Reply To: Global warming solutions? – geo-engineering? PV cells?


Now, on Science website, an idea for reducing sun reaching the earth by having screen of tiny spacecraft – each a transparent disc.

… one astronomer has come up with a radical plan to cool Earth: launch trillions of feather-light discs into space, where they would form a vast cloud that would block the sun’s rays.

Instead, University of Arizona Steward Observatory optics expert Roger Angel proposes using screens just 0.6 meters across, weighing about a gram each. These discs would be manufactured on Earth using very thin, transparent material that doesn’t reflect the sun, but instead refracts it, so as to avoid having the sun’s radiation push them out of orbit. The discs would also have three 0.1-meter-long protruding electronic “ears” with a solar power source so they could adjust their position, making them essentially tiny spacecraft.

so far, so good, perhaps, but then:

About 16 trillion flyers would have to be deployed, which could be done with 20 launchers that would each send up a stack every 5 minutes for 10 years.

yeah, right – like governments are about to get their acts together enough to do this. (And what if get too much cooling, or other problems, anyway?)
A Sunshade for Planet Earth