Hollow Earth, Hollow Gravity

I have just finished reading a very detailed book that has half convinced me that the earth (and other planetary bodies) are hollow. I know this sounds ridiculous, and if someone here gives a good answer why not, I’ll change my mind, (and get very annoyed that I read a 500 page page book that can be disproved!) but I can’t think of a good reason to disprove it.
I read the previous topic on this site on the hollow earth theory, but no-one raised the points that were in this book so I’ll have a go.

You can see the book at: http://www.amazon.com/gp/reader/0620...15#reader-link , its written by Jan Lamprecht who says the book is a Lateral Thinking exercise along the lines advocated by Kurt Godel.

When I started reading I had three problems I could see with the hollow earth concept;
1. Gravity
2. Seismology
3. The origin of volcanoes

I found his rebuttals to these points hard to flaw, which he answered in the very first section:

1. Newton's Law of Gravity; one of the most useful mathematical formulae ever devised. This little formula has made space travel and the exploration of the Solar System possible. It made satellites possible. . . . Scientists use this little formula to gain an understanding of galaxies far away, and indeed the behaviour of the universe as a whole. It is now more than 300 years since Newton devised this little formula; and we still do now know what causes gravity.
Newtonian gravity is accurately measured and proven with the bounds of the solar system. However, Newtonian gravity remains untested in other areas. All we have is a formula. This formula has been used to determine the mass of the Earth. This is based on the concept that for each mass of M inside the Earth, it exerts and attractive force of F. We do not know the valid range for Newtonian gravity. Inside Newton's formula is G. G is the "universal gravitational constant". It is assumed, and assumed is the correct word here, that each mass of M exerts the same force of F regardless of where in the universe it may be placed. It is also assumed that each mass of M exerts the same force F whether it lies on the surface of the Earth or whether it be deep inside the Earth. When using the Cavendish balance to determine the mass of the Earth, it is assumed that each particle exerts a fixed force upon all others. This assumption rules out the very real possibility that particles near the surface of a planet might exert a force greater than those deep down. The key to all of our gravity is the mass of the Earth. If the mass of the Earth is wrong, then so are our estimates for those of other bodies. If the mass of the Earth has been overstated, then it follows that the masses of all other bodies in the solar system have also been overstated. If the Earth is hollow, then so too is every other planet in the solar system.
How can we be sure that the Earth really has the mass accorded it by Newtonian gravity? As gravity is so unbelievably weak, is an experiment using two lead balls really representative of the entire Earth? No, of course not. There is electrical charge to account for, and also magnetic forces and electromagnetic forces, that are a lot stonger than gravity, that the current theory does not take into account.
[He then proceeds to go into detail about Newton’s shell theorem, which is too mathematically complex for me to understand, but I think proves that gravity is always 0 at the centre of any spherical body]

..then seismology

2. The only "reliable" method we have of knowing what goes on in the Earth beneath our feet comes from the science of Seismology. However, there are many examples of actual findings being different from what was predicted. The science of seismology contains two very broad assumptions which no one has ever been able to verify: 1. The speed of seismic waves beneath the Earth is ultimately inferred from our understanding of the structure of the Earth based on Newtonian Gravity. We have no way of being certain that these waves really are reaching these depths or travelling at these speeds. 2. We cannot be sure that speed changes are due to the changing constitution of the Earth. Our view of the inner Earth might be very skewed. Much of the predicted structure changes have never turned out to be real. If we find such errors at depths of just a few kilometres, how much less can we trust our ideas when dealing with rock which is hundreds and perhaps thousands of miles beneath the surface?
The fact that the deepest man has ever gone into the earths crust is 25 miles, theres still hundreds of miles to go until we can have any sort of proof.

..then geology

3. What do we really know about the Earth's interior? And how trustworthy is our knowledge of it? Many people (mistakenly) think that the lava which pours out of volcanoes comes from a large reservoir of molten material which makes up the greater part of the Earth. Scientists have discovered that lava comes from within the Earth's crust. The lava comes from approximately 20 miles down. The existence of lava does not affect the passage of earthquake (seismic) waves. This indicates to scientists that the crust is largely solid. So where does the heat come from which melts the rock locally? Scientists have advanced two theories. Some say that the melting is due to high concentrations of radioactive elements in a particular area. These decaying radioactive elements generate enough heat to melt rock. Much lava is slightly radioactive and that lends support to this theory. Other geologists have argued that shearing and faulting are adequate heat generating mechanisms via friction. The evidence supports both theories. Lava cannot possibly be rising from the centre of the Earth as some may be tempted to think. It would cool down and become solid on its long, slow journey upwards. Lava is therefore a surface phenomenon and does not in any way reflect what the Earth is like 50 or 100 or more miles down.

