Man, this thread was like, ancient-history-esque.... but okay.

The center of gravity of a concave object **may not** be inside the object's surface. For a bowl with enough slant for a FE to slide toward the center it may be above the surface.

Right, but, on the other hand, it might indeed be below the surface. I kinda imagined that the mother disc was supposed to be *huge*, like, much much thicker and much much wider than the Earth. If it were a hundred times thicker, say, then the "bowl" could be fairly shallow, and the center of gravity would still be below the surface of the bowl.

This could potentially make theta very noticible because we're not attracted to a point way under the earth.

Right, we'd be attracted to a point... up in the air. That would be wierd.

It also makes the math of calculating gravity very tricky. Instead of simply using the total mass of the disc and distance to geometric center, you'd have to do a volume intergral of the bowl.

I wave my private parts at your volume integral. The bowl is point-symmetric about its central axis. Also, if the bowl is, say, a paraboloidal or spherical indentation in a cylinder (i.e., parabolic or circular, after we subtract one dimension due to symmetry) it reduces to a simple matter of subtracting a small chunk of nicely-shaped area from a rectangular area, and rotating around an axis. Child's play.

Anyway, if, again, the bowl is very shallow as compared to the thickness of the disc, we can actually ignore it, an imagine the disc is just a cylinder.

For some reason, I like this hypothesis better than the accelerating upward model. Although, the centripetal model is intriguing too. I guess it is because both of these assume a finite universe instead of an infinite one with nothing else in it.

One problem with this theory arises if you actually think that naked-eye and telescoping observations of satellites are not illusions or something. Some satellites follow lines of longitude; how would they get through the big disc?

Anyway, I think I like the mother pillar theory better than the mother disc theory. You need the disc to be really thick anyway, so that the center of gravity is as far down away from the Earth as possible. Having a very wide disc doesn't really help, except insofaras it adds mass.

The problem with a more distant centre of gravity is that we can actually measure the distance to the centre of gravity using the inverse-square relation for gravity. From that, we can calculate the mass of the pillar or disc required.

The problem with a closer centre of gravity is that the angle between gravity "rays" becomes greater, given different places of measurement on the Earth.

Lastly, the problem with the centrifugal acceleration model, while appealing, is the same as with the linear acceleration model: why does it appear that the stars have this simple circular motion through the sky? Don't forget that east and west would be *tangent* to the Earth's motion in the centrifugal acceleration model... the sky would look totally wierd. Essentially you have to assume that the sky is somehow fixed to the Earth, and moves around with it. But we can use parallax to determine the distance at least to nearby stars, so it's a *big* dome.

Anyway, keep working on those alternate theories :)

-Erasmus