A Weighty Topic

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The other night I initiated a short debate with my niece by asking a simple question.  I’d like to pose this question for debate here on Writerbeat and then see how this might lead to a much weightier discussion.  The simple question was this:  How much do you think you would weigh at the center of the earth?

 

After agreeing to ignore such problems as how one might get there and avoid being incinerated by molten iron she decided that your weight would be so great that you would be crushed.  I acknowledged that her answer seemed obvious but that I thought you would actually be weightless.

 

My explanation was that weight is simply the attraction that mass has upon another object. At the center of the earth, all of the earth’s mass would be equidistant from you and any directional attraction would be cancelled out by an equivalent attraction from the exactly opposite direction.  All of this is predicated, for argument’s sake, that the earth is uniform in composition throughout.

 

The idea of being weightless at the center of the earth is hard to conceptualize, I believe, because we live on the surface where all of earth’s mass is either directly or radially below us.  All of our experiences and frames of reference are surface oriented.  If I tried to model this, for example, and created a 100 foot sphere of iron on earth’s surface I would be crushed at the center.

 

Now I will admit that I have no formal training in physics but my musings lead to a question that perhaps one of you on Writerbeat may be able to answer. Physicists know that the majority of a star’s fusion occurs at the core where the greatest pressures exist.  The pressures, apparently, are not caused by the cumulative weight of the outer parts of the star but by the incredible density of the core itself.  But what gives?  Wouldn’t the core itself experience equidistant opposing gravity?  If so then could this imply that the great pressures of continual nuclear fusion are held from normal rate expansion by the core’s tremendous density leading to further fusion in a feedback loop until all of the hydrogen is consumed?

 

This all hurts my brain but trying to understand what’s going on inside the beltway is worse.  Maybe I should try Keeping Up with the Kardashians.

Comments

Dino Manalis Added Jun 26, 2018 - 3:48pm
 What difference does it make?  The center of the Earth is for lava, not human beings!
James E. Unekis Added Jun 26, 2018 - 3:58pm
Dino, probably.  But then again, how do we know?   ;-)
James Travil Added Jun 26, 2018 - 6:25pm
I'm for the weightless theory. As for stars fusion occurs from the tremendous pressure of the overall mass, not gravity per say. At least that is what I have surmised. As a side note you certainly have some interesting conversations with your niece! Of course my nieces are 5-7 years old so I can't quite relate. 
James E. Unekis Added Jun 26, 2018 - 6:34pm
Thanks for the comments James.  I've read about stars a bit but it just gets deeper and deeper.  I would be interested in the formation of black holes; some threshold is exceeded there for sure.
 
Yea she is 21 and we stray from "normal" conversation at times.  It keeps things interesting.
Mustafa Kemal Added Jun 26, 2018 - 7:17pm
James, interesting fun with your niece.
 
It is clear that the center would be weightless. But I suspect this form of weightlessness is much different than being in outer space with no mass nearby. Here all the mass is pulling you outward very strongly with cancelling vectors.  any perturbations from perfect would produce a force on you outward( negative weight!). I suspect the gap in the discussion is related to
 
" The pressures, apparently, are not caused by the cumulative weight of the outer parts of the star but by the incredible density of the core itself."

With all those outer layers being attracted to the mass on the antipodal  I suspect that that this attraction provides much pressure on the core increasing its density.
 
So, now in weightless state at the center and any perturbation produces negative weight the postive weight of the outer shells toward the center should combine to produce interesting dynamics.
 
Mustafa
 
Jeff Michka Added Jun 26, 2018 - 7:40pm
I like the weight of Elvis on the Sun @ 7140 lbs.  LOL
Mustafa Kemal Added Jun 26, 2018 - 8:57pm
But Jeff, on Pluto, he would be 13 lbs. can you imagine his performances?
 