The author then gives some reasons to believe the earth may be hollow. He mentioned what seismologists call the 'shadow zone' which is the large area in the centre of the earth that no P or S waves ever penetrate, and he has concluded that it is more likely that they cannot penetrate that because there is nothing there to penetrate (seismology does not work in gas). He also explains the earth’s magnetic field with a counter rotating dynamo effect which involves a burning hydrogen core. He postulates that as Hydrogen is the lightest element, due to Newton’s shell theorem making g = 0 at the centre, it would naturally diffuse to the centre and would burn in a reaction similar to the suns.

I was surprised to read a review of the book from Dr Tom Van Flandern (astronomer, formerly U.S. Naval Observatory) who said: “For merely showing us all that the inferred density profile of Earth's interior is not a unique solution of seismic data -- an important constraint for all theoreticians working in that area -- the book had already made itself worthwhile.”
And also a review from Richard Baum (Director Mercury & Venus Sections, British Astronomical Association) which said: “I must say you have stored your book with an enormous amount of information; much quite surprising, all stimulating. Essentially you are not only obliging us to take a fresh look at things but to observe from an unsuspected different position - the presumed impossible.”

It all sounded quite scientifically sound to me, so I decided to put it in this debunking section, as I can’t debunk it, especially the points 1, 2, 3 he makes.

Is there anything that really puts a nail in all this theory? i'd be eager to hear it.

 PhysOrg.com science news on PhysOrg.com >> 'Whodunnit' of Irish potato famine solved>> The mammoth's lament: Study shows how cosmic impact sparked devastating climate change>> Curiosity Mars rover drills second rock target
 How did the earth come to be hollow then? It is rather implausible that the earth was somehow formed that it is, or has been, or will be hollow.

 Quote by bel How did the earth come to be hollow then? It is rather implausible that the earth was somehow formed that it is, or has been, or will be hollow.
That is a valid point, but he did cover that

You would have the centripetal force from the spin, and he says magnetism from pole to pole may affect the interior formation. There is also Electrical current which have been proven to flow through the earth which may affet the interior.

The current theory, of gradual accumulation of mass from asteroids and dust, does not really explain how the huge reaction at the centre started in the first place, or how it is sustained.

He says that over time as the earth accumulated more mass it grew more circular as the strength of gravity increased, and when bodies form into circular bodies, as Newtons shell theorem says (http://en.wikipedia.org/wiki/Shell_theorem), gravity starts to cancel out directly in the centre, and the planet forms into a hollow structure. Architects havce already proven the structure is sustainable, like a Dyson Sphere (http://en.wikipedia.org/wiki/Dyson_sphere) or a Globus Cassus (http://en.wikipedia.org/wiki/Globus_Cassus)

Hollow Earth, Hollow Gravity

 Quote by ZeuZ It is assumed, and assumed is the correct word here, that each mass of M exerts the same force of F regardless of where in the universe it may be placed. It is also assumed that each mass of M exerts the same force F whether it lies on the surface of the Earth or whether it be deep inside the Earth.
The assumption of translational symmetry is one of the most basic assumptions of physics without which physics is generally meaningless. If this assumption is challenged, other physical laws should not be invoked to further an argument. And Newton's theory of universal gravitation follows from $$F=ma$$.

 i dont think he is saying we need to challenge translational symmetry at all, he is pointing out that there are other forces that affect particles apart from gravity and all of these forces are infact much stronger than gravity, so they may infact play a much bigger role than gravity does in planetary formation. In other words its not just the mass of particles that affect their formation, its also the charge and other local electromagnetic forces. He also suggests that gravity may invert, which would put the center of gravity as a ring around the crust, and objects inside the cavity will be attracted out to the crust aswell as objects outside the crust. i'm not so sure about 'inverting gravity', i can see gravity cancelling at the centre, but not fully inverting like he suggests.
 Mentor If the earth was hollow, then wouldn't that hugely affect the orbit of the earth around the sun, and the moon around the earth? What ever happened to Occams Razor? Given what we know about planet formation, it is a lot more likely that the earth has matter inside it than it is hollow.

Mentor
 Quote by ZeuZ I’ll change my mind, (and get very annoyed that I read a 500 page book that can be disproved!)
You should be annoyed, but withyourself as well as the author. Why did you waste your time on this tripe? I'm not going to spend a whole lot of time debunking this, but here goes.

