Where is most "gravity", inside or out?

[nebel]

So the maximum work needed to remove the test mass to infinity occurs when the test mass is at the centre. That means the potential is at a minimum at the centre.

Thank you! well, yeah, that is work ahead of you, not yet done, but if you want to stay at the center, you would never have to do, and are we not talking about a static situation, that exist as we measure? Using an above illustration, to push that elephant in he center room toward the surface, you need to accelerate only the rest mass not at the outset also overcome gravity.
my continuing query is: is there not really less gravity in the inside, in strength and volume than outside the surface? after all
In your work schedule, the real heavy lifting is done near the surface, not in the center.
Ps. There is way more potential work ahead of you from the surface to infinity than from the center to the surface.
final thought: would the "potential of work ahead" affect time dilation clock reading or the actual gravity strength as it is measured? to be zero?

 

[origin]

My observation was, yes there is no gravity, therefore the clock should run faster.

My observation is that you are arrogant and ignorant and therefore doomed to learn nothing here. Too bad.

 

[exchemist]

Once again, an informative, clear and concise post, very nice.

That should answer Iskcon, now if only nebel would read and understand it. I do not hold out much hope for nebel....

Nebel I think does not understand the difference between force and energy, so there's little hope there.

 

[nebel]

Nebel I think does not understand the difference between force and energy

and to boot we are discussing neither, but, if other viewers, cases like me, - benefit, all is well.

 

[nebel]

you are arrogant and ignorant

you might have that impression, but it is off topic.(pertaining to non existing personality traits) Instead please refute this scenario:
probe detects no gravity, without gravity clocks speed up (compared to normal), so unsurprisingly, center clock runs ahead of surface clock. or?

 

[exchemist]

and to boot we are discussing neither, but, if other viewers, cases like me, - benefit, all is well.

If you understood the difference, this "discussion" would not be necessary.

 

[origin]

Instead please refute this scenario:
probe detects no gravity, without gravity clocks speed up (compared to normal), so unsurprisingly, center clock runs ahead of surface clock. or?

Assuming that you are in an area with a high gravitational potential then the gravitational force is irrelevant and General Relativity refutes your idea.

So you believe that GR is correct, that there is gravitational time dilation, but you don't believe GR? Interesting, i guess...

 

[exchemist]

Thank you! well, yeah, that is work ahead of you, not yet done, but if you want to stay at the center, you would never have to do, and are we not talking about a static situation, that exist as we measure? Using an above illustration, to push that elephant in he center room toward the surface, you need to accelerate only the rest mass not at the outset also overcome gravity.
my continuing query is: is there not really less gravity in the inside, in strength and volume than outside the surface? after all
In your work schedule, the real heavy lifting is done near the surface, not in the center.
Ps. There is way more potential work ahead of you from the surface to infinity than from the center to the surface.
final thought: would the "potential of work ahead" affect time dilation clock reading or the actual gravity strength as it is measured? to be zero?

In General Relativity, gravitational time dilation is a function of gravitational potential, not force.

So Origin is perfectly right. I quote Wiki: "The higher the gravitational potential (the farther the clock is from the source of gravitation), the faster time passes. Albert Einstein originally predicted this effect in his theory of relativity and it has since been confirmed by tests of general relativity.[1]"

From: https://en.wikipedia.org/wiki/Gravitational_time_dilation

So you could have checked it for yourself in about 30secs - if you had wanted to.

As I say, if you understood the difference between force and potential, none of us would be having this silly and apparently interminable discussion.

 

[origin]

you might have that impression, but it is off topic.(pertaining to non existing personality traits)

Your demonstrated arrogance and ignorance really is on topic, because if you accepted that you are ignorant of General Relativity and were not so arrogant as to believe that you know more about general relativity than the physicist then this thread would have ended 10 pages ago.

 

[nebel]

If you understood the difference, this "discussion" would not be necessary.

well. considering myself as a viewer, the discussion was really a good teaching experience, (being taught and teaching), mostly civil, and I still have to learn how a potential, that would not show up, when you tried to measure it could have any effect. let alone into the realm of shrinking length, and stopping movement through time.

