Is Gravity Caused by the Motion of Particles in the Fabric of Space?

[heusdens]

Originally posted by Mr. Robin Parsons
The manner of operation of gravity is known, only superficially, how it works inside matter, well, let's put it this way, gravity is well known for being a "Summing Force", always ADDS to itself, so my belief is probably more well founded then yours.

Gravity is a vector force. If you sum those forces up, it could give a resultant force of zero. So, you are simply wrong there!

For instance, consider a simple two body problem, in empty space.
There is exactly one point, in between the two bodies, the line that connects both centers of gravity, in which all gravitational forces are cancelled.

Now consider just a perfectly spheric object, made out of a material that has overall the same density. The force of gravity is directed towards the center of gravity, both outside the sphere and inside the sphere. Outside the sphere gravity drops proportional to 1/r^2.
Inside the gravity is proportional to r. And therefore zero at the center of gravity.

See. it could be as simply as the manner of operation permits that, if you went to the center of the earth, the Acceleration, due to Gravity, could remain the same as at the surface, and could be measured as such, if you could eliminate the counteracting thermal energy.

No, it could not. Cause when you would dig for instance 100 km. then all of the outside surface of depth 100 km, would no longer contribute to the nett force of gravity at that depth, since the combined forces of gravity cancel out each other.
Remember the are VECTOR forces, which have a direction and magnitude.

 

[Mr. Robin Parsons]

Originally posted by heusdens
Gravity is a vector force. If you sum those forces up, it could give a resultant force of zero. So, you are simply wrong there!

For instance, consider a simple two body problem, in empty space.
There is exactly one point, in between the two bodies, the line that connects both centers of gravity, in which all gravitational forces are cancelled.

Now consider just a perfectly spheric object, made out of a material that has overall the same density. The force of gravity is directed towards the center of gravity, both outside the sphere and inside the sphere. Outside the sphere gravity drops proportional to 1/r^2.
Inside the gravity is proportional to r. And therefore zero at the center of gravity.

No, it could not. Cause when you would dig for instance 100 km. then all of the outside surface of depth 100 km, would no longer contribute to the nett force of gravity at that depth, since the combined forces of gravity cancel out each other.
Remember the are VECTOR forces, which have a direction and magnitude.

That is simply what you are stating, but you have no proof of that (other then the math, and that alone is NOT proof!)

Please stop the condescentions as the person you are talking to is NOT a child!

That is what you keep saying, you can repeat it until the server dies storing the page, and that will still NOT make it any 'truer', cause, as I have repeatedly attempted to explain to you, the reality of the Earth's structure does NOT allude to a 'zero gravity state' at it's center, even though, conceptually it is the "Center Of Gravity" of the Planet.

The explanation of the 'why' of that, is currently unknown to the rest of you, I suppose, so, for now, it gets left that way.

 

[Mr. Robin Parsons]

Originally posted by heusdens
You are very very disorganised mentaly, As evidenced by your spelling?? based upon these statements.
Your very own statement was that there was no proof (which also means lack of disproof) for the center of gravity of Earth having a balancing (all force vectors of gravity, as with respect to the gravity excerted by the atoms of Earth themselves, and not the outside universe, there balance to exactly cancel themselves out, creating weithlesness at the exact center of gravity) force of gravity.

So, on other words, you now claim YOU BEEN AT THE CENTER OF EARTH AND MEASURED A NON-ZERO FORCE OF GRAVITY?NO, and NO WHERE DOES ANYONE SEE ME SAYING THAT, just you trying (stupidly) to force yourself upon me, little else...
So what was the amount of the force and direction of this force then?

It simply can't direct to any specific direction,It does, it aims for the center, what did you think it did? cause all directions would be equally likely. That just argues for why the force there should be zero.

And , please, don't come up with the quantum effects of gravity, since as we know, nothing happens inside the Earth that urges us to take into account quantum gravity! HUH? another attempt at your Hubris??!

Nuclear fusion processes, for instance, do NOT occur inside earth, And no doubt you have the proof of that too(?) neither we are on a NEUTRON star, so any out of the ordinary behaviour of gravitation is not expected inside earth.

This in fact means that all gravitational effects happening inside of earth, are no different then that happen outside of earth, which have been explored profoundly and deeply.A statement, but not a shred of proof! Quelle Idiot!

