Well, to be fair, I didn't remember nine times either. I think the Death Star thing was more of a pressure issue than a knowledge one.
I have found that pop knowledge is as subjective a topic as you can find. What you assume to be common knowledge (or good pop knowledge) may not necessarily be the same to another person. For example, I always assumed that everyone could name the Beatles. I mean, I was born in 1970, my parents didn't even play music in my house growing up, but as far back as I can remember "JohnPaulGeorgeAndRingo" may as well be a word in the dictionary. Yet I find lots of people, people who of the appropriate age, people who are fans of music that directly owe lineage to the Beatles, people who are otherwise reasonably intelligent and seem to know basic world facts, who can't name the Beatles.
On Monday's show, I missed one question (Jacob's Ladder, for the record). On Tuesday's, I only knew two of the AI questions, forgot the number of absences, couldn't tell you Bonnie and Clyde from Bob and Carol and froze on Kathy Bates' name (I'd like to think I would have remembered it in time, though). Knowledge is relative, pop knowledge doubly so.