Elvis on Mars
 
James E. Unekis Added Jun 26, 2018 - 10:30pm
Mustafa,
Thanks for the feedback.  I still suspect that a star, without perturbation, should produce weightlessness at it's exact core.  Of course a star without disturbances wouldn't be a star so I guess it doesn't really matter.
James E. Unekis Added Jun 26, 2018 - 10:39pm
Mustafa, Jeff,
 
Elvis will always be with the stars!
Bill H. Added Jun 26, 2018 - 10:53pm
Mustafa - On Pluto at minus 350 degrees F, he certainly wouldn't be a Hunka Hunka Burnin' Love.
Leroy Added Jun 26, 2018 - 11:11pm
You might be weightless, but you would be crushed by the pressure.
Mustafa Kemal Added Jun 26, 2018 - 11:16pm
Bill H,
re:"On Pluto at minus 350 degrees F, he certainly wouldn't be a Hunka Hunka Burnin' Love."
LOL thanks
Digress Added Jun 27, 2018 - 12:02am
I have more WEIGHTY concerns that affect life and my existence. Chickens and eggs, or trees falling in a forest are for those with little concern for life!
Ward Tipton Added Jun 27, 2018 - 2:17am
But what about all the hidden civilizations that exist there? Would we not be infringing or at least intruding on their reality? 
Mark Hunter Added Jun 27, 2018 - 3:21am
Yes, I think we'd be weightless at the center, if we could survive it. I think. Obviously it's not possible, but I still love speculation like this.
James Travil Added Jun 27, 2018 - 4:23am
" Obviously it's not possible, but I still love speculation like this."
Then you "have little concern for life"! According to Mr. "Digress". But I digress... 
Mark Hunter Added Jun 27, 2018 - 6:03am
Yeah, I like both chicken and eggs, especially scrambled eggs, and I love walking in the forest.
Of course, another possibility is that people have room in their heads for both the important and the fun.
James E. Unekis Added Jun 27, 2018 - 11:55am
Bill,
 
Too funny.  Yea, but he still might be a hunk of chiiling ice for some of his fans.
James E. Unekis Added Jun 27, 2018 - 12:03pm
Leroy,
Thanks for your comment.  Interesting.  My head is kinda of shaking in agreement one minute and then disagreeing the next.  Where would the pressure come from without the force of gravity?
James E. Unekis Added Jun 27, 2018 - 12:17pm
Digress,
 
Thanks for your feedback.  I'm, sorry that you didn't appreciate my post.  I will point out that my abstract thinking has led to some very pragmatic solutions to problems in industry as well as state government.
James E. Unekis Added Jun 27, 2018 - 12:21pm
James,
 
I'm glad you enjoyed the speculation.  I'm not sure how Mr. Digress determined that I have little concern for life but he's entitled to have an opinion.
James E. Unekis Added Jun 27, 2018 - 12:34pm
Mark,
 
Thanks for your comments.  I believe that the world needs a balance of thinkers.  A mix of pragmatists, innovators, theorists, artists, etc., often beats a completely homogeneous group on solving issues that really matter.
 
Now which came first, scrambled eggs or the omelette? 
Atom Rider Added Jun 27, 2018 - 1:37pm
Am I the only genius in the room? You weigh exactly the same as you do anywhere else! Like Mars, it's not your weight, it's the gravitation force upon your matter.
James E. Unekis Added Jun 27, 2018 - 1:46pm
Atom,
weight, as a measurement of gravity's attracting force upon an object does indeed changed.  This was proven when humans landed on the moon.  What remains constant is your mass.  Maybe we are saying the same thing in different words.
Atom Rider Added Jun 27, 2018 - 1:52pm
Sup James, lol, yes, I agree. I should have put a coma or period after, "You weigh exactly the same." It would have made the joke more clear.
James E. Unekis Added Jun 27, 2018 - 3:01pm
Atom,
Sorry buddy - I missed your intended humor.  I've got a bit of brain fog today.
 