Calling upon 'Divine interventions' or the 'superatural' will not be of much help to you, to save your argument. Apparently you cannot even read, as what you seem to believe is only what you would like to see, not as I wrote, that's life!

Better start digging that hole...

Heusdens, your reflection, in a mirror..."You are very very disorganised mentaly"

As for digging a hole, already have and am easily willing/able to bury you in it!

 

[Mr. Robin Parsons]

Just a quick, passing, thought, if this "gravity all balances out to zero" hypothesis, that you would seem to be expounding as 'veritas', is in fact true, then why/how the heck is there any gravity on the planets surface?

Why isn't it zero'd out, in balance, just like you seem to wish to be doing, at it's center??

Simply question!

P.S. Sorry Heusdens for the 'Condescentions' remark, it should have been posted towards Brad_AD23, get that Brad_AD23?


Have a nice day, God willing, I will!

 

[heusdens]

Originally posted by Mr. Robin Parsons

We started the argument on this center of Earth's gravity, where Earth's gravity is effectively zero, by your statement that I have no proof of that.
You now seem to say that at the CENTER of GRAVITY the force vector of GRAVITY is directed towards the CENTER.
Unless you think that Earth's gravity has more then one center, I am perfectly able to imply that a vector force at a specfici point that directs towards the very same point, is simply zero.

And for the rest your arguments do not interest me. If you seem to think that Earth contains a nuclear reactor (where does the radiation go?) then that is just that. I don't mind whatever you belief in, as long as it makes you happy.

 

[heusdens]

Originally posted by Mr. Robin Parsons
Just a quick, passing, thought, if this "gravity all balances out to zero" hypothesis, that you would seem to be expounding as 'veritas', is in fact true, then why/how the heck is there any gravity on the planets surface?

Why isn't it zero'd out, in balance, just like you seem to wish to be doing, at it's center??

Simply question!

P.S. Sorry Heusdens for the 'Condescentions' remark, it should have been posted towards Brad_AD23, get that Brad_AD23?


Have a nice day, God willing, I will!

READ THE DAMN PROOF NEWTON GAVE FOR THIS!

 

[Mr. Robin Parsons]

Originally posted by heusdens
We started the argument on this center of Earth's gravity, where Earth's gravity is effectively zero, by your statement that I have no proof of that.

You now seem to say that at the CENTER of GRAVITY the force vector of GRAVITY is directed towards the CENTER.

Unless you think that Earth's gravity has more then one center, I am perfectly able to imply that a vector force at a specfici point that directs towards the very same point, is simply zero.

And for the rest your arguments do not interest me. If you seem to think that Earth contains a nuclear reactor (where does the radiation go?) then that is just that. I don't mind whatever you belief in, as long as it makes you happy.

You may imply anything you want, but for as long as I have known things in science, an Implication is NOT a proof!

As for the force vector at the center, it must be towards the center, and NOT zero.

The radiation is heat, and guess what, the center of the Earth is heated, radioactively heated.

When Venus had her 'makeover', back about the dawn of Homo Sapiens, it would have been a "fusile thermal eruction", probably very high energy waves, gamma perhaps, sustained, and as it flowed out of the surrounding rock, it heated the surface, in passing, giving her that nice 'un-pockmarked' face, she now has. Such an air about her as well.

 

[heusdens]

Originally posted by Mr. Robin Parsons
As for the force vector at the center, it must be towards the center, and NOT zero.

Not only you did not understand something about the proof of Newton, but now it comes up neither you undestand what a VECTOR is.

GO BACK TO SCHOOL!

Read a damn physics course book!

 

[Brad_Ad23]

Hmm I thought I suggested that learning thing.

 

[Nigel]

Aristarchus of Samos worked out the solar system theory, but the greater complexity of Ptolemy's earth-centred universe with all of its unexplained, complex epicycles was more intellectual than the facts. Mathematical junk always wins. People respect it.

If it is unintelligible, unproven, speculative, and claims to be a theory, then it will be publishable, praiseworthy, and worshipped like a religion. If it is fact, it is buried for 1000 years.

 

[Brad_Ad23]

UHHH right. Or it could just be that your idea doesn't hold any water at all for the known facts of the universe. Again as has been said, pressure gradients cannot cause the bending of light around massive objects, and your equations do not lend themselves to that at all. Nor would they be able to take into account any quantum gravity at all because they require your space to be continuous.

