The exhibit, "Cosmic Collisions: The Impact of the Planets" debuted in 2000, and the controversy surrounding Pluto's exclusion began to surface shortly after. It's likely that many people noticed Pluto's absence, including members of the public, scientists, and journalists, but there is no definitive record of who was the first to point it out.
The controversy surrounding Pluto's status as a planet was already present at the time, and the exhibit likely served as a catalyst for the public debate. It is important to note that Tyson himself was not solely responsible for the decision to exclude Pluto. It was a collaborative decision made by the entire curatorial team.
