"Chuck Gould" wrote in message
ups.com...
On Feb 22, 10:20?am, "Calif Bill" wrote:
"Chuck Gould" wrote in message

ups.com...

In the interest of sustaining this worthwhile feature in the NG, I
offer:

barycenter (n): A theoretical point 810 miles below the surface of
planet Earth. This point is the rotational center of the Earth and
Moon. The gravitational attraction between Earth and Moon affect the
oceans and their tides; centrifugal forces result from their
revolutions around the barycenter.

( above definition by Lenfestey/Lenfestey)

The barycenter is a definite consideration when examining the physics
of tides, particularly the standing wave on the side of Earth opposite
the position of the moon.

It is defined as the Center of Mass of a System, not the center of
rotation..

In a sense it is also a center of rotation, of the combined masses.

Here's a link to a site that offers a free "gravity simulator" that
demonstrates
celestial bodies rotating around a common barycenter. I wasn't sure I
wanted to download the required program to view it:

http://www.orbitsimulator.com/gravit...arycenter.html


More like the center of rotation in regards to an outside object. A NEO
Near Earth Object ie. asteroid would use the center of mass in it's path for
a center of gravity. If it was the center of rotation of the earth and
moon, we would be traveling like a corkscrew in our path around the moon. A
fairly large corkscrew. Since the earth is about 8000 miles diameter, the
center of rotation as you describe it being 810 miles from the surface, you
would have an about 3200 mile diameter corkscrew.