One of Jimmy Fallon's recurring segments, "Pros and Cons," finds him listing, well, the pros and cons of various topics. On last night's episode of The Tonight Show, Fallon chose to examine a scientific topic—the Hyperloop. First conceived by Elon Musk, the Hyperloop is a high-speed, magnetically levitated train that travels over 700 mph inside a sealed tube. Fallon chose the topic because a Hyperloop motor was successfully tested in the Nevada desert last week.