Neil deGrasse Tyson, the director of the Hayden Planetarium, at the American Museum of Natural History, is the host of “Cosmos: A Spacetime Odyssey,” on Fox, which is a sequel to Carl Sagan’s celebrated PBS series. Tyson’s rhetorical style differs dramatically from Sagan’s. Sagan paid deference to high culture; Tyson’s preferred frame of reference is pop culture. This does not mean that he has unsophisticated tastes. But when explaining science he is most likely to point to a movie such as “A Bug’s Life.” Tyson meets people where they are, rather than seeking to raise them to where he is.