Re: A newcomer here

In article <ddfr-C4F6D6.15423011092005@xxxxxxxxxxxxxxxxxxxxx>,
ddfr@xxxxxxxxxxxxxxxxxxxxxxxxx says...
> In article <gcb9i1tbm7a6a6msoadg4v2mn0ka5kkd5g@xxxxxxx>,
> John F. Eldredge <john@xxxxxxxxxxxxxx> wrote:
>
> > >Making a hollow beach-ball planet strong enough to avoid self-collapse
> > >and to avoid breaking apart with the tidal forces is, of course, an
> > >interesting exercise.
> >
> > If the planet has greater-than-Earth mass, it will have
> > greater-than-Earth gravity. Hollowing out the interior of a planet
> > (while presumably using some sort of handwavium force field to keep it
> > from collapsing inward under its own weight) will result in less
> > gravity, not greater gravity.
>
> The idea is to keep gravity at the surface down to about 1G, while
> having a much larger mass than earth's--and hence a much stronger
> gravitational field out where the orbiting sun is. Since gravity is an
> inverse square force and a spherical shell has the same field, seen from
> the outside, as a point mass of the same mass located at its center,
> increasing the radius of the shell lets you increase its mass without
> increasing surface gravity.

How about a dense set of orbiting rings? It would also give a 'flat
earth' appearance that will be ideal for the original proposer...

- Gerry Quinn
.

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