The timeline of The Big Bang Theory universe isn’t always easy to track, but Young Sheldon gives fans at least one reliable reference point.
In season 5, Sheldon learns that famous science fiction writer Isaac Asimov has died — an event that occurred in real life on April 6, 1992. The moment is especially emotional for Sheldon, who deeply admires the author and had already been reading works like I, Robot at a young age.
Series co-creator Steve Molaro has said the show intentionally avoids strict dates so that stories can unfold more naturally. Because adult Sheldon narrates the series from memory, the timeline can shift depending on the story being told.
Still, the mention of Asimov’s death gives fans a valuable clue about when certain events in Sheldon’s childhood take place.