I agree with you about the disjointedness of the second half (and mainly the last third) of the book. I can see why it would be difficult to work that stuff into a chronological narrative very easily, which is why he broke away from that after a while, but it ended up more like a collection of essays than the story that began at the front of the book.

I would also have loved to see more about what he actually does all day! I may have a better idea of that than you, having spent quite a bit of time hanging around the physics and astronomy departments in college, but it’s still hard for people to imagine. (My guess is he gets a lot of ‘Director of the Planetarium, huh? So you… describe what people are seeing there?’ just like librarians get ‘it must be nice to sit around and read all day’.)