Where is most "gravity", inside or out?

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

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

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    nebel:

    You're use of language is strange here.

    What exactly do you mean by "there is more gravity..."? Obviously this can't be simply that the magnitude of the gravitational acceleration is larger, since the gravitational acceleration for a planet of uniform density is greatest at the surface, and lower both in the interior and the exterior.

    Please explain what, exactly, you mean by "there is more gravity outside than in". In what way is there "more"? More of what? Explain.

    That's not true. The external gravity of a planet depends on the entire mass of the planet, not just mass on the surface. Or did you mean to say something different?
     
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  3. origin Heading towards oblivion Valued Senior Member

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    The statement that I quoted.
    Nebels quote:
    The tiniest entities, say of Plank size, when coming near each other, drawn by their mutual surface gravity, when joined, have zero gravity between them, because the gravity has migrated to the mutual outside.

    The statement that there is zero gravity between them is false. The statement that gravity has 'migrated' to the outside is false.

    His wrong thinking has been pointed out to him several times by different posters, but he continues to make these statements. All I am saying is that if he wants to continue with his flights of fantasy he should do it in the proper section.
     
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  5. Write4U Valued Senior Member

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    Allow me an example of what I believe he posed. It is said that the earth is made up of two bodies, Earth and Thea.

    At one time each had its own (surface) gravity, until Thea slammed into the earth and partially merged with the Earth. The part that was sheared off became the moon.

    But the new Earth's gravity was now a composite of Earth and Thea, inasmuch that there was no longer any division but a single body exhibiting the combined gravity of each object.. Not a good example?
     
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  7. origin Heading towards oblivion Valued Senior Member

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    That is a simple example of how gravity is related to the mass. The more mass the more gravity. If Nebel had said that there would be no issue.

    This is an extension of the strange idea that if you compress a mass then there is MORE gravity. That is just nutz. Exchemist did an excellent job of describing what is actually going on and why the ACCELERATION at the surface increases as the mass contracts and becomes more dense. Nebel said paraphrasing, "no, there is more gravity near the surface of the compressed mass and where does this gravity come from?". So exchemist gave up trying to help him to which nebel said
    "hopefully not a tacit admission that you have come to a dead end in your arguments (not appealing to authority). Because the question that remains to be discussed : how can you have more gravity, but not more mass"

    I am not interested in continuing a discussion what nebel might or might not mean. It is in the hands of James and the moderators, they will do what they deem fit.
     
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  8. nebel

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    James, since this is the amateur section I take the liberty to use layperson's phrasing with a dash of hyperbole sometimes.! when
    I said "living proof " I appealed to the fact, that without the compression created by increasing gravity in a shrinking globe we would not have stars, supernovae, elements, planets, us.

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    The situation referred to was not about a planet, but a shrinking globe, planet or star if you will. so: In the process of compression, in the volume defined by the green lines, -the space that is no longer part of the globe,- stronger gravity on the outside (red) has replaced the weaker , (sloping blue line) formerly inner gravity. and
    Since the inner and outer gravity strength near the surface is roughly equal, but the space outside is vastly greater, there is much more gravity in total outside, stretching even to infinity, whereas the already smaller inner gradient dives to zero quickly. So , in any contracting entity,
    A weaker, and smaller gravity field in the interior will be replaced by a stronger and larger gravity field on the outside surface, in addition to the residue gravity always remaining to infinity.(blue curve).
     
    Last edited: Jan 4, 2019
  9. nebel

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    You are right, the total mass at all times determines the outside and inside gravity strength, gradients. but
    I was not referring to mass near the surface, but the force of gravity there. Gravity that clearly is a feature, kind of emanating or projecting outwardly , never inwardly from a mass; -- because
    To understand the situation you have to treat the interior of a globe as a stacked series of shells, and irregular masses as more or less close approximations.
    sorry for the confusion, but I think my statements were correct, even if they were expressed unconventionally, which, bsw might be a great teaching tool.
     
    Last edited: Jan 4, 2019
  10. nebel

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    Please Register or Log in to view the hidden image!

    I am using this image from BBC science to illustrate my Inside / Outside & developing gravity understanding. In the image,
    The object's center of gravity, and axis of rotation, lies about on a horizontal line level with the (33 km) writing. That central point is surrounded by equal masses in all directions, pulling with equal force, cancelling the forces; therefore:
    there is null, zero gravity there now. However before this entity came together into that shape, there were strong surface gravity fields projecting out from both globes. Those fields, at contact, were eliminated and a new total gravitational field now surrounds Thule Ultima[tely].
    When two soap bubbles merge in similar manner, you can actually watch the surface tension migrate to the common outside
    Gravity too is an outside, strongly surface phenomenon. so, given this,
    I suggest that your "false" comments were given without serious thoughts as to the science behind all this, and your constant clamouring to have the stuff moved into the pits is not worthy of the good work you do otherwise.
    at least it deserves to be in 'alternate'. imho. thank you.
     
