Lagrange L1 - Global Cooling - Solar Power
 

I was thinking again that the easiest / cheapest way to cool the planet is probably just to block some amount of the sunlight. freebeard has discussed the idea of a lens at lagrange L1 in space between the sun and earth to shift the light a couple degrees so that it misses the earth.

Lagrange points are the neutral gravity points between 2 large objects, like planets, moons, and the sun. An object placed at any of these 5 points tends to maintain their relative distance between the 2 large objects because the gravity pulling on one side is cancelled by the gravity pulling on the other side.

L1 is the point between the 2 objects, in this case the sun and earth. Perhaps solar panels (films) could be deployed at this point about a million miles away at L1, generate electricity 24/7, and beam it to earth while blocking some of the sunlight that warms the planet.

Solar pressure would tend to push the solar array away, but perhaps that could be compensated by moving a little closer to the sun at a new compensated L1 point. Another idea is ion engines to compensate.

Anyhow, I found a fun website that discusses some of these ideas in more depth, and suggests it would be possible to shoot the payloads at escape velocity using rail guns.

https://www.pnas.org/content/103/46/17184

I haven't read all the way through yet, but I wonder how many Gs of acceleration over what distance would be required to achieve the necessary 28,600 MPH?

We dot need to cool the planet. Unless your real agenda is to starve millions of poor people in 3rd world countries to death.

Well of course not. But if in the future you did need to, that seems to be the way to go,

I don't remember the part about shifting the light a few degrees. That doesn't mean I disbelieve you. :)

I'd suggest a better option would be at Mars' L1 with the solar energy powering a Magnetron to throw a 'magnetosphere' up like a bug deflector.

Give up on earth?

The deflection was proposed (somewhere) because it suffers less solar sail effect than absorption or reflection.

I propose absorbing it to harness the electricity, but accounting for the solar sail effect by creating a modified L1, or ion engine compensation (combination of both).

I wonder what would happen if the earth received 1% less sunlight. Can't be good for most plants I'd think. Lower crop yields?

Light is not a problem. Low humidity, weather, pests and lack of nutrients are.
Greenhouses produce way more than open fields, mainly because they allow farmers to control conditions. The glass inevitably takes away some of the light, but that doesn't matter - even at 52 degrees north.

In order to block 1% of the light reaching the Earth the screen needs to be bigger than Texas. That may be prohibitive.
It is easier to reflect the light on Earth itself. Paint everything white.

The future is cold.

and then warm again, cold again, warm again... eventually culminating in entirely too warm, followed by increasing coldness for all eternity.

I began disliking the word cold once I understood there is no such thing, just like darkness. I'd be looked at funny if I said "there's insufficient heat" instead of just saying "it's cold".

Off topic. Sosueme.

Fossil free steel. Another giant step towards net carbon zero?

This process substitutes hydrogen for coke and operates at lower temperatures. It produces sponge iron which can be treated like recyclable steel.

They pitch it a a solution for carbon dioxide reduction (both energy saved and gases reduced) but it occurs to me that this will be important off-planet. Mars needs stainless steel.

I take all threads OT, so I expect no less from others. OT is the natural progression of any discussion.

Cool to think about, because I had never considered the preciousness of O2 on other planets and the need to manufacture without it.