"Martha Adams" wrote:
:
:A 100,000 square mile sunshade works out to about 357 miles diameter.
:Compared to 8000 miles diameter for Terra, it doesn't look like much. I
:suppose it could be orbited in the subsolar trojan -- which I don't
:think is a very good trojan, so it would need frequent adjustment.
:
:What would this accomplish and from an engineering point of view, is it
:doable?
:

The idea is presumably to reduce insolation of the Earth by blocking
part of the incoming sunlight, thereby reducing temperatures (it makes
the greenhouse effect a feature keeping us warm in the face of the
shade rather than a bug frying us all). I'm a bit curious what the
reduced energy levels do to plant life, though.

It's probably possible from an engineering standpoint, but it's a huge
undertaking. Imagine the thing as a huge solar sail maintaining
position between the Earth and the Sun. It's not really in an 'orbit'
at all, but is rather under constant acceleration, not orbiting the
Sun quickly enough to maintain an orbit and using solar sail 'thrust'
to keep from falling inward.

:
:My own thinking is, how about direct application of solar power and
:local water to reconstitute our excess carbon dioxide back into
:hydrocarbons? Which could then be re-used as fuel again, or serve for
:structural applications?
:

I'm not sure the sunlight and the water exist in anything like the
same places or that there is sufficient clean water available to make
this work.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw