“The best possible material probably is diamond,” Keutsch told me. “Diamonds really will not absorb any energy. So this would minimize the change in stratospheric dynamics. And diamond itself is extremely unreactive. The idea that this is expensive—I don’t care about that. If we had to engineer this on a big scale because it solves a big problem, we would figure out a way to do it.” Shooting tiny diamonds into the stratosphere struck me as magical, like sprinkling the world with pixie dust.