Wayne McMichael Added Jun 27, 2018 - 4:02pm
Gravity is not an attracting force, it is a pushing force... like water going down a drain. Dense matter is like a black hole lite, and gravity pushes into that. I "think" you would get heavier to a point, but not sure where that point would be:)
James E. Unekis Added Jun 27, 2018 - 5:00pm
Wayne,
 
Interesting point, I've never thought of it in those terms.  Still, if jump out of an airplane it seems that I would be pulled towards the gravity of the earth and not pushed up back away from it, right?
Wayne McMichael Added Jun 27, 2018 - 6:05pm
James E. Unekis pushed toward the biggest black hole:) Magnetism comes from the opposite end of the scale. That is why we can use that to counter gravity... meaning if you block gravity, then you are in a different dimension. Gravity defines this dimension. Infinite Wave Theory:)
James E. Unekis Added Jun 27, 2018 - 6:21pm
Wayne,
Thanks, I'll have to read up on that.
Leroy Added Jun 27, 2018 - 6:33pm
"Leroy,
Thanks for your comment.  Interesting.  My head is kinda of shaking in agreement one minute and then disagreeing the next.  Where would the pressure come from without the force of gravity?"
 
If mass attracts, then all the mass around you is attacting itself towards the center.  It is like the walls are closing in on you from all sides.  I'm no astrophysist, but I believe that would explain why planets are round, thereabouts. 
Autumn Cote Added Jun 27, 2018 - 7:22pm
Please note, it's against the rules to post more than one article within a 48-hour period.  
Richard Plank Added Jun 27, 2018 - 7:32pm
JEU, when you do the math the answer is zero as you surmised.  But it really is not that is what you feel if you could do this.  Your weight does not change, but because gravity is zero you feel like zero.  And that even assumes the mass of the earth is evenly spread out which I suspect it is not so close to zero is probably what you would feel.  Sorry not my expertise, been a long time since my year of Physics in high school.
Mark Hunter Added Jun 27, 2018 - 9:26pm
"Now which came first, scrambled eggs or the omelette?"
 
Um ... let's see .... if it's in the center of the Earth, the omelette would make itself first. But if you were on the surface where there's gravity, the scramble would be easier.
wsucram15 Added Jun 27, 2018 - 10:00pm
Im not a physics major either but it is an interesting question.  Weight changes by location...mass does not. You literally weigh more ath the north pole than you do at the equator.
I have to agree with Leroy..zero weight but extreme pressure. At least that is the understanding I have. For example, the deeper you go under the water the more the pressure, its why we cant go the the bottom of the ocean .  Apparently it is much easier to go into space than towards the center of the earth.  I think the record is held by a Russian experiment for deepest depth towards center of the Earth. 
opher goodwin Added Jun 28, 2018 - 1:56pm
Wow!! That's an interesting one. I'd go for weightless but crushed and melted.
Jeff Jackson Added Jun 28, 2018 - 3:50pm
As far as we know, the center of the moon is solid, in that it does not have the molten core like the earth. The center of the earth is most likely molten because it has 360 degrees of pressure all around it. As you go deep (and we've gone pretty deep) the temperature of the rocks gets warmer and warmer. Can't say as I have experienced this, as I like it just fine up here on the surface, thanks.  I would tend to believe that star cores are molten for the same reason as earth's and that is that the pressure all around is super-heavy. But the more important question: Is the gravity greater at the center of the Death Star?
Even A Broken Clock Added Jun 28, 2018 - 4:45pm
Armchair physicist here. You definitely would be at the bottom of the gravity well for the earth. The escape velocity is determined at earth's surface by the force (weight) exerted on an object at that point. For those of us on the surface, you basically can consider the mass of the earth to be a centered at a point directly below you, since the mass of the atmosphere above you is insignificant. But if you were in that hollow tube that extends through the earth (imaginary tube), falling down through the center of the earth, close to the surface, back through the center, back near the surface, ad infinitum till you came to rest in the center of the earth, you would essentially be weightless. The mass that causes earth's gravitational field would be distributed spherically around you. Therefore the gravity from earth's gravitational field would be zero at the center of the earth. You would still be subject to gravitational fields from the sun, and our galaxy, but in our everyday experience, it is the earth's field that is orders of magnitude stronger.
 
