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Author Topic: When does gravity begin to affect the inner core of a mass ?  (Read 5210 times)

tommya300

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When does gravity begin to affect the inner core of a mass ?
« on: 12/08/2010 15:17:09 »
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I understand roughly that accretion of matter is an accidental collisions and collection of gases, dust and larger debris.
As this matter begins to collect, there is a point that gravity starts gaining precedents.
I also remember that, I think it was said, "that gravity is a weak force?"
I realize that all the elements have different melting points.

At what point does the gravity exert enough of pressure to begin a cascade in melting the solid core to this semi liquid state?
Or was the primary elements having a low melting point, matter went from a gasous state to a liquid state before becoming solid?
Or was there a mix of all the 4 states including, plasma, the semi liquid/solid?

As the core begins to melt the heat expands things, where is the exhaust relief?
Is it through the fishers of the collection of the debris from accretion?
As you measure closer to the surface from the core, the pressure and heat reduce, and what point would there be a noticeable difference to being a solid?
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« Last Edit: 12/08/2010 16:03:54 by tommya300 »

frethack

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When does gravity begin to affect the inner core of a mass ?
« Reply #1 on: 12/08/2010 16:19:03 »
I understand roughly that accretion of matter is an accidental collisions and collection of gases, dust and larger debris.
As this matter begins to collect, there is a point that gravity starts gaining precedents.
I also remember that, I think it was said, "that gravity is a weak force?"

Not necessarily "accidental".  Van der Waals forces and electrical forces begin the accretion.  And yes, gravity is weak when compared to the Strong Force and electromagnetism.  A small magnet has no trouble lifting a nail against gravity, even though the earth is millions of times more massive than the magnet.

At what point does the gravity exert enough of pressure to begin a cascade in melting the solid core to this semi liquid state?
Or was the primary elements having a low melting point, matter went from a gasous state to a liquid state before becoming solid?
Or was there a mix of all the 4 states including, plasma, the semi liquid/solid?

As the core begins to melt the heat expands things, where is the exhaust relief?
Is it through the fishers of the collection of the debris from accretion?
As you measure closer to the surface from the core, the pressure and heat reduce, and what point would there be a noticeable difference to being a solid?

The inner core is not semi liquid...it is solid, but the outer core is liquid.  Are you looking for an exact gravitational force in Newtons or a more qualitative answer?

tommya300

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When does gravity begin to affect the inner core of a mass ?
« Reply #2 on: 12/08/2010 23:02:59 »
Quote
Not necessarily "accidental".  Van der Waals forces and electrical forces begin the accretion.  And yes, gravity is weak when compared to the Strong Force and electromagnetism.  A small magnet has no trouble lifting a nail against gravity, even though the earth is millions of times more massive than the magnet.

Is it like static electricity, like a static clinging action we experience from a clothes dryer, but stronger then what we experience, due to the confined area, where the electical attractive force accelerates the bodys or debris into each other?

Quote
The inner core is not semi liquid...it is solid, but the outer core is liquid.  Are you looking for an exact gravitational force in Newtons or a more qualitative answer?
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I should of know of course, what was I thinking. It is solid how else can the generation of the magnetic field exist.
I would say qualitative.
Sorry! I realize now the twist of my questions. The amount of pressure to create the heat needed to melt, which element, to many variables, it is rediculous to ask, find that info online.

Rephrase new question:
The relation of presure when you get to the center inner core, does it become lesser because gravity starts to work against itself the closer you get to the center?

Would the solid inner core be a percentage in size, of the exterior overall size entire body mass?

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« Last Edit: 12/08/2010 23:20:14 by tommya300 »

frethack

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When does gravity begin to affect the inner core of a mass ?
« Reply #3 on: 13/08/2010 01:49:53 »
Is it like static electricity, like a static clinging action we experience from a clothes dryer, but stronger then what we experience, due to the confined area, where the electical attractive force accelerates the bodys or debris into each other?

Something like that, yes.  The beginnings of accretion are thought to be from static electricity.  Ill see if I can find this video, but a shuttle astronaut was playing with styrofoam (I think it was styrofoam) in a plastic bag, and the pieces would immediately begin to clump together under zero G.  Van der Waals forces are thought to be at work as well, which are the same forces that hold muscovite sheets together and give viscosity to liquids with large molecules.

