Science writer Greg Critser knows the world may be a strange place in 2050 if humans are living longer: one in four people will be over 65, compared to one in nine today, and one million people will be 100 years old and up. “What we’re going to see, and what you can already see, is there will be two classes of elderly people,” Critser said. “The fairly poor and the fairly well off.” Critser chatted with Zócalo about his latest book, Eternity Soup: Inside the Quest to End Aging, the age-old human urge to live forever, and its consequences.

*Video produced by Laura Villalpando. Photo courtesy Sebastian Niedlich.