The sky will go dark. The temperature will drop. Stars will shine in the middle of the day. For the first time in nearly a century, millions of Americans from coast-to-coast will witness a total solar eclipse. Those who have watched the sun suddenly snuff out say it’s an otherworldly feeling. It can be humbling. It can be spiritual. It can change the course of history (SN: 5/13/17, p. 29).