 When I started reading I had three problems I could see with the hollow earth concept; 1. Gravity 2. Seismology 3. The origin of volcanoes
That's a good start. Add the Earth's magnetic field, cosmology, Occam's scalpel, ...

 Newtonian gravity is accurately measured and proven with the bounds of the solar system. However, Newtonian gravity remains untested in other areas. All we have is a formula. This formula has been used to determine the mass of the Earth.
First, Newtonian gravity is not exactly correct. General relativity is a better model, and it works exactly as it does here as far as we can see. That bit about not knowing whether gravity works outside the solar system is the purest of BS.

We also have the density of rocks and the size of the Earth which serve as a very good check on the Earth's mass as deduced by satellite orbits and the moon's orbits. If the Earth ws hollow, it would have to be made of something much denser than rock to account for orbits.

The Earth is very, very small compared to the sun. The Earth's mass contributes almost nothing to the orbits of the other planets. Their orbits are independent checks against the value of the universal gravitational constant based on observations of the moon and satellites.

Finally, the gravitational attraction inside the supposed hollow earth would be zero. Supposed inhabitants inside the hollow earth would live in a near zero-g environment.

 ..then seismology
THe author is completely full of it here. A hollow earth would have a very distinct seismological ring. We use seismological data to "see" to the core of the Earth. Either siesmologists have conspired to cover-up the hollow earth, or the author is lying.

 ..then geology
More BS. Please read up on the incredible amounts of science that describes how our earth was formed and how we know about the inside of the Earth.

 Quote by bel And Newton's theory of universal gravitation follows from $$F=ma$$.
You aren't helping. Newton's theory of universal gravitation does not follow in any way from Newton's laws of motion.

Mentor
 Quote by ZeuZ That is a valid point, but he did cover that You would have the centripetal force from the spin...
Clearly, the centripetal force could not create a spherical shell, since it is nonexistent at the poles. It could only ever create a doughnut-shaped body, like the rings of Saturn. But like rings, such things are typically gravitationally unstable and tend to collect into single, solid bodies (aka, moons).

Regarding his other issues with gravity:
 The key to all of our gravity is the mass of the Earth. If the mass of the Earth is wrong, then so are our estimates for those of other bodies. If the mass of the Earth has been overstated, then it follows that the masses of all other bodies in the solar system have also been overstated. If the Earth is hollow, then so too is every other planet in the solar system.
Correct - therefore the calculated mass of the earth could not possibly be wrong. You can't have a hollow gas giant (or sun, for that matter), and we've sent space probes to every planet and many, many moons. Obviously, our understanding of gravity must be correct.

I love self-debunking crackpots!

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 Quote by ZeuZ 1. Newton's Law of Gravity; one of the most useful mathematical formulae ever devised. This little formula has made space travel and the exploration of the Solar System possible. It made satellites possible. . . . Scientists use this little formula to gain an understanding of galaxies far away, and indeed the behaviour of the universe as a whole. It is now more than 300 years since Newton devised this little formula; and we still do now know what causes gravity. Newtonian gravity is accurately measured and proven with the bounds of the solar system. However, Newtonian gravity remains untested in other areas. All we have is a formula. This formula has been used to determine the mass of the Earth. This is based on the concept that for each mass of M inside the Earth, it exerts and attractive force of F. We do not know the valid range for Newtonian gravity. Inside Newton's formula is G. G is the "universal gravitational constant". It is assumed, and assumed is the correct word here, that each mass of M exerts the same force of F regardless of where in the universe it may be placed. It is also assumed that each mass of M exerts the same force F whether it lies on the surface of the Earth or whether it be deep inside the Earth. When using the Cavendish balance to determine the mass of the Earth, it is assumed that each particle exerts a fixed force upon all others. This assumption rules out the very real possibility that particles near the surface of a planet might exert a force greater than those deep down. The key to all of our gravity is the mass of the Earth. If the mass of the Earth is wrong, then so are our estimates for those of other bodies. If the mass of the Earth has been overstated, then it follows that the masses of all other bodies in the solar system have also been overstated. If the Earth is hollow, then so too is every other planet in the solar system. How can we be sure that the Earth really has the mass accorded it by Newtonian gravity? As gravity is so unbelievably weak, is an experiment using two lead balls really representative of the entire Earth? No, of course not. There is electrical charge to account for, and also magnetic forces and electromagnetic forces, that are a lot stonger than gravity, that the current theory does not take into account. [He then proceeds to go into detail about Newton’s shell theorem, which is too mathematically complex for me to understand, but I think proves that gravity is always 0 at the centre of any spherical body]
All this proves is that Jan Lamprecht is ignorant of the physics necessary to write this book. Newtonian Gravitation is not accurate with the Solar System - even GPS satellites rely on General Relativity.

