Re: OT: Dyson's Disaster

> Date:         Wed, 5 Dec 2001 23:05:38 -0800
> From: Anton Sherwood <bronto@...>
>
> Andreas Johansson wrote:
> > Another problem: While the sphere won't be attracting anything inside it,
> > any bodies within it will attract eachother, wherefore air will be
> > dropping into the sun. Spinning the sphere won't help, since the air at
> > the poles would still fall into the sun, creating a low pressure that
> > sucks in more air und so weiter.
>
> The poles would then be effectively at high altitude.
> Does the low pressure on mountaintops suck in air from below?
Good point --- the mid latitudes will effectively be mountainsides
climbing into airless space. As noted already: As you move away from
the equator of sphere, the resultant force (sum of solar gravity and
centrifugal force) will be at an angle to the surface; at some point
it will be parallel to it, and everything will slide back towards the
equator.

So yes, if you fill the whole sphere with air, most of it will fall
into the sun, but there'll be a broad equatorial belt that can retain
an atmosphere. And the solar wind won't be blowing it away, it'll add
to it instead.

Lars Mathiesen (U of Copenhagen CS Dep) <thorinn@...> (Humour NOT marked)