21stcentury alternativehistories(fiction) cienciaycivilización civilizaciónmoderna civilization enelfuturo extraterrestres extraterrestrialbeings fiction forecasting futur general history human-alienencounters humanbeings modern moderncivilization newyorktimesbestseller newyorktimesreviewed nouvelles nyt:combined-print-and-e-book-nonfiction=2017-03-12 rencontresaveclesextraterrestres romans scienceandcivilization sciencefiction technologyandcivilization tecnologíaycivilización uchronie(genrelittéraire)