 ..then seismology 2. The only "reliable" method we have of knowing what goes on in the Earth beneath our feet comes from the science of Seismology. However, there are many examples of actual findings being different from what was predicted. The science of seismology contains two very broad assumptions which no one has ever been able to verify: 1. The speed of seismic waves beneath the Earth is ultimately inferred from our understanding of the structure of the Earth based on Newtonian Gravity. We have no way of being certain that these waves really are reaching these depths or travelling at these speeds. 2. We cannot be sure that speed changes are due to the changing constitution of the Earth. Our view of the inner Earth might be very skewed. Much of the predicted structure changes have never turned out to be real. If we find such errors at depths of just a few kilometres, how much less can we trust our ideas when dealing with rock which is hundreds and perhaps thousands of miles beneath the surface? The fact that the deepest man has ever gone into the earths crust is 25 miles, theres still hundreds of miles to go until we can have any sort of proof.
This is almost entirely misinformation. The speed of seismic waves have been computed with little or no recourse to "Newtonian Gravity". The speed of these waves have been experimentally measured and the numbers agree with the theory. Furthermore, in the last couple of decades, people have used this same technique to calculate phonon velocities in multilayered semiconductor materials, which agree excellently with experimental measurements.

References:
Lord Rayleigh, Proc. London Math. Soc. 17, 4 (1887)
K. Sezawa and K. Kanai, Bull. Earthquake Res. Hist. 17, (1939)
J. G. Scholte, Proc. Acad. Sci. Amsterdam 45, 20 (1942)
R. A. Phinney, Bull. Seismol. Soc. Am. 51, 527 (1961)
W. Pilant, Bull. Seismol. Soc. Am. 62, 285 (1972)
I. V. Ponomarev and A. L. Efros, Phys. Rev. B 63, 165305 (2001)

 ..then geology 3. What do we really know about the Earth's interior? And how trustworthy is our knowledge of it? Many people (mistakenly) think that the lava which pours out of volcanoes comes from a large reservoir of molten material which makes up the greater part of the Earth. Scientists have discovered that lava comes from within the Earth's crust. The lava comes from approximately 20 miles down. The existence of lava does not affect the passage of earthquake (seismic) waves. This indicates to scientists that the crust is largely solid. So where does the heat come from which melts the rock locally? Scientists have advanced two theories. Some say that the melting is due to high concentrations of radioactive elements in a particular area. These decaying radioactive elements generate enough heat to melt rock. Much lava is slightly radioactive and that lends support to this theory. Other geologists have argued that shearing and faulting are adequate heat generating mechanisms via friction. The evidence supports both theories. Lava cannot possibly be rising from the centre of the Earth as some may be tempted to think. It would cool down and become solid on its long, slow journey upwards. Lava is therefore a surface phenomenon and does not in any way reflect what the Earth is like 50 or 100 or more miles down.
This is also completely nonsensical. Measured lava temperatures (from hundreds of volcanoes) range from about 650C to about 1200C. Temperatures in the Mantle are estimated to be about 900C. There's no reason for magma (I sure hope the author didn't call it 'lava', 'cause then he'd also be revealing his ignorance of middle school geography) to cool significantly below this temperature on its way up.

 The author then gives some reasons to believe the earth may be hollow. He mentioned what seismologists call the 'shadow zone' which is the large area in the centre of the earth that no P or S waves ever penetrate, and he has concluded that it is more likely that they cannot penetrate that because there is nothing there to penetrate (seismology does not work in gas). He also explains the earth’s magnetic field with a counter rotating dynamo effect which involves a burning hydrogen core. He postulates that as Hydrogen is the lightest element, due to Newton’s shell theorem making g = 0 at the centre, it would naturally diffuse to the centre and would burn in a reaction similar to the suns.
More crackpottery! For one thing, the gravitational field is zero everywhere inside the hollow - not just at the very center. Secondly, to burn hydrogen in a thermonuclear reaction (like in the sun) you need a mass of at least 8% the mass of our sun. The mass of the earth is itself about 50,000 times too small. And if you believe in a hollow earth, then it's even smaller still.

See: Very low mass stars, black dwarfs and planets

 I was surprised to read a review of the book from Dr Tom Van Flandern (astronomer, formerly U.S. Naval Observatory) who said: “For merely showing us all that the inferred density profile of Earth's interior is not a unique solution of seismic data -- an important constraint for all theoreticians working in that area -- the book had already made itself worthwhile.”
Dr. van Flandern, once a respectable astronomer, is now a Relativity denying conspiracy theorist.