    Last edited: Jan 4, 2019
  11. origin Heading towards oblivion Valued Senior Member

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    Maybe this is the crux of the problem. Your terribly sloppy use of words makes it nearly impossible to understand what you are saying. Write4u has one interpretation and apparently I have a different one. I believe I understand what you are trying to say - which mean you have some misconceptions, but it may be that you are just not communication well.
    It is vital that you use the correct terms to describe a complicated phenomena. You say you like to use 'laypersons terms' with some 'hyperbole'. That is not acceptable if you really want to discuss science - that is what is found in the fringe section.

    Lets look at the line I quoted above:
    nebel said:
    That central point is surrounded by equal masses in all directions, pulling with equal force, cancelling the forces;
    That is correct!

    nebel said:
    therefore: there is null, zero gravity there now
    That is incorrect!

    The 'gravity' is highest in the center of the earth. Gravitational time dilation is greatest in the center because the gravitational potential is highest in the center of the earth even though the gravitational force is essentially zero.

    If you were crewing on a sailboat and you said tighten the rope no one would know if you were referring to the Halyard, main sheet, jib sheet, cunningham, downhaul, etc.

    My false comment was based on the science.
    This stuff in not science and should be in the fringe section. It is not a slam - if it ain't accepted science don't put it in the science section!
     
  12. NotEinstein Valued Senior Member

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    Thing is, nebel doesn't care. I pointed this exact thing out to him, in exactly the same context a couple of days ago:
    (I didn't add "potential", because it hadn't been mentioned and I didn't want to add more fuel to the burning trainwreck.)

    nebel just doesn't care.
     
  13. origin Heading towards oblivion Valued Senior Member

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    Agreed. He likes pseudoscience and numerology because it is way easier than actual science. It is just sad to have it stinking up the science section.
     
  14. NotEinstein Valued Senior Member

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    James R is on the case now, so with a little bit of luck, all things will soon be put in their proper place.
     
  15. nebel

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    do you have a link to this? How can you have the relativistic effects associated with the force of gravity when no force of gravity would be measurable in the center of mass?
    The potential of gravity would be only felt, if half of the mass would be removed.
    As an amateur (from the french "aimer" like or love) which is in the criteria for this section,--. When I use the word gravity, you might assume that it is meant in the most general way. Gravity as it can be measured in situ, zero at the center and remaining zero everywhere even if you hollowed out the interior.
    May be I am not an amateur but a dilettante.
    For example: When I say "more "gravity I mean stronger acceleration measured in one place, compared to another, -- or the same strength measured present in a much larger space, (the [new] exterior). compared to a smaller one, (the interior)
    "more" in quality, and /or more in quantity.
     
    Last edited: Jan 4, 2019
  16. nebel

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    2,469
    Yes, it has to be, as I myself often asked. Posting is always tentative, subject to correction.
    Not that decisions will be perfect. Example: I think that classing of the "cancelling of orbital and rotational velocity" has enough solid stuff in it to be seen as an alternate theory rather than totally, or predominantly 'pseudo". imho
    Remember, a discussion can meander into strange fields (like copyright issues), but that does not render the big issues raised in the OP thread as "Fringe", "pseudo" or worthy of the pit.
     
    Last edited: Jan 4, 2019
  17. origin Heading towards oblivion Valued Senior Member

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    Let's slowly walk through this, shall we?
    Ok the big points were time dilation and gravitational potential. Go to Google and put those 4 words in the search bar and that will give you the links you are looking for.
    That would mean that relativistic effects are not associated with the force of gravity.
    What is 'the potential of gravity', how is this felt and what would removing half the mass do?
    That is not a criteria.
    I would assume you mean the accepted definition.
    Just use the accepted definitions.
     
  18. nebel

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    re: use of hyperbole, jesting in scientific discussion: how about
    A.E.: " funny action at a distance " The Lord does not play dice"
    Fred Hoyle: "Big bang"
    Erwin Schroedinger : das Ding "The cat".
    That is why some pure science debates, writings are boring, some participants do not emulate the style of those that really knew, deep down, what they were talking about, hiding behind formalities, instead are trying to stifle a more open style, even trying to shut down, or degrade contrary views, so:
    where were we? stronger and more pervasive gravity, inside or out?
     
