Re: What is True About the World (was: new to list)

From: Louis Newstrom (nnewstro@bellsouth.net)
Date: Fri Aug 31 2001 - 14:17:28 MDT


----- Original Message -----
From: "Mike Lorrey" <mlorrey@datamann.com>
To: <extropians@extropy.org>
Sent: Friday, August 31, 2001 1:24 PM
Subject: Re: What is True About the World (was: new to list)

> Lee Corbin wrote:
> >
> > > A properly unbiased frame of reference would consider the center of
> > > orbital rotation, the point both the sun and its planet rotate about.
Lo
> > > and behold, because the sun is so much more massive than any other
> > > planet, the center of rotation is only a few meters from the center of
> > > the sun.
> >
> > Not a few meters: more like about 500,000. (Mass of sun: 2x10^30kg,
> > mass of Jupiter: 2x10^27, a ratio of 1000 to 1. But the distance
> > between the sun and Jupiter, 5.2 AU, is around 500,000,000 miles.)
> > So the center of revolution isn't really inside the sun (diameter
> > 867,000 miles), but lies outside it many thousands of miles.
>
> By my calculation, 500,000 meters is 500 km, which is still inside the
> sun.

I think he meant 500,000 miles, not meters.

My calculations are based on Sun mass = 1.989E+30 kg and Jupiter mass =
1.90E+27 kg, a ratio of 1047 to 1.
Since Jupiter is 778,330,000 km from the Sun, the center of mass would be
743,503 km from the center of the Sun.
The Sun has a radius of 695,000 km, so the center of mass would be slightly
outside of the sun. (By a margin of about 7%).

P.S. 695,000 km is about 462,000 miles.



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