 And also a review from Richard Baum (Director Mercury & Venus Sections, British Astronomical Association) which said: “I must say you have stored your book with an enormous amount of information; much quite surprising, all stimulating. Essentially you are not only obliging us to take a fresh look at things but to observe from an unsuspected different position - the presumed impossible.”
This is an excerpt from a private email to the author who seems to have a personal relationship with R M Baum - it a not a public review.

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 Quote by ZeuZ ..then geology 3. What do we really know about the Earth's interior? And how trustworthy is our knowledge of it? Many people (mistakenly) think that the lava which pours out of volcanoes comes from a large reservoir of molten material which makes up the greater part of the Earth. Scientists have discovered that lava comes from within the Earth's crust. The lava comes from approximately 20 miles down. The existence of lava does not affect the passage of earthquake (seismic) waves. This indicates to scientists that the crust is largely solid. So where does the heat come from which melts the rock locally? Scientists have advanced two theories. Some say that the melting is due to high concentrations of radioactive elements in a particular area. These decaying radioactive elements generate enough heat to melt rock. Much lava is slightly radioactive and that lends support to this theory. Other geologists have argued that shearing and faulting are adequate heat generating mechanisms via friction. The evidence supports both theories. Lava cannot possibly be rising from the centre of the Earth as some may be tempted to think. It would cool down and become solid on its long, slow journey upwards. Lava is therefore a surface phenomenon and does not in any way reflect what the Earth is like 50 or 100 or more miles down.
This fellow hasn't studied geology past high school, and even then probably wasn't paying attention.
He's right that there isn't (much) melted material in the deep earth, but this should surprise no one (I'll forgive the fact that he called it lava, when the correct term is magma. Lava is an eruptive product and is only called that on the surface). The mantle is a plastically deforming solid (think silly putty) and does not melt due to the extreme pressure on it. I don't know where he gets his ideas of what scientists say* causes lava melt, but he's fairly far off the mark. For the major causes, firstly, yes heating is an option, but not from localised radioactive decay or faults, but from convecting material upwelling from the core-mantle boundary. Secondly, decompression of material at ocean ridges, continental rifts etc allows melting. Thirdly, addition of volatiles like at subduction zones can lower the melting point of the mantle.
Let's think about his claim that lava (magma!) rising from the core would cool and set. Firstly, barring perhaps some amount of magma at the ultra low velocity zone next to the outer core, as I've already said the mantle is largely solid and deforms as a plastic. This material setting is irrelevant. If it were a liquid, S-waves would be unable to penetrate it, and yet they do. Again, he doesn't know what he's talking about. As for a hot plastically deforming solid rising, that is plausible. The earth is a very poor conductor of heat, and it so conduction is a very slow method of removing heat from the core. Since the mantle can behave as a fluid, convection therefore is the major way in which heat is transferred. Seismology, by the way can in fact pick up columns of low density material rising up through the mantle...

I'm not at all sure how he feels this is evidence for a hollow earth anyway... What does it have to do with it?

 The author then gives some reasons to believe the earth may be hollow. He mentioned what seismologists call the 'shadow zone' which is the large area in the centre of the earth that no P or S waves ever penetrate, and he has concluded that it is more likely that they cannot penetrate that because there is nothing there to penetrate (seismology does not work in gas).
Ok, lets examine this claim. Here is your S-wave shadow zone. These S-waves can't penetrate liquid, so we get this pattern. The same would be seen if there was nothing to penetrate I suppose. But what about the P-waves? If there were a hollow space, these would not be transmitted either surely and we would see more or less the same pattern. Instead we see this pattern. They are transmitted through. I doubt this would happen if the earth was hollow.

*There's nothing that screams bulls*** more than the phrase "scientists have discovered" followed by no citations of any kind.

 Quote by D H That's a good start. Add the Earth's magnetic field, cosmology, Occam's scalpel, ...
He explained the magnetic field is produced with Dynamo theory, which is an ionized gas (a plasma) which can be shown, with use of magnetohydrodynamic equations, that the flow of the conducting ionised materials in the interior of an object can continuously regenerate the magnetic fields of planetary and stellar bodies, similar to action observed in the sun. In terms of cosmology he could not see why gravity should be the predominant force in the universe when it is so weak. Also he said there is no reason why the burning core started burning.

 Quote by D H Finally, the gravitational attraction inside the supposed hollow earth would be zero. Supposed inhabitants inside the hollow earth would live in a near zero-g environment.
Correct, that would be because of shell theorem. I was wondering, is gravity at all related to pressure inside planets? or are they completely independant variables?