Now if you were to try to climb out of the center, you would find it a much more difficult task because you are going to fight the entire mass of the earth as you climb to the surface.
James E. Unekis Added Jun 28, 2018 - 5:15pm
Richard,
 
Thanks for the comment.  I think that weight does change but mass never changes - I could be wrong.    The mass of the earth is certainly NOT evenly spread out.  This is theoretical assuming earth as a sphere, uniform in material and distribution throughout.  Sometimes non experts open doors of thought simply because they can be more open to possibilities.
James E. Unekis Added Jun 28, 2018 - 5:16pm
Mark,
 
I would eat it here or there, I would eat it anywhere.  lol
James E. Unekis Added Jun 28, 2018 - 5:24pm
wsucram15,
Thanks for the comment.  I always cringe when I see your comments because my brain always changes your user name to SCRAM.  Lol
 
I believe the water theory doesn't apply because, like my 100 foot sphere of iron example, it is a surface phenomena.  Even the depths of the ocean exists comparatively on the surface.  Perhaps trapped gases would provide crushing pressure but this would be an effect of compression and not gravity.  Thanks for the heads-up on the Russian.  I'll need to read up on that.
James E. Unekis Added Jun 28, 2018 - 5:27pm
Opher - thanks for commenting.  Yea, for argument's sake I'm not taking in the realities of heat.  My question would remain, if there is no gravity whence comes the pressure?
James E. Unekis Added Jun 28, 2018 - 5:34pm
Jeff, thanks.  I'm still trying to wrap my head around where the pressure comes from in an area of canceled gravity.  I don't think star cores are molten, I believe they are super-compressed plasma.
Ha ha - the death star?  It was supposedly moon sized so....?
James E. Unekis Added Jun 28, 2018 - 5:36pm
Even a broken clock - thanks for the feedback.  You did a good job o summarizing what I was trying to get to.  Is it just one of the two times a day?
Atom Rider Added Jun 28, 2018 - 6:32pm
Can I change my answer? I say, you are not 100% weightless. You would have some measure of weight. One thing I haven't seen is is the topic of centrifugal and centripetal forces, or maybe i missed it. Even though, you would still only be making one rotation per day, and one orbit per year around the sun, there are minuscule forces there. Your hands would pull away from each other with centrifugal force upon the mass. In order to be 100% weightless you would have to eliminate those forces as well. Even though you are at the center of the earth, you are still in orbit around the sun, and the milky way, and so on. If you were a subatomic particle in a Buddha sphere of light at the center of the universe without rotation and perfectly still, you could maybe levitate in the 4th dimension, therefore, beyond space and time and no longer on Earth, and also, achieve the status of space cadet. If the Earth and the Sun and the Milky Way are all part of the equation, the answer is.......weight for it......=>0! L0L
James Travil Added Jun 28, 2018 - 7:14pm
"But the more important question: Is the gravity greater at the center of the Death Star?"
The answer is no, because all of the gravity in the Death Star is artificial and generated from it's southern most point. Thus all gravity is evenly pulling towards that southern area not towards the center of the space station. I know this because I've read a lot of books about Star Wars and that universe. 
James E. Unekis Added Jun 28, 2018 - 8:32pm
Atom rider,
very true.  I suppose I should have qualified my whole article to eliminate rotational and other minute forces which exist in many forms.  Good catch!
James E. Unekis Added Jun 28, 2018 - 8:35pm
James,
 
Thanks for the clarification on he death star.  My only Star Wars knowledge was from seeing the original in the 1970's.
 
Let the force be with you.
Leroy Added Jun 29, 2018 - 8:29am
"I suppose I should have qualified my whole article to eliminate rotational and other minute forces which exist in many forms."
 
Perhaps we should define weight.  We all know that it is mass times acceleration but you don't feel the weight unless there is an opposing force, such as the surface of the earth.  This opposing force creates pressure.  If you jump out of an airplane, you don't feel your weight.  If you are inside an airplane and it is accelerated towards the earth the same as your body, you get the feeling of weightlessness.  You are still experiencing acceleration.  We often associate weightlessness with being in space.  You would not be weightless on the space station.  In fact, your weight would not be all that different than on earth.  It is more like being in a plane accelerating towards the earth; you are perpetually falling.
 
