I am not here to refute or corroborate your fanciful ideas. They have zero merit, you're making it up as you go, and you have zero interest in how gravity actually works.

    It's a pity, really, because, if you wanted to actually talk about gravity, it could have been pretty interesting.

    Signing off.
    Again.
     
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  10. exchemist Valued Senior Member

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    Indeed. As usual it was the incidental discussion of science that this provoked that was the interesting part. I think we've exhausted that now, though.
     
  11. nebel

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    no, it is not the time, imho to beat a victorious retreat. there are still some real science question left hanging in this pseudo science project: for example:
    What do those 3 aspects of gravity identified by Dave NE & others
    Gravitational potential?
    Gravitational force?
    Gravitational field strength?
    or net and gross gravity
    look like as graphs when describing situations with a central cavity? or when in a shrinking globe, more surface gravity appears where there was previously weak interior gravity. ?
    Do all aspects of gravity come to zero, or minimum at the center? or only one?
     
    Last edited: Jan 18, 2019
  12. nebel

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    2,469
    An answer might be derived from this exchange, below, where we could picture gravity force lines opposing each other , but existing because matter is held apart by stronger forces. but there, because after being opposed, competing and seemingly Non-existing similar to interfering waves, re-emerge at the surface in full strength. Time dilation exists because gravitational force exists, albeit competing and opposed. The below quote is from another thread, but deemed crucially important, remove it if offensive.

    DaveC426913 said:
    "Take an object of typical density, and say, 4000 miles in radius.
    Pick a point inside it, say, 3000 miles from the centre.
    The gross gravitational force is the sum of the gravitational force of every single atom everywhere in the body.
    It just happens that some of those vectors (magnitude AND direction) point in opposite directions (which result in a lower net gravity)
    .

    The gross effect of every atom is accounted for. They're just competing - resulting in a smaller net force, not a smaller gross force.]"
    thank you.

    Talking of the gravitational force, when two or more of those atoms are compared, seen together, is the gravitational force between them cancelled or are they still attracted to each other while being held apart by the structural strength of the other forces? is the net force you identify the free, unopposed vectors outside the surface, even the ones that come from the atoms near the opposite surface? Only inside is any gravity opposed temporarily, because the same gravitational force component emerges from the surface with its appropriate strength, as if it never had been "opposed", "competing" in the interior. Thus,
    The full, gross gravity force exists only in the outside, the "lower net gravity)" on the inside.
    for consideration.
    Inside gravity force is opposed by other forces and the structure.so:
    Where is more gravity, inside or out? outside, because there is where the gravitational force is un- opposed, not competing , full, gross.
     
    Last edited: Jan 18, 2019
  13. James R Just this guy, you know? Staff Member

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    39,383
    Part of the difficulty in discussing physics with you is that you use the terms in ways that make no sense. Forces don't have structural strength. They are forces, not structures.

    Also, didn't I explain this to you earlier? Gravitational fields add as vectors at any point in space. The force on any mass at that point is determined by the magnitude and direction of the net gravitational field at that point. It's not a particularly difficult concept to grasp, as long as you understand what a vector is and how vectors add together. Maybe a lack of understanding in this area is what is causing you difficulties.

    The net force is the vector sum of the individual forces acting. The world isn't divided into "opposed" vectors and "unopposed" vectors. Vectors add up; that is all.

    1. Nowhere is gravity "opposed".
    2. You didn't explain what you meant by the "same" force component. Same as what?
    3. Forces don't "emerge" from anything.
    4. Forces are not "opposed". They just add up, as vectors.
    5. Forces aren't a competition. They are vectors.

    No. The full force of gravity exists everywhere. In some places, gravitational fields from individual mass elements tend to supplement one another; in other places, they tend to cancel. It's just vector addition.

    The "structure" is conceptually separate from the forces. If you like, it is the "structure" that results in the forces.

    It's meaningless to talk about "more gravity", unless you define what you mean by "more" in this context. There are now 450 posts in this thread and you have yet to do this in any coherent way. Why is that?
     
  14. Iskcon Registered Member

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    It is already stated by me, that when we speak of gravity then it means by default the gravitational acceleration (a measure of gravitational field strength) in Newtonian Mechanics. In GR the default is curvature of the spacetime, like when we say weak gravity, it means curvature of the spacetime is very small, around Black Holes the gravity is very strong, means curvature of the spacetime is significant.

    Gravitational force in Newtonian is simply mg (a vector quantity), so more or less gravitational force and gravitational acceleration or gravitational field strength is same. Like when we say moon surface has less gravity than Earth surface (recall jumping pics of Neil Armstrong), it means 'g (moon) is less as compared to g(Earth) on the respective surfaces. Moreover, for a spherical object, if you go away the g reduces (reduction of g with respect to height from the surface) and if you go below the surface then also g reduces (g value at a given depth).

