Timothy Murphy wrote:
Fleetie wrote:

To a pedant, that is correct. The earth orbits the centre of mass of
the whole solar system (to a first approximation). That might not
always lie within the Sun.
It is always within the Sun. As one would intuitively expect.


http://en.wikipedia.org/wiki/Barycen...nd_astronom y

Does that say the centre of mass of the solar system lies within the sun?
As I read it, it says the centre of mass of the sun and jupiter
is a little outside the sun (742,000 km from the centre of the sun,
which has radius 696,000 km).
This seems to imply that the centre of mass of the solar system
is usually, if not always, just outside the sun.

Ah, but where does the sun 'end'

The solar 'atmosphere' extends a long way out ;-)