I can't vouch for you, but I know that all physicists have a thorough understanding of the mathematics they deal with and if it led to silly things like epicycles, it would be tossed out and couldn't make the predictions that agree with experiment as well as they do.

 

[Nigel]

Originally posted by Brad_Ad23
UHHH right. Or it could just be that your idea doesn't hold any water at all for the known facts of the universe. Again as has been said, pressure gradients cannot cause the bending of light around massive objects, and your equations do not lend themselves to that at all. Nor would they be able to take into account any quantum gravity at all because they require your space to be continuous.

I can't vouch for you, but I know that all physicists have a thorough understanding of the mathematics they deal with and if it led to silly things like epicycles, it would be tossed out and couldn't make the predictions that agree with experiment as well as they do.

Find the error in it if you claim it is wrong. There is no pressure gradient, because gravity is a pushing effect. What causes apples to fall is not a gradient in pressure. It is shielding from an all-round pressure which pushes inwards equally from all directions except those shielded by the presence of mass. Light is pushed just as an apple is.

 

[Nigel]

Originally posted by heusdens
Not only you did not understand something about the proof of Newton, but now it comes up neither you undestand what a VECTOR is.

GO BACK TO SCHOOL!

Read a damn physics course book!

No more bad language please! If textbooks are so great anyway, why do they not tell you the cause of gravity already. It would have saved me spending my life researching the subject!

 

[Nigel]

Originally posted by heusdens

Originally posted by Mr. Robin Parsons

We started the argument on this center of Earth's gravity, where Earth's gravity is effectively zero, by your statement that I have no proof of that.
You now seem to say that at the CENTER of GRAVITY the force vector of GRAVITY is directed towards the CENTER.
Unless you think that Earth's gravity has more then one center, I am perfectly able to imply that a vector force at a specfici point that directs towards the very same point, is simply zero.

And for the rest your arguments do not interest me. If you seem to think that Earth contains a nuclear reactor (where does the radiation go?) then that is just that. I don't mind whatever you belief in, as long as it makes you happy.

Great argument, but a pity that the more fundamental question of the cause of gravity is being neglected!

 

[Brad_Ad23]

Pushed by what? Light has no substance (no photons do not count as substance). Also, if this thing pushes all objects inwards, that is itself a fault. Pressure things follow certain rules, and as such somewhere in the universe there must then be a rift where there is no pressure, because an omni-directional field of pressure will create it. I can't have pressure pushing from the right, and from the left and not have some spot where the two originate where there is no pressure pushing at all.

 

[Mr. Robin Parsons]

Lets see, when you measure gravity, 'external' from the generating body, the gradient used is 1/r², when it is measured 'facially' (at the generating bodies surface) it becomes 1/r, so when you would want to measure it 'inside' the generating body, the requisite gradient would be 1/sq.rt of r, (One over the square root of 'r', so sorry I don't know how to make the square root sign!) hence you will find an 'ad reducio' factor that will permit the densities of rock that the planet has.

Gravity is a summing force, it sums all matter such that the matter will "act as one".

If you have 3 balls that are gravitationally attached to each other, a fourth ball that is gravitationally attracted to it ,is attracted to the sum of the masses of the 3 balls, not the sum of the masses reduced by factor of cancelation of gravitational energy, it doesn't work that way. Provably.

By the way Heusden, I did go to school, (high school and university [some] physics) continued studieing for years after that.

Just cause that theory made it into a movie doesn't prove that it is the right answer, just that it was the most current thought, but it does not account for the measured properties of the Earth properly, nor the measured properties of the rest of the mass in the universe, for that matter. (no pun intended?)

The center of the Earth has a very large steel ball forming in it, from the siesmic evidence, and the heat that that ball contains, would blow it apart if it were not for the generated gravitational pressure that contains it.

BTW heusdens, you state that I do not know what a 'vector' is, but if you go back in YOUR postings you used the term in the same manner as I did, so.....well, "What you see in 'others', is really the truth as it arises from within you!

Have a nice day guys!

 

[Brad_Ad23]

Dear Physics, how the hell did you guys come up with 1/r and r^-1/2?? Gravity obeys the inverse square law no matter which frame you are measuring from. It is always 1/r².

 

[Mr. Robin Parsons]

So gentlemen, this site tells of the density of the Earth, http://earth.leeds.ac.uk/dynamicearth/internal/density.htm" that helps us to know that the measurable density of the rocks must be greater within the planet as to ensure that the average density works out properly.

