The astrophysicist argues that our books and films about interstellar space travel are a form of mass _________, and that only a miracle on a scale heretofore unseen could allow a human being to voyage to even the closest star in another solar system.
The second half of the sentence tells you that it would take a “miracle” for a person to get to another solar system. In other words, it’s more or less or impossible. Both dementia and hysteria are too negative and extreme. Delusion, meaning “a belief that is maintained despite being contradicted by reality,” is the best fit.