 Quote by D H THe author is completely full of it here. A hollow earth would have a very distinct seismological ring. We use seismological data to "see" to the core of the Earth. Either siesmologists have conspired to cover-up the hollow earth, or the author is lying.
He questions the data of seismology, and even proposes an alternative interpretaion of seimological data,

 Quote by D H More BS. Please read up on the incredible amounts of science that describes how our earth was formed and how we know about the inside of the Earth.
Its all derived from seismology though, is it not?

The only other method to map the underground is using HAARP technology, but thats military owned and not publicly available data.

 Quote by russ_watters You can't have a hollow gas giant (or sun, for that matter), and we've sent space probes to every planet and many, many moons. Obviously, our understanding of gravity must be correct. I love self-debunking crackpots!
He wrote that he doubts that NASA, or the RKA, would have the authority or the integrity to rubbish Newtoniam gravity when they first started to explore the solar system. Its similar to the (alleged) moon landing hoax, whether you believe it or not, NASA could tell us whatever they want and we would not know any better. Every textbook in the world would have to have been changed, the whole basis of the mass of the earth and many other ideas would have to be changed, which would make a lot of scientists look very foolish. Its quite a typical conspiracy theorist idea; where's the evidence? -they covered it up, etc.
He also suggests that this is why not many other countries have successful space programs!

 Quote by Gokul43201 This is almost entirely misinformation. The speed of seismic waves have been computed with little or no recourse to "Newtonian Gravity". The speed of these waves have been experimentally measured and the numbers agree with the theory. Furthermore, in the last couple of decades, people have used this same technique to calculate phonon velocities in multilayered semiconductor materials, which agree excellently with experimental measurements.
I agree, I found the fact that seismologists could have got the internal constitution of the earth so utterly wrong highly unlikely. Of course HE would again claim that fear of looking stupid would have prevented seismologists accepting this interpretation of the data.
I fail to see what multilayered semiconductor materials has to do with proving seismology, could you explain please.
also there are very genuine doubts about how much seismology can actually tell us about the inside of the earth.

references:
http://www.pubmedcentral.nih.gov/art...?artid=1084633
Problems of Seismology (Structural Review)
http://www.cosis.net/abstracts/EAE03...03-J-07580.pdf
British Geological Survey, West Mains Road, Edinburgh, EH9 3LA, UK

 Quote by Gokul43201 This is also completely nonsensical. Measured lava temperatures (from hundreds of volcanoes) range from about 650C to about 1200C. Temperatures in the Mantle are estimated to be about 900C. There's no reason for magma (I sure hope the author didn't call it 'lava', 'cause then he'd also be revealing his ignorance of middle school geography) to cool significantly below this temperature on its way up.
estimated being the key word here. He is not arguing there are no hot magma areas, the amount of volcanoes at plate boundries shows that clearly, and they probably get even hotter than 1200C, he is saying that they are a localised phemenon and do not necessarily reflect the temparature deep down as most people believe.

 Quote by Gokul43201 More crackpottery! For one thing, the gravitational field is zero everywhere inside the hollow - not just at the very center. Secondly, to burn hydrogen in a thermonuclear reaction (like in the sun) you need a mass of at least 8% the mass of our sun. The mass of the earth is itself about 50,000 times too small. And if you believe in a hollow earth, then it's even smaller still.
Gravity would be 0 everywhere in the hollow, which is a problem for him, but it seems strange that there is no gravity at the centre, to me anyway, as i always thought that was why the pressure was so high.
He resolved the thermonuclear reaction by using some of the latest tests in plasma cosmology, which is largely ignored by mainstream cosmologists, because it says that the Sun is a charged body that acts electrically. It also proposes that the Sun is surrounded by a plasma cell that stretches far out - many times the radius of Pluto, and that the sun may be fuelled externally by ionised plasma provided by the inaptly named 'solar wind' ( it should be called an 'ionized gas' the solar wind is actaully constituted of very fast moving ionized particles), and he quoted some questions from Lewis E. Franks, PhD, Stanford University, that i could not answer:

So one of the most basic questions that ought to arise in any discussion of the Sun is: Why does our Sun have a corona? Why is it there? It serves no purpose in a fusion-only model nor can such models explain its existence? and why is it millions of degrees hotter than the surface of the sun? This is highly unexpected for a body thats heat should raidiate uniformly from the core.

