As David Sibelius boils the lobsters for the annual dinner he hosts for his graduate students at the Boston Institute of Technology, his 12-year-old daughter, Ada, observes him with a sense of foreboding.

Whether Orion ought to be feet- or head-up in the night sky depends on the hemisphere. When Stan, a 23-year-old student from South Australia, rides his bike through the Rocky Mountains, he marvels that the constellation is upside down.