One idea for fighting global warming is to increase the amount of aerosols in the atmosphere, scattering incoming solar energy away from Earth’s surface. But scientists theorize that this solar geoengineering could have a side effect of whitening the sky during the day. New research from Carnegie’s Ben Kravitz and Ken Caldeira indicates that blocking 2% of the sun’s light would make the sky three-to-five times brighter, as well as whiter.