Further to that, as this is a physics forums, I will not need to prove this, the simple reality is that anyone who has even a slight knowledge of Fusion reactions will tell you that it requires tremendous Pressure (and temperature) to initiate.

In the theory that you seem to be expounding to me, that you would wish me to swallow a true, the center of gravity of any given gravitational object is comletely absent of any pressure what-so-ever, hence the Sun, that huge ball of firely gas in the sky, would NOT be fusing!

It could NOT be fusing as, you would want me to believe, there is NO gravitational pressure at it's center, hence it cannot be fusing.

Anyone care to try again?

Ps, please, do not try to tell me that it is "the weight of all of the material above it that is presssing down upon it" that is creating the requisite pressure, BECAUSE that weight, is only 'weight' BECAUSE of gravity!...otherwise, it would be weightless, and therefore incapable of pressuring anything!

Have a nice day guys!

 

[Nigel]

Originally posted by Brad_Ad23
Pushed by what? Light has no substance (no photons do not count as substance). Also, if this thing pushes all objects inwards, that is itself a fault. Pressure things follow certain rules, and as such somewhere in the universe there must then be a rift where there is no pressure, because an omni-directional field of pressure will create it. I can't have pressure pushing from the right, and from the left and not have some spot where the two originate where there is no pressure pushing at all.

E=mc^2. Light has energy, has mass. If you read some textbooks, you find the useful info that 'light has no rest mass'. However, since light is never at rest, that statement is about as useful as the pseudo-scientific string theory, which predicts nothing at all despite millions of dollars of funding. You think that there are no epicycles in string theory fiddling. It is all ad hoc trash. You may try to say that my work is trash on the basis that my budget comes out of my salary, and that so many people in science cannot all be wrong. In that case, you are disproven by DNA sequencing. There is not the slightest evidence that everyone in the world suddenly, in 1600, had the same mutation - preventing them from all making the same errors.

In fact, DNA evidence is that over 99.8% of human DNA data is similar. So scientifically, there is every reason why superstitions are commonplace everywhere, why mistakes are repeated, why people are over awed at things which they do not understand like tensor calculus.

Your statements about photons not constituting substance is false on the basis that radiation pressure, electromagnetic radiation pressure, has been demonstrated. The momentum of light is equal to its energy divided by the velocity of light, p = E/c. If that fact does not suggest to you that light has substance, then bye bye sir.

 

[Nigel]

Originally posted by Brad_Ad23
Dear Physics, how the hell did you guys come up with 1/r and r^-1/2?? Gravity obeys the inverse square law no matter which frame you are measuring from. It is always 1/r².

Wrong again. The gravitational potential goes as 1/r. The inverse square law is gravitational acceleration and force.

Work energy E equals the force multiplied by distance r moved in direction of the force, E = Fr. Consequently when you have gravity F = mMG/r^2, then your energy E = Fr = mMG/r.

However, this playing with potential energy, which is done in textbooks in the absence of the mechanism of gravity, is trivia.

The textbooks carry a lot of mathematical play in order to set questions with which to prepare students for exams. They do not carry the answers to fundamental questions.

Euclid's Elements of Geometry, written 300 BC, full of complex geometric diagrams and proofs, still looks impressive today. Despite the fact that Euclid made a false fifth assumption, about parallel lines reaching to infinity, which prevented general relativity being investigated for 2200 years. How impressive are textbooks?

 

[heusdens]

Originally posted by Mr. Robin Parsons
So gentlemen, this site tells of the density of the Earth, http://earth.leeds.ac.uk/dynamicearth/internal/density.htm" that helps us to know that the measurable density of the rocks must be greater within the planet as to ensure that the average density works out properly.

Further to that, as this is a physics forums, I will not need to prove this, the simple reality is that anyone who has even a slight knowledge of Fusion reactions will tell you that it requires tremendous Pressure (and temperature) to initiate.

In the theory that you seem to be expounding to me, that you would wish me to swallow a true, the center of gravity of any given gravitational object is comletely absent of any pressure what-so-ever, hence the Sun, that huge ball of firely gas in the sky, would NOT be fusing!

It could NOT be fusing as, you would want me to believe, there is NO gravitational pressure at it's center, hence it cannot be fusing.

Anyone care to try again?

