Charles gazed at the night sky and smiled. It appeared filmy, as if a giant sheet of wax paper hovered between him and the heavens. The hotel balcony, where he stood, gave him a sweeping view of the Gran Vía, the large boulevard that ran through the center of Madrid. Pulsing red, twinkling blue and violet, blinking yellow, speeding white high beams—the street swam with electric intensity below while above all was murky. Nothing shone or twinkled up there. Even the moon was less visible, something he noticed back in New York over a year ago. He didn’t make much of it, not at first, assuming that the moon’s disappearance was an effect of light pollution. Astronomers had long issued warnings: too much artificial outdoor lighting was responsible for transforming pristine darkness into an unsightly wash of cloudy denim. Charles experienced a sense of loss…