My comment was way less on what the Greeks knew than on what I think “every teenager” knows. In my reading of the question, the bar is a lot higher than “most

My comment was way less on what the Greeks knew than on what I think “every teenager” knows. In my reading of the question, the bar is a lot higher than “most easily remembered”, even loosening (as we should; there’s basically nothing that truly _every_ teenager knows) “every teenager knows” to “a majority of teenagers know” I can’t find a specific paper on teenager’s knowledge, but if you Google a bit, you get hits such as https://koreascience.kr/article/JAKO201008863879014 https://koreascience.kr/article/JAKO201008863879014, which says “Some teachers thought that the distance to Neptune is farther than the distance from Earth to the nearest star”. Those are elementary school teachers that may not be university schooled, but I would guess they education-wise score in the upper half of the population. https://www.researchgate.net/publication/247914140_The_initial_knowledge_state_of_high_school_astronomy_students https://www.researchgate.net/publication/247914140_The_initi... also is revealing about what teenagers know, but focuses a bit more on understanding.