[ExI] The Great Silence again

[Eugen Leitl]

On Mon, May 02, 2011 at 12:50:09PM +0200, Stefano Vaj wrote:
> On 30 April 2011 21:06, Keith Henson <hkeithhenson at gmail.com> wrote:
> > For a non rotating Dyson sphere that's thin enough the light pressure
> > would balance the gravity from the sun.  The light pressure at the
> > distance of the earth's orbit is around 9.3 N per square km.
> 
> Now that you make me think of it, in a non-rotating Dyson sphere
> object on the internal surface would be bound to fall towards the sun,
> right? The gravity of even a relatively thick surface would hardly
> compensate...

There's no point in a solid Dyson sphere, as photonic pressure
makes for impractically thin shells.

You can consider a circumsolar cloud of nodes in active orbits
with photonic sails. Inasmuch the cloud can use active sail tilting
to produce anisotropic radiation emission which is useful for
propulsion is not too obvious. You can spend 1:1 duty cycle climbing
orbits up and down, so net effect is zero. You can switch them to
transparency, like window blinds.