Re: Building a decent vacuum at the gravitational center of the Earth.

On Jun 27, 11:28 pm, John C. Polasek <jpola...@xxxxxxxxxx> wrote:
On Thu, 26 Jun 2008 09:49:16 -0700, Uncle Al <Uncle...@xxxxxxxxxxxxx>
wrote:

Jeff?Relf wrote:

It'd be unimaginably expensive to  build / maintain
a decent vacuum at the gravitational center of the Earth;
but, if you did, a sphere of lead inside the vaccum
would be forced  Down  to the center of it.

Hey fucking stooopid - there is no net gravitation at the Earth's
center of gravity.  That is how Satan and his demons fly.  That is why
the sun's core diffuses photons rather than convects heat with mass.
There is no "up".

Sure there is. The gravity is proportional to radius, like a linear
spring. Consequently,  the lead ball would oscillate up and down. In
fact the period of oscillation would be 84.4 minutes, irrespective of
the mass of the ball.
This is the same period known as Schuler tuning in inertial guidance.
        Period = 2pi*sqrt(Rw/g) = 84.4 minutes.
        F = mg0*r/Rw
        K = F/r = m*g0/Rw
        w = sqrt(K/m = g0/Rw), and so on
Odd, what?
John Polasek

The proof of Newton's Shell Theorem is an elementary exercise in
analytical geometry.
http://encyclopedia.thefreedictionary.com/Newton%27s+sphere+theorem
A clever 17-year old could prove it. You will notice it is called a
"theorem" and not a "hypothesis." It has been proven with
mathematical rigor.

Within the hollow of the sphere there is no mass to provide a central
force, while outside the hollow the mass distribution is such that the
gravitation force applied on a body within the hollow by one mass is
cancelled by an opposite force arising from the mass directly across
the hollow.

"Schuler tuning" applies to a different problem - that of a "small
body falling down an airless tunnel running from the North Pole to the
South Pole through the center of the earth"
http://en.wikipedia.org/wiki/Schuler_tuning

Tom Davidson
Richmond, VA
.

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