Twilight serves as a liminal time, between day and night—where one is "in the twilight zone, in a liminal nether region of the night". The title of the television fiction series "The Twilight Zone" makes reference to this, describing it as "the middle ground between light and shadow, between science and superstition" in one variant of the original series' opening. The name is from an actual zone observable from space in the place where daylight or shadow advances or retreats about the Earth. Noon and, more often, midnight can be considered liminal, the first transitioning between morning and afternoon, the latter between days.