It’s 2070. You’re on a train from New York to Boston. If you could see outside, it would be mostly open landscape. Maybe a nuclear plant or two, but otherwise green space—none of the urban sprawl, wind farms, solar arrays or biomass operations we’ve been taught to expect from an ecologically responsible future. But you can’t see outside, because you’re underground, traveling 300 miles an hour on a maglev train alongside superconducting pipes transporting the energy from those nuclear plants.