If we assume that we are weightless at the center of the earth and there is pressure from all sides, we would not feel weightless.  In fact, we would feel as though we were being crushed by weight from all sides.  Would the centrifugal forces technically change what we feel as weight in a weightless environment?  It would be so minute compared to the crushing force of mass attracting from all sides.  If we were standing on a scale in the center of the earth in a hollow tube, would it register anything?  We have mass and acceleration, but we don't have pressure on our feet.  Would we be forced to one side of the tube?  No.
Ward Tipton Added Jun 29, 2018 - 9:27am
Actually, in accordance with the almost cliche Energy equals Mass times the speed of light squared ... assuming of course that the speed of light is a constant ... which it is not ... but again, a different article ... mass does change ... though generally only as you approach the speed of light ... now how fast are we hurtling through space on this rock while safely tucked away in our meat covered skeletons? Probably not that fast? 
 
That being said, pressures change underground as they do in the water, though not as substantially ... if you can fathom such a concept ... pun intended. While pressure would not necessarily increase your mass ... it would certainly make you feel like you weigh more ... at least until it crushed you completely. 
James E. Unekis Added Jun 29, 2018 - 10:24am
Leroy,
I'm confusing my own self as I contemplate all of the variables.  I can kind of see where one might be crushed but I can also see where you might be pulled apart. 
 
I believe that people on the space station ARE weightless although I am not completely sure.
 
I need to do some more reading and call my brother who has a little formal physics training.
 
I do appreciate your insights ! 
James E. Unekis Added Jun 29, 2018 - 10:35am
Ward,
Yes, you are right, thanks for the correction.  As an object approaches the speed of light it approaches infinite energy as well.  This is the same as an increase in mass.
 
I don't think using water pressure is fair because even at the depths of the Mariana Trench it would still represent basically a surface model with the great majority of earth's mass still below it.
Katharine Otto Added Jun 29, 2018 - 11:29am
James,
I think it would depend on where you place the scale, but I agree with your latest thought that gravity would be around you and more likely to pull you apart than exert pressure.
 
The idea that gravity curves space and time leads me to wonder if the earth, planets, stars, and galaxies are just clumps of gravity.
 
The reference to the center of stars being under enormous pressure and very dense reminds me that black holes have similar properties, but we don't tend to think of them as spherical.
 
Also, the earth is also a giant magnet, with north and south poles.  What effect might electromagnetic forces have at the center of the earth?  Poor Einstein never succeeded in finding that unified field theory.  Maybe you are on to something, here.
James E. Unekis Added Jun 29, 2018 - 1:03pm
Katharine,
Thanks for your response.
 
Yes, I guess scale placement would have some effect - it certainly does in my bathroom - lol.
 
Sure, anything with mass has gravity - so since planets, stars and galaxies have mass they certainly are clumps of gravity.
 
I suspect that the center of every star is either a small black hole or is approaching a black hole.  A black hole is so dense that the mass of an entire solar system might take up the space of, say, a tablespoon.
 
Another possibility is that a black hole exists at the center of every galaxy.  This might explain the spiral shape of so many galaxies; much like the very low pressure a the eye of a hurricane causes a spiral as the surrounding higher pressure air competes to fill the hole.
 
I couldn't begin to speak of the effects of electromagnetic forces at the center of the earth except to speculate that if the center of the earth is indeed "weightless", and the greatest pressures actually lie somewhere between the surface and the center perhaps that is where a circle of molten iron exists.
 
Unified field theory?  Thanks for the compliment but I'm afraid that their is too much weightlessness between my ears to ever take on something s complex - lol. 
 
 
opher goodwin Added Jun 29, 2018 - 2:19pm
Too many forces at work. Gravity is a weak force. It would not pull you apart because the force of the material around you creating immense pressure would be too great.
James E. Unekis Added Jun 29, 2018 - 2:42pm
Opher,
Thanks for the comment.
Assuming 0 or close to 0 gravity, what would cause the pressure?  Again, I suspect that we have a hard time with this because all of our experiences and understanding is surace based.
 
If you lay between a steel plate and a military tank, it would crush you.  If you did so in space, you'd be fine.
 