 

[nebel]

So you believe that GR is correct, that there is gravitational time dilation, but you don't believe GR? Interesting, i guess...

During the good discussion we had, I always thought of gravity as a pull that is exerted through a given area. never as an inert possibility that is not there until you touch it.
even in the OP question reality is present not potential.
That is why your good graph has become the icon of my understanding, my reference for discussion, because it shows the actual gravity, the measurable [surface] strength, or force of gravity acting through a given area. It is real strength that gives relativistic effects. real speed "c" lets you stand still in time, real zero gravity, present only both in the center and at infinity that let clocks run free. imho, right now, still.
but let me work on it and on your graph. thank you!

 

[NotEinstein]

I was talking about just the 'g' which is zero at the centre.

Yes, you were, but as I pointed out, it's not clear nebel was.

Can you please provide some maths or reference which could confirm your point that gravitational potential is highest at the centre.

Where did I make that claim?

Please note that in Newtonian few of these quantities are derived by Gaussian method, which considers the mass inside, and in case of cantre point, the mass inside the centre is nil,

"The mass inside a point"? Since a point has zero size, this statement seems trivially true to the point of meaninglessness?

thus gravity related parameters must necessarily be zero.

What do you mean by "gravity related parameters"? Could you please list them, so I know what you are talking about?

Please clarify how potential is the highest at the centre.

Again, why should I?

 

[exchemist]

well. considering myself as a viewer, the discussion was really a good teaching experience, (being taught and teaching), mostly civil, and I still have to learn how a potential, that would not show up, when you tried to measure it could have any effect. let alone into the realm of shrinking length, and stopping movement through time.

I'm no expert on GR, but I suspect it might help if you think - in a naive picture- that light has to "climb out" of the potential well, and that is why it is the potential, rather than gravitational force at a point, that is important. But it is really to do with gravitation being equivalent to acceleration, so a lot more difficult to envisage than this.

Anyway, if you now understand the difference between gravitational force and gravitational potential, I shall consider it a good day's work for both of us.

 

[DaveC426913]

is there not really less gravity in the inside, in strength and volume than outside the surface? after all

If you would you like a meaningful answer, you'll have to start with a meaningful question.

As others have pointed out, your question is poorly formed. Gravity does not come in "more" and 'less" and does not have "volume". These misstatements are due to your desire to keep using your own ideas, instead of embracing the science.

As long as you use such inappropriate terms, you will reach faulty conclusions.

 

[nebel]

So Origin is perfectly right. I quote Wiki: "The higher the gravitational potential (the farther the clock is from the source of gravitation), the faster time passes. Albert Einstein originally predicted this effect in his theory of relativity and it has since been confirmed by tests of general relativity.[1]"

My difficulty is to reconcile his graph, with that quote. Obviously
Gravity weakens with distance from the mass thereby allowing the clock to speed. But in the graph
Gravity also weakens with with reduced radius, in conformity with the shell theorem.

light has to "climb out" of the potential well, and that is why it is the potential, rather than gravitational force at a point, that is important. But it is really to do with gravitation being equivalent to acceleration,

I can not envision the center as the lowest point in the gravity "well", short of a singularity in a BH.,yet, No, I still see a ditch representing the surface. While I can understand, that a parting particle has a long way to go against that potential,
The climb should be easy at the start, hardest at the surface, and a cinch at infinity, How can the start of the journey, the acceleration from the center be the hardest,against a maximun potential, when that center, or enclosed mass is so small, and itself generating so little gravity? Is not the greatest escape velocity at the surface? Would not that package dropped into that traverse hole through the Earth have no acceleration at the center? so, to rephrase the OP question, could we ask:
Where is more acceleration generated or required, inside an entity or out?

