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New paper offers a wild twist on a well-worn geoengineering concept.
Proponents of a “moonshot” idea to deal with global heating have been handed a new, very literal, interpretation by researchers who have proposed firing plumes of moon dust from a gun into space in order to deflect the sun’s rays away from Earth.
The seemingly outlandish concept, outlined in a new research paper, would involve creating a “solar shield” in space by mining the moon of millions of tons of its dust and then “ballistically eject[ing]” it to a point in space about 1 million miles from Earth, where the floating grains would partially block incoming sunlight.
“A really exciting part of our study was the realization that the natural lunar dust grains are just the right size and composition for efficiently scattering sunlight away from Earth,” said Ben Bromley, a theoretical astrophysicist at the University of Utah, who led the research, published in Plos Climate. “Since it takes much less energy to launch these grains from the moon’s surface, as compared with an Earth launch, the ‘moonshot’ idea really stood out for us.”
Bromley and two other researchers considered a variety of properties, including coal and sea salt, that could dim the sun by as much as 2 percent if fired into space. The team eventually settled on the dust found on the moon, although millions of tons would have to be mined, sifted and loaded into a ballistic device, such as an electromagnetic rail gun, and fired into space each year into order to maintain this solar shield.
Getting this mining and projective equipment to the moon would be a “significant project,” Bromley conceded, and might also require the positioning of a new space station in an area called the L1 Lagrange point, found between Earth and the sun, in order to “redirect packets of dust onto orbits that could provide shade for as long as possible.”
Such an approach would act as a “fine-tuned dimmer switch, leaving our planet untouched,” Bromley said, an advantage over other solar geoengineering proposals that have raised concerns about the environmental impact of spraying reflective particles within the Earth’s atmosphere.