I also think that one needs to look at gravity as an attracting force - we are pulled towards the floor by the gravitational pull of earth's mass instead of being pushed down by our own mass.  
 
I think I could make a better case that someone would be pulled apart than crushed.
 
All that said, I do value your opinions since I have no formal training in physics.
Stone-Eater Added Jun 29, 2018 - 2:46pm
Dino
 
The center of the Earth is for lava, not human beings!
 
As far as we know the center is an iron core. And believe me, you'd probably weigh a ton and wouldn't survive a minute :-) BTW: If there were no gravity forces in the core (which is quite small in diameter compared to the rest - remember the earth crust is about 30 km only in general...) how could the rest be kept together ?
 
Take the chair you sit on. If there were no gravity forces it would dissolve itself - and you too :-)
 
https://www.scientificamerican.com/article/what-if-there-were-no-gravity/
 
I mean nobody knows for sure. 
 
http://theconversation.com/if-atoms-are-mostly-empty-space-why-do-objects-look-and-feel-solid-71742
 
Schrödinger's cat LOL
Stone-Eater Added Jun 29, 2018 - 2:48pm
Oph
 
It would not pull you apart. It would squeeze you to needle pin size (I believe) :-)
James E. Unekis Added Jun 29, 2018 - 5:37pm
Stone-eater,
 
Thanks for your comment.
 
Isn't it possible that the earth's integrity is sort of an exoskeleton that slowly weakens as you approach the core?
Leroy Added Jun 29, 2018 - 8:56pm
"I believe that people on the space station ARE weightless although I am not completely sure."
 
The may feel weightless, but they are not, no more than they are weightless than they are inside a plane accelerating towards earth.  The force of gravity is inversely proportional to the square of the distance between two objects.  If at point A you weighed W, then at twice the distance, you would weight one-quarter W.  The earth's radius is about 3,959 miles.  The space station orbits about 250 miles above the earth, thereabouts.  Someone on earth who weighed We would weight Ws on the space station:
 
Ws = We*(3,959/(3959+250)^2 = 0.885*We
 
That's far from weightless.
James E. Unekis Added Jun 29, 2018 - 9:50pm
Leroy,
 
I hope I'm not being dense.
 
OK, I hear you about the space station but I think that the .885*We is cancelled through centrifugal forces caused by their high speed in maintaining orbit.
 
On training planes where they dive to simulate space conditions, the occupants float through the plane for the 45 or so seconds that they are diving.  They have mass and inertia but wouldn't move the scale if they were to step on it.
 
Isn't that weightless?
 
 
wsucram15 Added Jul 1, 2018 - 11:02pm
interesting feed, seems others have had this idea.. check on the Russian team, cannot remember the name, but that was done on land and they got down I think  a few miles and it was too hot to go further. 
Leroy Added Jul 2, 2018 - 10:43am
I hope I'm not being dense."
 
Not at all.  Concepts have changed since I was taught physics. 
 
"OK, I hear you about the space station but I think that the .885*We is cancelled through centrifugal forces caused by their high speed in maintaining orbit."
 
Would you believe that there are no centrifugal forces involved?   I've heard it described as continually falling towards earth and missing the target.  There's no contact force, so there is no feeling of weight.  If you are whirling an object on a string, there is a centripetal force towards the center.  There is a reactive, pseudo force (centrifugal force) pulling on the object in the opposite direction.   If you were inside the object, you would be slung against the wall.  When in orbit, there is only a centripetal force in the direction of the center of mass.  If there were a centrifugal force, you would be thrown to the side of the space station.  The height of the orbit is dependent on the object speed.  An equilibrium is established with the gravitation pull that keeps the object in orbit.
 
"On training planes where they dive to simulate space conditions, the occupants float through the plane for the 45 or so seconds that they are diving.  They have mass and inertia but wouldn't move the scale if they were to step on it.
 
Isn't that weightless?"
 