I should of know of course, what was I thinking. It is solid how else can the generation of the magnetic field exist.
I would say qualitative.

Actually, the magnetic field is generated in the liquid outer core.  I work in a paleomagnetics lab, but I am a novice when compared to the others there.  Ill ask for a paper the comprehensively explains the magnetic field and post it here if youd like.  Basically, the field is created by the roughly circular (or cylindrical) eddies that are churned up in the liquid core by the rotation of the solid inner core.

Rephrase new question:
The relation of presure when you get to the center inner core, does it become lesser because gravity starts to work against itself the closer you get to the center?

Would the solid inner core be a percentage in size, of the exterior overall size entire body mass?

The vector for gravitational force is continually toward the center of mass, so gravity doesnt begin to work against itself as you approach the center.  Theoretically, the exact center of a large mass should have infinite gravity because gravitation force has an inverse square relationship to the radius of your point of interest.

mMG/√r is the gravitational force equation.
m = mass of object 1 in kg
M = mass of object 2 in kg
G = gravitational constant = 6.673x10-11 m3kg-1s-2
r = radius in m

That is the reason that the inner core is solid.  Gravity creates enough pressure to overcome ~9000C temperatures, and creates a bimodal liquid/solid core.
« Last Edit: 13/08/2010 01:56:58 by frethack »

tommya300

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When does gravity begin to affect the inner core of a mass ?
« Reply #4 on: 13/08/2010 03:54:26 »
Quote
Actually, the magnetic field is generated in the liquid outer core.  I work in a paleomagnetics lab, but I am a novice when compared to the others there.  Ill ask for a paper the comprehensively explains the magnetic field and post it here if youd like.  Basically, the field is created by the roughly circular (or cylindrical) eddies that are churned up in the liquid core by the rotation of the solid inner core.

I do not know if I will understand the details of a paper from there, where you feel that your a novice in compared to the others. It would be disapointing having you go through all that trouble to find out the end result, me not understanding it. I am not saying yes or no.

Is it similar to this item when I google spherical magnet?

http://complex.umd.edu/dynamo/3m.html

Quote
mMG/√r is the gravitational force equation.
m = mass of object 1 in kg
M = mass of object 2 in kg
G = gravitational constant = 6.673x10-11 m3kg-1s-2
r = radius in m

That is the reason that the inner core is solid.  Gravity creates enough pressure to overcome ~9000C temperatures, and creates a bimodal liquid/solid core.

As (r) goes to zero the reciprical is infinity, I see this.
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« Last Edit: 13/08/2010 04:09:50 by tommya300 »

frethack

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When does gravity begin to affect the inner core of a mass ?
« Reply #5 on: 13/08/2010 04:42:55 »
Here is a link describing the astronauts experiments.  He was a space station astronaut and the mediums were sugar, salt, and coffee grounds instead of styrofoam.  Also, I should clarify myself by saying that the center point of a large gravitational force is theoretically infinite, though this is probably not the case.

http://www.skyandtelescope.com/news/3308986.html?page=1&c=y

And yes, that is one of the leading teams researching the geodynamo
« Last Edit: 13/08/2010 04:45:32 by frethack »

tommya300

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When does gravity begin to affect the inner core of a mass ?
« Reply #6 on: 13/08/2010 16:30:07 »
Quote
Actually, the magnetic field is generated in the liquid outer core.  I work in a paleomagnetics lab, but I am a novice when compared to the others there.  Ill ask for a paper the comprehensively explains the magnetic field and post it here if youd like.  Basically, the field is created by the roughly circular (or cylindrical) eddies that are churned up in the liquid core by the rotation of the solid inner core.

I do not know if I will understand the details of a paper from there, where you feel that your a novice in compared to the others. It would be disappointing having you go through all that trouble to find out the end result, me not understanding it. I am not saying yes or no.

Is it similar to this item when I google spherical magnet?

http://complex.umd.edu/dynamo/3m.html

Quote
mMG/√r is the gravitational force equation.
m = mass of object 1 in kg
M = mass of object 2 in kg
G = gravitational constant = 6.673x10-11 m3kg-1s-2
r = radius in m

That is the reason that the inner core is solid.  Gravity creates enough pressure to overcome ~9000C temperatures, and creates a bimodal liquid/solid core.

As (r) goes to zero the reciprocal is infinity, I see this.
.