Ps, please, do not try to tell me that it is "the weight of all of the material above it that is presssing down upon it" that is creating the requisite pressure, BECAUSE that weight, is only 'weight' BECAUSE of gravity!...otherwise, it would be weightless, and therefore incapable of pressuring anything!

Have a nice day guys!

We have already explained you this.

1. The force of gravity, working on all the matter of for instance the sun, cause a built up of pressure. The pressure is built up from the core to the center of gravity, cause the pressure sums up the gravity forces above it.
2. The force of gravity however runs down from the core downto the center, and becomes in the center effectively zero.

No force of gravity in the center, just means that the built up of pressure, effectively halts there. But since all matter above it feels the force of gravity, this means that the pressure there is at the maximum. And not zero.

The pressure is just the sum of gravitational forces of all matter above a certain point.

 

[Brad_Ad23]

Ah, misreading. The gravitational potential energy, yes that is 1/r. The gravitational force, is 1/r². They way it was said, it sounded as though we were still talking bout the force when Parsons said 1/r inside bodies. And actually he was referring to force. So my post is correct.

 

[Mr. Robin Parsons]

Originally posted by heusdens
We have already explained you this.

1. The force of gravity, working on all the matter of for instance the sun, cause a built up of pressure. The pressure is built up from the core to the center of gravity, cause the pressure sums up the gravity forces above it.
2. The force of gravity however runs down from the core downto the center, and becomes in the center effectively zero.

No force of gravity in the center, just means that the built up of pressure, effectively halts there. But since all matter above it feels the force of gravity, this means that the pressure there is at the maximum. And not zero.

The pressure is just the sum of gravitational forces of all matter above a certain point.

If the pressure halts at the center, then No fusion.

If the gravity runs down to zero, then no matter, if matter, the no zero cause matter generates gravity...period.

If you do a shell game of matter, you find that the matter on the outer shell well exceeds the amount of matter towards the middle, hence if your scenerio worked there would be no matter at the center, it would be hollow. (it isn't!)

Aside from that, as I have pointed out, mathematically you can find a zero point, but in reality there is none, because gravity is the pressurization of both energy, and matter, by matter.

The core of the Earth is a large steel ball, pressurized by gravity and heated by the pressurization that gravity generates.

Further to that gravity, as I have pointed out, is a part of a thermal cycle that absorbs energy, the graity part, and shortwaves (compresses) it to thermal+ wavelengths, which re-emits as heat, from the center.

In order for that to occur, gravity must hold sway right to the very center of the core of the earth.

In order for your scenario to work, the greatest pressure would be at the half way point, which makes no sense, what-so-ever. Aside from that, it will not account for the rock density problems that we know are real.

Believe whatever you want, but remember the 'Sunshine' as that is the proof that I have that, fusion takes place there, in the center of the core of the Sun.

BTW if the force of gravity runs down towards the center, then the density of the rock, would have the greatest densities of rock at the surface, which, last time I, or anyone else, looked, IS NOT THE CASE!

There is also the cases of core colapse in Steller Novas, wouldn't happen if the center was at zero as the rest of the matter flies off of the surface due to the thermal expunging on energy while the core remains intact.

P.s. it is the core collapse that generates the expunging heat, so how can the core, with a zero g center, initiate the colapse?

Explain please...cause I don't think you can cause your responce is wrong! (only works in the movie not in reality!)

Brad, 1 over the square root of r, inside.

 

[Brad_Ad23]

Not quite sure how you get a shell. There will be more matter above it, but remember, this is 3d so there is just enough across it to counteract the pull it feels above it. It still sums out to zero.

 

[heusdens]

Originally posted by Mr. Robin Parsons
If the pressure halts at the center, then No fusion.

If the gravity runs down to zero, then no matter, if matter, the no zero cause matter generates gravity...period.

If you do a shell game of matter, you find that the matter on the outer shell well exceeds the amount of matter towards the middle, hence if your scenerio worked there would be no matter at the center, it would be hollow. (it isn't!)

Aside from that, as I have pointed out, mathematically you can find a zero point, but in reality there is none, because gravity is the pressurization of both energy, and matter, by matter.

The core of the Earth is a large steel ball, pressurized by gravity and heated by the pressurization that gravity generates.

Further to that gravity, as I have pointed out, is a part of a thermal cycle that absorbs energy, the graity part, and shortwaves (compresses) it to thermal+ wavelengths, which re-emits as heat, from the center.