It goes back to my previous post in how we define weight.  Some say that gravity is the force pushing up.  If that is true, then you would be weightless if there is no contact force.  You certainly don't feel your weight if there is no contact force, such as the surface of the earth.  On the other hand, if you do feel the pressure, such as in the center of the earth, is that necessarily weight?  It would certainly feel like you were being crushed by weight.
The Burghal Hidage Added Jul 9, 2018 - 9:33pm
EABC - Liked your explanation. Put more simply, if one is at the core one in essence becomes a part of the earth's mass. Yes?
James E. Unekis Added Jul 9, 2018 - 9:52pm
Burghal,
Yes I agree.  EABC illustrated his point well by using a hollow tube or straw.
The Burghal Hidage Added Jul 9, 2018 - 10:13pm
Indeed he does. he's a right smart one, that guy :)
Doug Plumb Added Jul 9, 2018 - 10:23pm
Your weight would be zero, your mass would be unchanged. You would experience gravity in all directions and therefore the net effect would be zero. You would get bigger because the air wouldn't have gravity to push it into you. Air pressure would be zero.
Doug Plumb Added Jul 9, 2018 - 10:27pm
Maybe you would explode and blood and guts would create a mess.
James E. Unekis Added Jul 10, 2018 - 2:01am
Doug,
It is 2:00 A.M. and snorted out loud at your last comment.  Maybe one would explode after all.  Thanks for the laugh. 
Leroy Added Jul 10, 2018 - 9:00am
I was playing with magnets last night.  Magnets have some similarities to gravity in that the force of attraction is inversely proportional to the square of the distance between the magnet and the object, thereabouts.  It seems obvious to me that if you were caught between two powerful magnets, one north and one south facing, you would be crushed.  It is much like a mass that attracts other mass.  Indeed, if we search the internet, we find that there is great pressure at the center of the earth, according to science.
 
I took a steel ball and place it between two north-south facing magnets.  As I moved the magnets towards the ball, it stayed stationary.  If I removed one magnet, the ball would immediately move to the other magnet.  If I assumed mass worked in a similar matter, the object would be weightless at the center of the earth.  As I brought the magnets closer and closer together, it was difficult to maintain this equilibrium.  The ball would forcefully move towards one magnet or the other.  The ball is obviously being pulled from both sides.  The closer to the magnet, the greater the force of attraction.  Any smaller error upset the equilibrium.  If we assume it works in a similar way with mass, the mass closest to us has the greatest attraction.  I can test this by stacking magnetic disks.  As I add disks, the force of attraction becomes greater but the additional attraction diminishes with each additional magnet.
 
So, it brings up another interesting question.  Rather than Clock's cylinder, let's supposed you were in a sphere at the center of the earth.  We can pressurize it to satisfy Doug.  Wouldn't you be pulled in all directions?  Wouldn't you have to fight the force of gravity just to bring your arms together?  The net forces would be close to zero in the center.  If you got too close to the wall, wouldn't you be stuck to it?  If you get just a little off center, it would seem that you would be quickly and forcefully drawn to the closest side and stuck there for eternity.  Wouldn't you feel weight?  Inquiring minds want to know.
James E. Unekis Added Jul 10, 2018 - 1:16pm
Leroy,
Thanks for the interesting comment.  I must admit that, although I am fascinated by magnets, I have never studied how the earth's magnetic fields behave....so I was just dealing with gravity.  I suspect that the magnets you were dealing with are just too far off scale to compare to a human inside the earth - but as I am writing this I could indeed imagine a few atoms of iron behaving in the same way as your little ball.  I honestly don't know but I sense something is off in using these magnets to test the center of the earth theory.
 
Scientists may postulate great pressure but I am not sure that they have ever tested it.  Maybe they have mathematically modeled it, but models always make assumptions.  Still, I have no expertise, just a curious mind.
 
In the case of bringing your arms together you would have to assume that the left half of the earth would only pull on your left arm and the right half of the earth only on your right arm, correct?
 
Why would the right half of the earth not be pulling with (nearly - to adjust for the minor proximity of a few feet) force on your left arm?  
 
The funny things is that I don't think we will ever know for sure.  Still I applaud you for your abstract thinking - it is much appreciated.

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