What’s that stuff?

B. Ralph Chou is an expert on how to watch eclipses safely. Not only did the professor emeritus of optometry and vision science at the University of Waterloo write the safety standards for eclipse glasses, he's also an eclipse chaser. Chou has seen 30 solar eclipses in his lifetime, and counting. "The only places in the world that I have not touched yet are India and Antarctica," he says. "My passport's got all sorts of interesting stamps." Chou's next eclipse will be the April 8 Great North American Eclipse, during which much of Mexico, the US, and Canada will experience at least a partial eclipse. Around 31 million people live in the path of totality , the area where the sun will be completely blocked by the moon. Many more are expected to travel to the area of totality (Chou is going to Texas). If you're one of these millions