Regarding Hollow Bodies

Charles:
Last November Charles said this about hollow bodies on the TB forum:

http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=7315&start=60#p72763
As concerns "hollow planet" theories, I'm not sure that I fully understand them. Lamprecht [in the article that Brant referenced above - ed.] is correct that centrifugal force increases with distance from the center, assuming solid body rotation, meaning that the tangential velocity is greater. He's also correct that gravity increases with distance from the center, out to the edge of the planet. And he's right that this might initially form a ring-like structure, or a planet with "open poles" as he calls it. But how do the poles get closed into a sphere with a hollow center?

http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=7315&start=90#p73110
Helioseismology actually doesn't tell us much about the core, except that it is definitely there, and it definitely has a different density, because it produces a distinct shadow on the opposite side of the Sun. But p-waves don't pass through the core, so we don't know anything about the density gradient (if any). This, in fact, is what leaves the topic open to the speculation that it's hollow, while my take is that it's frozen rock solid, and p-waves bounce off of its rigidity. I agree that the density is probably quite consistent, and I agree that the reason would be electrostatic repulsion between ions. But we can't say that the seismic data support these assertions.

Brant:
I know you've considered LeSage's and Fatio's theory that gravity is a surface phenomenon. Is that a necessary part of your theory? If so, do you have evidence that gravity only affects surfaces? Mathis says the gravitational equation is actually a unified field equation, with gravity affecting only the volume of a body and EM affecting the density. So Mathis seems to have a good theory to explain it. Do you or the others have a good theory to explain why gravity only affects surfaces? Charles seems to have good evidence in his model that helioseismology shows that the density goes up with depth. However, I showed Charles a Wikipedia article last year that shows the density (or gravity?) at the Earth's center is zero and rises steadily to about 90% halfway to the surface, then rises more gradually and a bit unsteadily till it reaches the Earth's surface. He seemed to find the article believable at that time, but I don't think he said why he didn't think bodies are hollow.