 Quote by matthyaouw Ok, lets examine this claim. Here is your S-wave shadow zone. These S-waves can't penetrate liquid, so we get this pattern. The same would be seen if there was nothing to penetrate I suppose. But what about the P-waves? If there were a hollow space, these would not be transmitted either surely and we would see more or less the same pattern. Instead we see this pattern. They are transmitted through. I doubt this would happen if the earth was hollow.
http://earthsci.org/education/teache...veloclayer.gif - its a nice diagram, but the problem is that anything near the core is pure hypothesis from seismology, the only thing you really know is where the p wave went in and where it came out. You can speculate where it travelled inside, but not prove. The waves could have been refracted around the hollow cavity due to the decrease in pressure, which would give similar results.
Its not as if we can set up accurate seismological experiments on another planet to test the accuracy of seismology, so seismology apparently works well now, and is allegedly matematically provable, but the math could very well be based on wrong assumptions about the internal constituation.

 Mentor Blog Entries: 27 Just out of curiosity, is there a reason you are giving this crackpot that much credibility (not to mention, time and effort) when compared with other reputable sources? Zz.
 Recognitions: Gold Member Science Advisor Staff Emeritus This is, as so many other crackpot theories, undebunkable. If you put everything one knows in doubt, if you put everything that is said in doubt, for a variety of reasons, then you can always come to a self-consistent, or at least undebunkable set of statements. This is in fact a philosophical truth that there is no ultimate truth that you can demonstrate. You always need to start *somewhere* to show something. So if, from the start, about everything we (think to) know is put in doubt, every attempt at debunking will consistently be put in doubt too. As such, I think that "can we show you to be wrong" not the right way to tackle these statements, because this will be an endless chase of argument-building followed by putting in doubt the premises. The creationists follow in fact the same path. The scientific question is: can that hollow-earth guy make a falsifiable prediction with his hollow-earth theory that is in contradiction with the standard view and where an experiment will show his theory right and the standard view wrong ? Or has he set up a hollow-earth-that-looks-as-if-it-were-filled theory, where all our knowledge is modified in such a way as to accomodate for a hollow-earth-that-is-not-to-be-detected-to-be-hollow-in-our-paradigm ? In that case, he might just have invented a peculiar world view which is scientifically equivalent to the standard view. In that case, his theory is a fun philosophical game, which doesn't have any advantage (or disadvantage) over the standard view. But the problem with this kind of games is that one usually has an "expanding frontier of necessary new theories" when one tracks them logically, and that the inventor of the theory has limited himself to only a small domain where his system seems not self-contradictory.
 Recognitions: Gold Member I've had a more thorough look at the guy's alternative explanations, and looking at these diagrams, things don't seem to add up. conventional model: http://www.bibliotecapleyades.net/im...ahueca/P_6.gif Hollow earth: http://www.bibliotecapleyades.net/im...ahueca/P_7.jpg A novel explanation for the wavepaths and distribution, but do the travel times match? In the hollow earth model, the waves arriving in the shadow zone take a much shorter path than those emerging close to 180 degrees from the epicentre, and they also avoid the hypothesised zone where density decreases with depth and thus should arrive much sooner than those that emerge further from the epicentre as well as being considerably stronger. Also note how in the conventional model has an area where both PKP and PKIKP waves arrive. That means two separate arrival times for waves, which again isn't accounted for in the hollow earth model. Also, isn't it possible to identify boundaries by reflection seismology as well as refraction? If we can pick up the inner core with reflected waves, that would pretty much can his whole idea.
 Mentor Blog Entries: 27 And let's not forget the results from the geophysical neutrinos that was detected by KamLAND back in 2005[1]. I'd like to see this crackpot accounts for that. Zz. [1] T. Araki et al., Nature v.436, p.499 (2005).

 Quote by ZeuZ In terms of cosmology he could not see why gravity should be the predominant force in the universe when it is so weak. Also he said there is no reason why the burning core started burning.
Yes, electromagnetism is orders of magnitude stronger than gravity, but electromagnetic forces can be attractive or repulsive and even if you can have a locally attractive or repulsive force, in a large enough sample they cancel each other.
Gravity is only attractive, so it adds continually when more and more mass is added.
Strong and weak interactions are even stronger than electromagnetism, but the vanish so fast with increasing distance that they are only active in the interior of atomic nuclei.
There is no mystery at all that gravity is the dominant force in the universe.
About the burning core, there is no mystery either. The responsible is gravity.
You must have seen the experience in high school of the rise of temperature when you compress a gas. When a cloud of gas and dust is compressed by gravity to form a star or a planet, its temperature rises. If the mass is big enough, the temperature is sufficient to start fusion reactions and you have a star. If the mass is lesser you have a planet and the temperature may be enough to fuse rocks.
Smaller bodies, like asteroids have not enough mass to be stable under the weak gravitational force, so they are subject mainly by electromagnetic interactions.