    Next qty is Gravitational Potential, this is reference based, standard convention is zero at infinity, it represents gravitational potential energy per unit mass. Majority of Newtonian Physics numerical problems are solved by referring the potential energy zero at the surface, as you go up the potential energy increase (work against g force) and as you go down the potential energy decreases (attractive force). When we say gravity is strong, it never means gravitational potential is strong, unless it is specifically stated.
     
    Last edited: Jan 19, 2019
  15. Iskcon Registered Member

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    19
    This is a conceptual issue.
    The confusion will go away if you spend some time with Gauss Law for Gravitation or more fundamental Poisson's equation.

    This is incorrect, and meaningless unless you quantify what point of inside or outside.

    A high school level physics link is given below, you would see that gravitational acceleration (and thus the gravity) decreases faster as we go up (outside) as compare to when we go inside.

    https://gradestack.com/CBSE-Class-1...cceleration-due-to/17543-3563-24279-study-wtw[/quote]
     
  16. nebel

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    2,469
    Thank you, that is impossible for me, who's formal education basically stopped in 1943 with Stalingrad. autodidact since then.

    " where is more gravity "
    I meant Any and all points, the area through which gravity acts. Comparing the strength of the pull to equal distances in and out from the surface and then factoring in the different areas of .5 R and 1.5 R for example, to establish more or less. "in total".
    yes, like in the graph of origin in post#2:

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    The slope is steeper at some points on the outside, but for example, gs is 1/4 at that radius, almost at the end, the center, , but equal to that at 2R, and still an infinity to go toward the outside, in ever increasing volume. so,
    By default , in my primitive ways, which might be shared by some viewers, I meant
    a) Gravity as felt in quality, strength and
    b) qualitatively in acting everywhere within a given volume. c) the two axb combined. thank you!
     
  17. nebel

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    2,469
    My impression is that the gravity vectors at the surface are the ones that have supplemented each other. the cancelled ones never made it to the surface from the inside.

    sorry, but it seems to be a language problem, which does not detract from the merit of the subject matter discussed. I just have to express myself in really down to earth terms, and some viewers might only be able to follow in these terms too. Interesting facets of gravity have been highlighted in the process though, not a waste of time imho.
     
  18. James R Just this guy, you know? Staff Member

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    What's a "gravity vector"?
    How can a vector move to the surface of something? How can a vector move at all?
     
  19. nebel

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    2,469
    indeed? looking at the different vectors on Wikipedia, did nothing for me to get a clear idea without serious help.
    Only when freed from the gravity effects of other bodies of the interior, is the full force present, and that is outside the surface.
    sorry, vectors are too vexing.
     
    Last edited: Jan 20, 2019
  20. nebel

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    2,469
    To look at this statement, how does it apply to the interior of an entity?
    let us take a very small body, with no interior, but mass, all the gravity would be on the outside. Now,
    have another such body approach. Then you have an "interior" the line between these two bodies.
    Outside that line, beyond the two bodies, the vectors, gravity adds up. but
    between the bodies, gravity pulls in opposite directions and there is a zero gravity point in the middle, diminished gravity between the 2 "centres" of mass. In a way,
    Gravity in that, or any interior, results in a situation like with interfering waves, (and change in gravity is supposed to move at "c" along that line) It is clearly there, because, if it travels, it emerges at the opposite end, outside of the other body, but is cancelled, interfered with in the interior, the line, location of the opposing vectors. so, can we say:
    There is no inside gravity, all gravity is outside, because it is the combination of gravity outside many very small masses. ? so, along that connecting line,
    How do they cancel? wavelike passing through each other? by-passing gravitons?
    A big gravitational field stretching to infinity with minor local cancellations embedded in it?
     
    Last edited: Feb 20, 2019
  21. exchemist Valued Senior Member

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  22. James R Just this guy, you know? Staff Member

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    Vector addition, like I said. (Newtonian) Gravity is a vector field.

    You mean a point mass? Obviously, since a point mass has no size, there's no "inside" that we need to worry about there.

    Are we talking about 2 point masses separated by some distance, now?

    You mean if you moved a third, pointlike test mass along the line between the two point sources, then it would have zero net force on it when it was half way between the two? That is correct.

    Simple vector addition. This has nothing to do with waves.

    The "speed" of gravity is a separate issue and not relevant to the discussion here, as far as I can tell.

    Wait a minute. If what travels? We're talking about static gravitational fields here, aren't we? It's just vector addition of field components from two source masses.

    Vector addition. Do you understand how to add vectors?
     
  23. Write4U Valued Senior Member

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    Question; are gravitational fields static? I read this and it made me wonder.
    https://en.wikipedia.org/wiki/Vector_area
     

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