Nouns are parts of speech used to identify and name a class of people, things, places. The nouns in this sentence are MOON which is the subject, CRATERS, and SURFACE. It can be easily identified if an article can be used before the noun
I think he travels by boat
Rumor has it that Lady Bracknell was a combination of Wilde's own mother, Lady Wilde, and Lord Alfred's own mother, Lady Queensberry. Seems like his mother takes the cake on the dead-on character for this