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Re: Bulges



Have I got this right?
Don Simanek doesn't think the fact that the earth & moon orbit about their
center of mass needs to be included in an explaination of tidal bulges.
Mark Sylvester explains that without the orbiting there would be only one
bulge.
Don and Lee disagree with Mark?
Certainly we all agree that an elastic body, or a fluid body (a more realistic
model for the earth in this case) placed in a gravitational gradient will
deform to an oblate spheroid, don't we?
I think the difference is what one uses as a reference for measuring a bulge.
Mark wants to nail the earth and moon in space.
If we nail up a spherical earth and then bring in the moon, certainly all the
distortion of the earth is the result of earth material being pulled toward
the moon. Mark calls this one bulge. No part of the earth is repelled by the
moon! I think his reference is the nails holding the earth and moon "fixed".
Do you disagree with his conclusion?
Lee wants to throw water on the nailed down earth and moon. I claim, and I
think Mark would agree, that if you throw water on the earth all the water will
run over to the moon side of the earth, one bulge. To get water on the other
side of the earth one needs to spin the earth moon system about the center of
the mass. The obiting of the center of mass is not needed to get oblate shapes
it is needed to get water on both sides of the earth!
The Kowalski experiment is great. However, note that his earth is falling, it
is not nailed down. As Mark said, this is what is needed to get water on both
sides of the earth. If Kowalski nails down the earth & moon he gets one bulge.