Lets talks about how I see the exact center of the Earth and it motion.
Most excellent questions from Curt Youngs.
Does your theory explain why the plumb bob normally points to the center of the earth? (some times it is off a little bit, regardless of whose it is.) There seems to be a relation between gravity and inertia. Nobody has explained that very well, except in their own mind, well, maybe some that are not well known. Do you have some ideas about this?
Yes, I have thought on this. I think the plumb bob is pointing to where the center of the Earth was. I just ran out and got my plumb bob. I tied the bob in our moving car.
My wife drove us to McDonald's to get milkshakes(helps the tongue after a seizure). When the car was accelerating ~consistently it would point to where the center of the Earth was plus the car's acceleration as theta. The only severe changes occurred during gear shifts and bumps.
Does your theory explain why the plumb bob normally points to the center of the earth?I think this effect is caused by the spin of the earth.
'some times it is off a little bit, regardless of whose it is.'I think this relationship is the changing velocity of the Earth around the Sun. The longer the string the more accurate the measure. The change in theta is the velocity. The reason for the sometimes is the position in its orbit. Angular Velocity of the Earth is different at each clock point around the sun.
There even will be a slight error because of the Sun's velocity around the galaxy.
The Earth is spinning on its axis. The Earth is in Orbit around the Sun. The Sun is in orbit around the galaxy.
So. Lets change the plumb bob to a pulse laser. The laser is pointing to the center of the earth. There is this amazing vacuum tube that has been inserted to the center of the earth from my house. It won't crush, bend or melt. The tube is 1 meter in diameter. At the top of the tube the pulse laser is placed exactly in the center of the tube. There is a exact detector at the other end. The detector shows us the exact amount the laser is off the center of the earth.
When the laser pulses it travels 6,375 km and hits the detector. It does not hit the center of the detector. This error is caused by the motion of the earth around the sun. Where the earth was. It may take less than a sec to get to the center of the earth but the earth has moved around the sun in that time. The motion of the spin of the earth is removed by the vacuum tube.
This is another major issue I have with the n-body problem. Euler transformation kind of solves this issue but it doesn't. We always have an issue with where things were vs where they are now. Its a clock problem. Gravity, not well thought out.
I wrote this first on GSJ
Ok. Lets forget about the laser. I just think it was a more stable example of the motion of the earth. The plumb bob is affected by gear changes, bumps and atmosphere. Just trying to remove a few variables.
Lets build a 1000m stand holding the plumb bob. The stand is held in a vacuum tube so the atmosphere is not relevant here. The spin of the Earth stabilized the bob to always point down. Let the bob hang there for several years. The bob would only show the error Curt is referring to.
If we were to do this experiment on Eros(an irregular shape strange spin) the bob would take time to stabilize. By adding the bob it would move the barycenter of Eros. The pattern drawn by the bob would be irregular but different than the original pattern when the bob was first added.
Its the spin of the earth that causes the stability.
The error is caused by the earth's position about the sun. The angular velocity of the earth changes for every position. This change is the error.
(Addendum:9/25/08) Curt Youngs - Mascons also affect the plumb bobs on Earth.