Underground Rivers - University of New Mexico

Chapter 14 -- Hollow Earth Geophysics
On the bottom if the diagram to the right we have the world as
explained by Newton.
A segment of a solid rotating earth with a waterfall on its
surface.
Gravitational force causing the water to fall downward.
Gravitational force doesn't depend on the earth's rotation.
On the top we have Teed's explanation.
A segment of a spinning shell with an upside-down waterfall
on its inner surface, "upside-down" on the page, that is, not
to an inner-world citizen.
Centrifugal force pushing the waterfall outward.
According to Teed, the waterfall we think to be directed by gravity is in fact responding to outward
centrifugal force. It makes conceptual sense, perhaps, at least until we look at the math.
To begin, let's consider a non-rotating solid globe, Case 1 below, in which the only force
operating is that of gravity,
Gravitational force = m g
DRAFT 1122//66//22001122
Centrifugal
Force
Gravitational
Force
where m is an object's mass, and
g is the gravitational constant, 9.81 meters/second 2 at the earth's surface.
Earth
The radial lines represent gravitational pull toward the center of the globe. For a given object, the
g's magnitude is the same everywhere on the surface.
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Shell
Rotation
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