The astronomers talk about remote galaxies and dwarf stars and black holes, and even if we haven't the faintest idea what they are talking about, we take it as given that they have a scientific basis for their claims, and are not just spinning fantasies for our amusement. As a general rule, we no longer accept that something is true or real because someone in a position of authority has told us so. We expect a process of verification that ideally involves replication of the original situation, repeated testing, and correlation with data that have already been established. But on the whole, modern people have demystified the physical universe. As Dawkins has pointed out, memes have lineages, and compete with similar memes for space in the limited attention spans of human populations.
Memes aggregate into more complex memes.
Both religions and cultures are composed of ideas about what constitutes good behavior, what constitutes group identity, what practices are appropriate on certain occasions, and so forth. They deal with what you do, why you do it, and how to do it. None of this exists objectively in the physical world around us. Philosophers have been trying to answer this kind of question for millenia. Plato distinguished between the physical and the ideal, and considered only the latter to be real.