[VadeRetro]

However, for satellites, the mass of the Earth is so much greater than the mass of the satellite, the effective center of mass is the center of the Earth.

Now if you want to get really picky ...

The earth has a non-trivial moon, which makes it wobble slightly in its solar orbit. Thus, the real center of mass of the earth-moon system is a bit off from the geographical center of the earth. Since the satellite also feels the tug of the moon, it is basically orbiting the earth-moon center of gravity.

[skinkinthegrass]

Now if you want to get really picky...

The difference is, What?...In the total Volume of the cosmos?...I know, a miss, is a miss...no flames, Please :/...as a skink, I do like it warm. :))

[RadioAstronomer]

The earth has a non-trivial moon, which makes it wobble slightly in its solar orbit. Thus, the real center of mass of the earth-moon system is a bit off from the geographical center of the earth. Since the satellite also feels the tug of the moon, it is basically orbiting the earth-moon center of gravity.

:-)

Lets get even pickier. Add the effects of both Jupiter and the Sun. :-)

[edwin hubble]

"The earth has a non-trivial moon, which makes it wobble slightly in its solar orbit. Thus, the real center of mass of the earth-moon system is a bit off from the geographical center of the earth. Since the satellite also feels the tug of the moon, it is basically orbiting the earth-moon center of gravity. "

Yes, The center of mass of the Earth-moon system lies about halfway between the Earth's center and its surface. This 'wobble' of the Earth is responsible for the second tide each day - on the side opposite the moon.