 

[nebel]

Gravity does not come in "more" and 'less" and does not have "volume".

amateurs, using everyday expressions, can be instrumental in better defining the phenomenon they asking questions about. The attractive force of gravity acts inside a given volume, is projected out of a surface, acts on point mass . It has more strength, or less pulling force as measured by accelerometers, gravity meters.
At this point in the discussion, which is viewed well bsw, two different pictures have developed to settle the" more outside, less inside"conflict.
a) The gravity potential: having gravity as zero at great distance, and greatest with the center of the central mass,--? do I understand that right? equations seem to treat it that way, all the gravity generating mass might as well be in the centre. and
b) Gravity as a pulling force, an acceleration. Zero at great distance, maximum at the surface of the mass and zero at the center again; reverse as you leave the mass in the other direction if you can.
No acceleration (or resistance to it ) at the center, maximum acceleration required at the surface, toward infinity there zero force again -- or another balancing situation like in the center.
I understand mass can be viewed as being all in the center, but why view gravity as being at maximum there too, as a potential, when the picture (and possible measurements) shows it should be zero?
I have yet to read an explanation for that.
Mass is treated as all being at the center only as a calculation convenience. a tool, it is not in reality. why should gravity, the effect of mass on space, follow that pattern, differ in calculation from reality?

 

[DaveC426913]

equations seem to treat it that way, all the gravity generating mass might as well be in the centre. and

It is a useful shortcut, but it is not accurate.

For example, it only applies to symmetrical bodies. Some smaller bodies are highly non-spherical, and treating them as a point mass will lead to errors.

 

[Iskcon]

Where did I make that claim?


Again, why should I?

But your response to my post implied (or it appeared to me) that you are supporting the contention that potential is highest at the centre of the earth.

Now with this post you are implying that you do not agree with this.

Can you please be more specific on this point? That is, is gravity highest at the centre of the earth or not?

 

[NotEinstein]

But your response to my post implied (or it appeared to me) that you are supporting the contention that potential is highest at the centre of the earth.

Then you misread or misinterpreted my post; please read it again. I responded mostly to your "If gravity is loosely defined as measure of g, then g is zero at the centre or am I missing something here."-statement. I said that if gravity is indeed defined that way, then you are (of course) correct. However, if it is defined as "gravitational potential" (and thus, not as g), it's not correct. At no point did I make any claims about where the potential reaches its highest point; my only claim is that the gravitational potential isn't zero at the center.

Which now has been demonstrated to be correct by other posters.

Now with this post you are implying that you do not agree with this.

I can see how one can misconstrue that from my response, but I assure you, that is not a position I hold.

Can you please be more specific on this point? That is, is gravity highest at the centre of the earth or not?

Gravity what? Force, potential, field strength? Why are you now too using the same faulty terminology that nebel uses?

 

[exchemist]

My difficulty is to reconcile his graph, with that quote. Obviously
Gravity weakens with distance from the mass thereby allowing the clock to speed. But in the graph
Gravity also weakens with with reduced radius, in conformity with the shell theorem.

I can not envision the center as the lowest point in the gravity "well", short of a singularity in a BH.,yet, No, I still see a ditch representing the surface. While I can understand, that a parting particle has a long way to go against that potential,
The climb should be easy at the start, hardest at the surface, and a cinch at infinity, How can the start of the journey, the acceleration from the center be the hardest,against a maximun potential, when that center, or enclosed mass is so small, and itself generating so little gravity? Is not the greatest escape velocity at the surface? Would not that package dropped into that traverse hole through the Earth have no acceleration at the center? so, to rephrase the OP question, could we ask:
Where is more acceleration generated or required, inside an entity or out?

Just look at the diagram in my post 319 and read once more, slowly and carefully, my explanation of why the work you need to do increases all the way in to the centre. That is what the "potential" is.

It is indeed easy at the start, hardest at the surface and progressively easier from then on out. That is exactly what the upside-down hat shape shows. Keep in mind the total climb, from wherever you start out to infinity, is what determines the value of the potential. The steepness of the slope, at any given point, is the strength of the gravitational force at that point.

So potential is one thing and force another. Force is the rate of change of potential with distance. And Potential is the integral of force over distance.