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Re: ZetaTalk and Spaceguard UK (D8)


Greg Neill wrote:
>>>> The GIVENS:
>>>>      Constant as m * p^2/d^3 is constant for all orbits.
>>>>       where  m = mass of primary
>>>>              d = distance
>>>>              p = period
>>>> This produces some interesting results, where the Moon
>>>> could theoretically orbit at the same distance as Satellites,
>>>> at the same velocity.
>
>>> It is true that the velocity for circular orbit of a relatively
>>> small mass around a large mass depends only upon the
>>> distance from the large mass.
>
>> Newton's centrifugal force law only takes into account the
>> mass of the Primary.  You are saying, below, what I've been
>> asserting - that this does not fit with the Inverse Square law.
>
> The centrifugal force does not depend at all upon the
> mass of the primary ... Please show where I (or my evil twin)
> stated that the centrifugal force depends upon the mass of the
> primary in any other way than as the result of the secondary's
> acceleration due to gravity.

Sure.  Greg Neill meet Greg Neill, and have both of you met Magnus
Nyborg?

Greg Neill wrote:
> Please show me where they are not equal if they are written
> as equal:
>        G*M1*M2/r^2 = M2*v^2/r
> The equation above says that they're equal.
> We know that they are equal by observation
>      (circular orbit ==> inward force = outward force)

And this reduces to the Velocity equation, by factoring OUT the mass of
the secondary, M2, so that ONLY the mass of the primary is a concern.

 Magnus Nyborg wrote:
>    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

Greg Neill, meet Greg Neill, etc.

Greg Neill wrote:
> The formula stated, namely
>      v = sqrt(G*M/r)
> is valid within the stated conditions.