[extropy-chat] Re: SPACE: new planet?

[Technotranscendence]

On Saturday, February 21, 2004 8:23 AM Mike Lorrey mlorrey at yahoo.com
wrote:
>>> The distortion of Earth's orbit does not exceed the
>>> boundaries even of the earth's core.

Wrong!  The Earth's core (inner and outer) is about 2200 km wide.

>>> The center of angular momentum is only a few
>>> meters
>>> from the center of the earth, or so I've heard.
>>
>> I thought it was almost 4,900km from the center
>> of the earth.  Or is
>> that
>> just the center of gravity?
>
> Perhaps we have a problem with terms here. What would you call the
> point which both earth and the moon orbit around?

The term is barycenter.  It's located about 4641 km from the center of
the Earth -- in the direction of the Moon obviously:) -- and this puts
it closer to the Earth's surface than to the Earth's center and outside
the core.  (Earth's radius is about 6400 km.)

Anyhow, the barycenter is the center of mass for the Earth-Moon system.
Both Earth and Moon orbit it -- in a manner of speaking.:)

Cheers!

Dan
http://uweb.superlink.net/neptune/MyWorks.html