 Quote by ZapperZ And let's not forget the results from the geophysical neutrinos that was detected by KamLAND back in 2005[1]. I'd like to see this crackpot accounts for that. [1] T. Araki et al., Nature v.436, p.499 (2005).

look at this official page at the stanford site of this experiment. They are clearly not claiming to measure the internal constitution of the earth, they are detecting electron antineutrinos produced by natural radioactivity in the Earth.
They say on that page, "The Earth can be split into 5 basic regions according to the seismic data", which shows they are using seismology as if it is a proven fact, and are obviously never going to conclude anything about the structure of the earth as all they are just measuring the radiogenic power of particles coming from the earth.

they also say on that site, "The deepest borehole is ~12km, 1/500 of the Earth's radius. ", so if theres still over five thousand miles to explore, i'd say being confident that seismology is accurate to predict the exact constitution, temparature, pressure and density of the Earth is naive.

No-one has pointed out an alternative way of measuring the earths interior apart from (potentially flawed) seismology.
(they even have a picture of a hollow earth on their site, if you look at the left sphere.)

i'm glad you brought up that paper, as it clearly demonstrates matthyaouw wrong when he says

 Quote by matthyaouw I don't know where he gets his ideas of what scientists say* causes lava melt, but he's fairly far off the mark. For the major causes, firstly, yes heating is an option, but not from localised radioactive decay or faults, but from convecting material upwelling from the core-mantle boundary.
As on the Stanford site it quite clearly says that:
"The radioactive isotopes inside the Earth generate heat. In particular, decays of the daughter nuclei in the decay chains of 238U and 232Th, and 40K generate most of the radiogenic heat produced. According to some of the mantle convection models, these two numbers, 44TW (or 31TW) for the total heat dissipation rate from the Earth, and 19TW for radiogenic heat production rate should be similar.
As these radioactive isotopes beta-decay, they produce antineutrinos. So, measuring these antineutrinos may serve as a crosscheck of the radiogenic heat production-rate"

so actually Jan is quite near the mark when he says heat is produced from radioactive isotopes in the earths crust.

 Quote by Gokul43201 This is also completely nonsensical. Measured lava temperatures (from hundreds of volcanoes) range from about 650C to about 1200C. Temperatures in the Mantle are estimated to be about 900C. There's no reason for magma to cool significantly below this temperature on its way up.
Estimated, yes, proved, no. You have also assumed that seismology is accurate in measuring the temparature of the earths interior in the first place, as seismology is the only method of knowing what is under our feet more than 20 miles down.

 Quote by CEL Strong and weak interactions are even stronger than electromagnetism, but the vanish so fast with increasing distance that they are only active in the interior of atomic nuclei. There is no mystery at all that gravity is the dominant force in the universe... Smaller bodies, like asteroids have not enough mass to be stable under the weak gravitational force, so they are subject mainly by electromagnetic interactions.
I agree about asteroids being affercted more by electromagnetic interactions. Infact some cosmologists believe that the tails on comets are electrical discharges as the comet travels rapidly through local stars electric field (or "ion wind" ). if you look at these pictures of comets its quite obviosly electrical in nature. The details of this observed phenomenon are here.

I know that the srong nuclear force and the weak force are too strong to work on a scale as large as planets as they only effect the subatomic level, but he didn't mention the weak or strong force. He specifically mentioned magnetism, charge and electricity. We all know what happens when you apply an electric field to, for example, an electron, it will experience a force in a certain direction, ( F = Ee ) or similarly with a magnet. If you are using a magnet to pick something up, the WHOLE of the earth is pulling down on it, yet you are able to overcome this with something in your hand. I think it is actually quite logical to assume that magnetism and charge play a part in planetary formation since they are so much stronger and dominant in the universe we observe.

 Quote by CEL About the burning core, there is no mystery either. The responsible is gravity. You must have seen the experience in high school of the rise of temperature when you compress a gas. When a cloud of gas and dust is compressed by gravity to form a star or a planet, its temperature rises. If the mass is big enough, the temperature is sufficient to start fusion reactions and you have a star. If the mass is lesser you have a planet and the temperature may be enough to fuse rocks.
Thats what i want to know, because i'm not sure it is. Newtons shell theorem says gravity is 0 at the centre, and infact at the centre you would be being pulled out in every direction, so i cant imagine there would be much pressure there since all the forces are acting outwards on you.

is there a relationship between pressure and gravity inside planets? or are they completely independant variables? it seems odd they are independant as the alleged reason the pressure is so high at the centre is due to gravity, but gravity = 0 at the centre.