Wait a second, I was just thinking.
If the radius goes to zero then the area of that radius goes to zero.
Without area, how can there be any matter?
If there is no matter, how can there be a mass?
Without mass, how can gravity exist at that point?

so to satisfy the form at r=0

mMG/√r ----> (0/0), not infinity

As we approach zero, for small "m", we begin to reduce the (MG) mathematically, by the direct relation of the fraction of "m"

so since "r" becomes smaller, the ratio of the "mMG" follows.

Is there something I am missing here?

I do not think that this form (mMG/√r) can apply here.
Because the radius of the inner and outer is not attracted to each other in the sense, since they do not have a differential distance apart, the distance measuring from an individual center of each mass. I think of the relations as an orbital attraction of two individual bodys seperated apart.
.

.
Why are you using a square root of(r).
I tried to find a source that would reflect your exact expression I can not find any except here. Can you direct me to a reliable resource link.
« Last Edit: 13/08/2010 17:33:31 by tommya300 »

frethack

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• Posts: 394
When does gravity begin to affect the inner core of a mass ?
« Reply #7 on: 13/08/2010 16:38:03 »
I am forgetting the shell concept, that as you descend into a body, the overburden no longer exerts gravitational force.  So you are correct in the beginning, that as you descend, gravity begins to cancel, though the overburden still exerts pressure.

One of the physics guys may have a better explanation if they happen to come across this thread.  And I should have had r2 in the denominator...thanks for posting the correct equation.
« Last Edit: 13/08/2010 17:35:54 by frethack »

tommya300

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When does gravity begin to affect the inner core of a mass ?
« Reply #8 on: 13/08/2010 17:41:23 »
I am forgetting the shell concept, that as you descend into a body, the overburden no longer exerts gravitational force.  So you are correct in the beginning, that as you descend, gravity begins to cancel

One of the physics guys may have a better explanation if they happen to come across this thread.  And I should have had r2 in the denominator...thanks for posting the correct equation.

Thanks for you response! You did get me to see things and investigate subject matter, so all this is just fine.
My questions through out this thread were a bit twisted up, it may never get anyone elses attention.
As I read my questions, after I get some sleep, I see things different in all my posts.
Sometimes I can not believe I said things or  presented things that way, in some cases.
Like it were someone else. What little sleep can do.
.
« Last Edit: 13/08/2010 17:50:52 by tommya300 »

imatfaal

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When does gravity begin to affect the inner core of a mass ?
« Reply #9 on: 13/08/2010 17:55:50 »
Within a solid sphere the gravitational attraction varies linearly with distance from the centre - when you reach the centre the gravity is not infinite it is zero.  This could be thought of as an extreme case of the shell theorem.  the shell theorem of gravity states that within a symmetrical spherical shell no gravity is felt by any object inside  - newton proved this with chunky calculus and gauss in another way (thats really neat but  I cannot remember at present).  pressure is another matter entirely; just because you are not experiencing an net attraction to the centre of mass doesnt mean that the pressure on you is zero

tommya300

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• Posts: 655
When does gravity begin to affect the inner core of a mass ?
« Reply #10 on: 13/08/2010 22:15:52 »
Within a solid sphere the gravitational attraction varies linearly with distance from the centre - when you reach the centre the gravity is not infinite it is zero.  This could be thought of as an extreme case of the shell theorem.  the shell theorem of gravity states that within a symmetrical spherical shell no gravity is felt by any object inside  - newton proved this with chunky calculus and gauss in another way (thats really neat but  I cannot remember at present).  pressure is another matter entirely; just because you are not experiencing an net attraction to the centre of mass doesnt mean that the pressure on you is zero

Mat I have a question concerning this pressure at exactly center of a somewhat solid in nature, not an enpty shell, sphere. as the earth.
At exactly zero center there is zero area if it is zero area what unit of measure would be attached to this pressure?

If it, the idea, was a little off center then wouldn't it mathmatically satisfy a unit of measure?

Maybe there is no real ideal center because of a spinning unbalanced wabble of the inner most sphere, like in a washing machine spin cycle with a offset load of clothes ? Where the measured center is being banged or hammered at by a pressure from all directions, not all at once, but, from time to time?

If so can this wabble gain amplitude over many years, like feedback and flip over swapping magnetic poles?

« Last Edit: 13/08/2010 22:32:21 by tommya300 »

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When does gravity begin to affect the inner core of a mass ?
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