In order for that to occur, gravity must hold sway right to the very center of the core of the earth.

In order for your scenario to work, the greatest pressure would be at the half way point, which makes no sense, what-so-ever. Aside from that, it will not account for the rock density problems that we know are real.

Believe whatever you want, but remember the 'Sunshine' as that is the proof that I have that, fusion takes place there, in the center of the core of the Sun.

BTW if the force of gravity runs down towards the center, then the density of the rock, would have the greatest densities of rock at the surface, which, last time I, or anyone else, looked, IS NOT THE CASE!

There is also the cases of core colapse in Steller Novas, wouldn't happen if the center was at zero as the rest of the matter flies off of the surface due to the thermal expunging on energy while the core remains intact.

P.s. it is the core collapse that generates the expunging heat, so how can the core, with a zero g center, initiate the colapse?

Explain please...cause I don't think you can cause your responce is wrong! (only works in the movie not in reality!)

Brad, 1 over the square root of r, inside.

You are constantly confusing two distinct things: gravity and pressure.

Like I said, pressure is building up from the core to the center.
But this building up is actually getting slower as you get deeper, cause the force of gravity there, decreases, down to zero.
THAT MEANS THAT ALL THE WAY DOWN, PRESSURE INCREASES. The maximums pressure is at the center. Becase there, the CUMULATIVE force of all the matter on which gravity acts, is excercised.

Why don't you just look up Newton's proof of this? It simply shows that the shell above a certain radius r, excerts a force of gravity which exactly cancels out, and therefore the net force of gravity is equal to the force of the mass of radius r.

 

[Mr. Robin Parsons]

Heusdens, if at any pont the gravity is equal to zero, and there is pressure then it blows up, explodes, fracures out into lots of little pieces, gravity is what is holding it all together, by pressurization.

Newton did NOT know about Neutrons, Neutron Stars, Black Holes, The Big Bang, The currently known size of the Universe, The rest of the Galaxies out there, Stars using fusion as their source of power, Nuclear reactions, A bombs, H bombs, the internal structure of the Earth, the huge stell ball that is there, as measured, (RECENTLY!) He did not know a lot of the things that get taught in High School Science classes, right now.

I did the shell game calculation and it is very clear that if the gravity drops, off then the Earth IS hollow, and it Ain't! as there cannot be pressure, on matter, absent of gravity, as all of the pressurizations you see, anywhere, are a direct, and indirect, result, of what gravity, in atoms, does, NO exceptions!

Without the pressure that only gravity can cause, the heat (anti-pressure)there, would blow it apart!

Nigel, if your spatial pressurization, as per surface area worked, then I could take a 1 square meter piece of material, 1 mm thick, and find a ten fold difference, in it's weight, as per gravities pressurization on it, simply by standing it on it's edge, as opposed to laying it flat.

Sorry to tell you, it doesn't work that way, and that, too, is provable!

 

[Brad_Ad23]

Parsons, think about it for a minute. At this center point where gravitational vectors sum to zero, what do you have above it in every direction? Why the Earth of course. Since all the gravity vectors sum to zero at this point, that means (as is correct) all this mass above this point is wanting to fall inward. After all, that is where gravity makes it want to go. So you have this enourmous weight pushing down on the center of gravity, and then you have the outward pressuer and heat which do what kiddos? Why it supports the Earth's enourmous weight. Wow, the Earth doesn't blow apart ater all.

 

[Nigel]

Originally posted by Brad_Ad23
Parsons, think about it for a minute. At this center point where gravitational vectors sum to zero, what do you have above it in every direction? Why the Earth of course. Since all the gravity vectors sum to zero at this point, that means (as is correct) all this mass above this point is wanting to fall inward. After all, that is where gravity makes it want to go. So you have this enourmous weight pushing down on the center of gravity, and then you have the outward pressuer and heat which do what kiddos? Why it supports the Earth's enourmous weight. Wow, the Earth doesn't blow apart ater all.

At the centre of the earth, there is no net push from the fabric of space in any direction. In other words, in the middle a person is equally shielded by the Earth isotropically (in all directions).

Gravitation is not an attractive effect. The acceleration of objects towards each other is due to their mutual shielding, although a person's shielding of the Earth is insignificant conpared to the Earth's shielding of a person, so in effect only the Earth is doing significant shielding when you consider falling people and apples. This is why a person's or apple's mass does not affect their acceleration, which is 9.8 ms^-2 or 32 feet/sec^2 on the surface.

