While there are no scientific studies that link spaceflight to graying hair, NASA has previously suggested that spending time in space can cause “significant physiological changes.” “Imagine if all of your physiological changes were hyper-accelerated so that you passed through life cycles in weeks as opposed to decades,” NASA wrote online when the agency announced it would be launching a “space-age” research program to study space’s effects on the human body. “You’d be able to grow a beard overnight or your hair might begin graying in a matter of days or maybe menopause would come knocking by next weekend.” NASA...