shade the poles to slow or stop global warming with SPS

"Ian Stirling" wrote in message
...

Unless it's a rather extended object.
7000Km dia lens, with a shield round it to block out light going round
the sides, and focusing some 10000Km behind the lens, at which point you
get a 100Km image of the sun.
There you put an array of switchable blinds/filters.
Add another lens behind this to project that image onto earth, and you're
done.

What keeps the "other lens behind this" in position? By this point we're
many thousands of kilometers Earthward of the L-1 point.

--


Regards,
Mike Combs
----------------------------------------------------------------------
Member of the National Non-sequitur Society. We may not make
much sense, but we do like pizza.

"Mike Combs" wrote:

"Ian Stirling" wrote in message
...

Unless it's a rather extended object.
7000Km dia lens, with a shield round it to block out light going round
the sides, and focusing some 10000Km behind the lens, at which point you
get a 100Km image of the sun.
There you put an array of switchable blinds/filters.
Add another lens behind this to project that image onto earth, and you're
done.

What keeps the "other lens behind this" in position? By this point we're
many thousands of kilometers Earthward of the L-1 point.

Solar sails. You've certainly got plenty of light to play with in this
scenario.

Mike Combs wrote:
"Ian Stirling" wrote in message
...

Unless it's a rather extended object.
7000Km dia lens, with a shield round it to block out light going round
the sides, and focusing some 10000Km behind the lens, at which point you
get a 100Km image of the sun.
There you put an array of switchable blinds/filters.
Add another lens behind this to project that image onto earth, and you're
done.

What keeps the "other lens behind this" in position? By this point we're
many thousands of kilometers Earthward of the L-1 point.

I don't really think that's the biggest engineering challenge...
Worst case, rather a lot of rope, total gravitational accelleration
should be quite modest across the structure.

"Alan Anderson" wrote in message
...

Solar sails. You've certainly got plenty of light to play with in this
scenario.

That would be helpful if the problem was some force pushing the lens towards
the sun away from the Earth. Our problem is the opposite one.

--


Regards,
Mike Combs
----------------------------------------------------------------------
Member of the National Non-sequitur Society. We may not make
much sense, but we do like pizza.

"Ian Stirling" wrote in message
...
Mike Combs wrote:

What keeps the "other lens behind this" in position? By this point
we're
many thousands of kilometers Earthward of the L-1 point.

I don't really think that's the biggest engineering challenge...
Worst case, rather a lot of rope, total gravitational accelleration
should be quite modest across the structure.

OK, if I get you right we're talking about a very long structure with one
end with a giant lens (or shade) considerably closer to the Earth, but
nonetheless which has its center of gravity at the L-1 point. I'd wondered
about such a possibility, but my mind rebelled at the lengths required. At
the very least, it complicates the design a good deal over simple sunshades
at L-1, but still might wind up being more efficient, I suppose.

Maybe we could use an asteroid as a counterweight to minimize the required
length sunward of L-1.

--


Regards,
Mike Combs
----------------------------------------------------------------------
Member of the National Non-sequitur Society. We may not make
much sense, but we do like pizza.