Re: ZetaTalk and Spaceguard UK (D8)

Bill Nelson wrote:
> In sci.astro Nancy Lieder <[email protected]> wrote:
>> This produces some interesting results, where the Moon
>> could theoretically orbit at the same distance as Satellites,
>> at the same velocity (see next post).
>
> Unfortunately, you have shown that you do not understand
> orbital dynamics  ... Nor have you provided any mathematical
> support for what is really a very simple physical system.

Bill Nelson, meet Magnus Nyborg.  I was using his math.

This law takes into consideration ONLY the mass of the primary.  So my
statement above is correct, as confirmed by (one of the) Greg Neills
personas and David Tholen. (Greg is still arguing with himself, having
been momentarily discombobulated by cracks in Newton appearing before
him. Where is that contact cement!)

Magnus Nyborg wrote:
> Orbital speed for ideal circular motion of a low-mass object
> circling a high-mass object M (which refers to it's mass) is
> determined by the formula
>
>    v = sqrt( G*M / r )
>
> Ground orbit (if possible) -
>    v = sqrt( 6.67E-11 * 5.976E24 / 6.378E6 ) = 7905 m/s
> Satellite orbit -
>    v = sqrt( 6.67E-11 * 5.976E24 / 6.478E6 ) = 7844 m/s
> Moon orbit -
>    v = sqrt( 6.67E-11 * 5.976E24 / 3.844E8 ) = 1018 m/s
>