    Last edited: Jan 5, 2019
  19. nebel

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    No, please give us your view, your understanding of this particular situation, question raised here by you, and in your words, better yet, with one of your appreciated origin[al] graphs. :
    At the center of an uniform density sphere, with equal mass in all direction, gravity field cancelled out., zero acceleration measured,
    Is there time dilation because gravity is pulling in all directions? thank you. because
    all I was saying that is: that there is zero [measurable], effective gravity in the center.
    If clocks really low down, as measured. --perhaps it is because of the high speed, closer to "c" of the particles in zero gravity, but under such high pressure?
     
    Last edited: Jan 5, 2019
  20. James R Just this guy, you know? Staff Member

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    nebel:

    I can't see the image you are referring to. Perhaps you tried to embed it in your post, but it didn't work. I can't tell what you're talking about here.

    I still can't work out what you mean when you say there is "much more gravity" somewhere. It sounds like you think gravity is like a substance that varies in density, or something like that. Gravity is a force (let's go with the Newtonian picture unless we find we need General Relativity). We can meaningfully talk about the acceleration due to gravity at any point in space, but talking about "much more gravity" seems meaningless to me, unless you simply mean the acceleration due to gravity is greater. It sounds to me like this is not what you mean, though. So, I'll ask again: what do you mean when you say there is "much more gravity" in one place, compared to another? Be precise.

    It is possible that all you are saying here is that as a spherical mass is compressed, the acceleration due to gravity at its surface increases. That is correct. Is that all you're saying?

    That's false. The gravitational field from a mass projects in all directions. Every bit of mass attracts every other bit of mass, at the fundamental level.

    Irregularly-shaped masses are seldom close approximations to spheres.

    I don't know how you know this. Assuming approximately uniform density, that looks reasonable, though.

    No, because the object is clearly not spherical. There is a distribution of mass at different distances from the centre of mass of the object. Mass close to the centre of mass produces a stronger gravitational field there than mass that is further away from the centre of mass. Overall, though, all the fields from the individual mass elements add up (as vectors) to create zero net acceleration due to gravity at the centre of mass.

    The fields of the two "pieces" of the combined object simply add as vectors everywhere to produce a net field. Nothing about the fields of the two pieces taken individually changes, regardless of whether the pieces are far apart or joined as we see in the picture. The net gravitational field of the joined object is simply the superposition of the individual fields of the two pieces.

    There's no "totally new gravitational field" at work here - just a combination of the two pre-existing fields from the masses of the two pieces.

    Surface tension is not the same as gravity. It is, as the label says, a surface or boundary phenomenon. Gravity is a bulk phenomenon.

    This is quite wrong, I'm afraid.
     
  21. nebel

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    2,469
    thank you fort hat interesting sub-question. I am thinking of a balancing scale having a zero balanced position, and the gravity of one one half of a globe on one side, the other hemisphere -generated gravity on the other. One full blown, total central gravity, but split in half and put respectively on each side of the balance, with an effect of zero. Now
    You remove one of the halves, one side of the 1/2 gravities, and-- you will have a big spill, proving there really were two half gravities balancing each other. but
    Are there really?, or is there a zero balance, an a priori cancellation ? Around the center?,
    Gravities in a balance, or cancelled outright in the first place?
     
  22. James R Just this guy, you know? Staff Member

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    Like I said, it's a simple matter of adding the effects of individual mass elements as vectors. Gravitational fields obey the principle of superposition, at least in the Newtonian picture.
     
  23. nebel

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    I can see the image in post#

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    265
    The place in question, with changing gravity is one and the same, defined by the small green bottom arrow, and bordered by the green vertical lines. That space, or volume, a shell really, - prior to the contraction phase hat gravity shown by the short segment of the blue line, of interior gravity gradient, marked : "gravity lost".
    After the contraction, the now, smaller globe has the higher surface gravity marked " g surface" , all shown in the red curve and peak.
    The space in question is the one enclosed by the green lines, and during the contraction it was vacated of its mass, and lost its small interior gravity (in blue) but gained the stronger pull shown in red. Additionally, even the interior now has an increased gravity strength, still with zero at center though.
    My statement was that contraction produces higher gravity, which was contradicted by posts to the effect that gravity stays constant because mass stayed the same.
    the image is a graph from origin in post #2 that we reworked twice to show the effects.
    PS: what I took from this exercise was, that since all entities, galaxies, stars. planets, moons were from contractions from "greater "clouds" of matter, having a certain mass and therefore gravity, more overall gravity was created during the contracting phase. More gravity within the same size cloud, without changing the contained mass. surely nothing new there.
     
    Last edited: Jan 5, 2019

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