Space Ring Could Shade Earth and Stop Global Warming

A wild idea to combat global warming suggests creating an artificial ring of small particles or spacecrafts around Earth to shade the tropics and moderate climate extremes.

There would be side effects, proponents admit. An effective sunlight-scattering particle ring would illuminate our night sky as much as the full Moon, for example.

And the price tag would knock the socks off even a big-budget agency like NASA: $6 trillion to $200 trillion for the particle approach. Deploying tiny spacecraft would come at a relative bargain: a mere $500 billion tops.
Live Science