At the very middle, a hypothetical point of no size, there is no net force or acceleration in any direction.

A pulling effect (I believe as shown by my proof that gravity is pushing, not pulling!) would depend entirely upon the difficult physical problem of whether or not two opposing vectors cancel each other out, or whether the net effect simply becomes undetectable by some ways of measurement.

Dr Arnold Lynch PhD and David A. Chalmers BSc did some research on examples of "field cancellation" problems. Dr Lynch points out that where you get radio wave interference, you can find points where there is zero measurable field strength, although clearly the energy does not vanish. Another example is electromagnetic gamma ray radiation. It has a net field of zero, because its positive and negative fields along the wave oscillation exactly balance. Therefore, as a whole it is uncharged. However, you can detect gamma rays and they deliver energy. Dr Lynch worked on the problems of microwave radiation interference for British Telecom in the 1980s and his work is published in Proc. IEE. Standing waves, where reciprocating energy is passing through itself in bouncing around, creates null points called "nodes". Energy passes through these.

David Chalmers worked with lasers on the problem of energy conservation in Young's double slit experiment. The problem is that when you measure the total energy on the screen in the double slit experiment, and compare it to energy conservation in the water tank double slit experiment as Young did, you find an anomaly. Interference can mean that light arriving out of phase cancels to produce dark fringes, but the energy is still there in the maths! In other words, equal light arrives on the bright and dark areas in the double slit experiment, but the dark areas are dark because the electromagnetic fields of the light rays cancel out. At least, that is what one version of the mathematical energy conservation equation has us believe. It is probably more complex.

If two vectors cancel, that may mean either that there is nothing at all, or that there is something still, yet what remains has no net result. If however you take the case of a person, then you are not dealing with an infidesimal point at the centre of the earth. In that case, you need to make detailed calculations for the forces to the arms and legs. However, this whole argument is a leap away from the basic issue of the cause of gravity, which needs to be resolved.

 

[Nigel]

Originally posted by heusdens
You are constantly confusing two distinct things: gravity and pressure.
...

Why don't you just look up Newton's proof of this? It simply shows that the shell above a certain radius r, excerts a force of gravity which exactly cancels out, and therefore the net force of gravity is equal to the force of the mass of radius r.

Newton's proof that there is no net gravity acting on an infidesimal point anywhere inside a hollow sphere or shell requires the inverse-square law of gravity to cancel out the geometry of the situation.

The fact that gravitational potential energy, E = Fd = (mMG/d^2)d = mMG/d, is inversely proportional to distance, not to the square of distance, seems to raise a problem with Newton's proof. While the forces on a single infidesimal point anywhere within the shell will "cancel out" (i.e., they may not cease to exist, but at least they balance from all sides), the gravitational potential energy would vary with location within the shell.

IF you moved, you would therefore be subject to a force to due to changes in your gravitational potential energy, which is not predicted in analyses of the shell problem. In other words, you only feel no net force if you are so small you do not exist, and you do not move at all. Since all atomic electrons, etc., are always in motion you have forces right away to a person in such a situation.

The major issue is probably the reduction of all-round inward directed space pressure, when inside a shell which shields you from all directions. In that case, even if there was an equality of forces to a static point, the overall compressive force will be reduced. It will be like the difference between the 14.7 pounds per square inch (101 kilopascal) pressure of air at the Earth's surface. if you go into space without a pressurised spacesuit and only with a bottle of compressed air, you would soon notice that the vector cancellation of air pressure forces from all directions at sea level did not mean that there was no scalar air pressure. The effects of the reduction in pressure would not be pleasant (diver bends, rupture of delicate tissue in lungs, inflammation of blood vessels under skin, etc.).

Therefore, when vectors cancel, scalar components do not have to, and there can be all kinds of complicated effects. Probably the most interesting would be to use a hollow sphere as a time-machine, because of the effects on space-time of being at reduced space pressure. But I only want to get gravity's cause sorted out at this stage.

 

[icespeed]

sorry nigel, yell at me if this is really obvious or already been answered.

you analogised your theory to the wind rushing the other way when someone walks down a corridor, or air rushing to fill a suitcase that's been opened.
so that's like saying spacetime rushes past the accelerating galaxies to provide pressure that we feel as gravity.
so... where does all the spacetime from beyond the accelerating galaxies come from?