Neil deGrasse Tyson is the closest thing modern science has to a rock star. To call him this generation’s Carl Sagan isn’t too far off. The Harvard-trained astrophysicist has a unique ability to take complex theoretical concepts and make them accessible to a wide audience, and be totally engaging at the same time. Hell, he even helped reboot Sagan’s Cosmos: A Spacetime Odyssey, which wraps up its 13-episode run this Sunday on various Fox channels.

Over the years, Tyson has also taken it upon himself to chime in on various movies that may not be using science in the proper way, or that have blatantly ignored the laws of physics. He absolutely eviscerated that scene J.J. Abrams’ Star Trek Into Darkness where the Enterprise hides underwater. So you have to assume that, given his penchant for pointing out scientific flaws in movies, he must watch a fair amount of them. Hero Complex took it upon themselves to get in touch with him and inquire about his tastes in the genre. What follows are Neil deGrasse Tyson’s top ten favorite sci-fi movies, in chronological order, with one honorable mention. You may find some of them surprising.

Alan Moore and Dave Gibbons’ Watchmen is one of the most seminal works in comics history. The film adaptation lingered in development hell for years beginning in 1986, up until Warner Bros. acquired the film rights in 2005 and hired Zack Snyder to direct. As much as his changes to the story may have irritated die-hard fans of the comics, the Watchmen movie could have gone a very different direction if Terry Gilliam and Joel Silver’s version had made it to the screen.

While Snyder’s ending changed some of the specifics of how the story ended, it was still operating around the same basic idea: uniting humanity through fear of a threat that endangered our entire species. The Gilliam version, on the other hand, would have involved time travel and, frankly, would have been an enormous cop-out that would undoubtedly have pissed off Watchmen fans even more than the ending we got. The final act of Gilliam’s version would have seen Dr. Manhattan traveling back in time to stop the very experiment that created him, thus effectively negating the entire story we’d seen play out. In a new interview with the Huffington Post, Snyder and his producing partner and wife Deborah Snyder spoke about Gilliam’s version of Watchmen, as compared to their take:

Back in 2009, director Zack Snyder brought his vision for Alan Moore & Dave Gibbons’ Watchmen to the big screen. While Snyder’s film was mostly faithful to the original source material, there were some changes to the ending to make it more palatable for movie-going audiences. The premiere of Watchmen in 2009 was the product of a very long road of production development that changed hands a number of times before it landed in Zack Snyder’s lap. In fact, one of those “roads not taken” could have resulted in a Watchmen film from Terry Gilliam.

The Watchmen film was in development pretty much from the time the comic book series was first hitting newsstands across the country in 1986. Producer Joel Silver and Lawrence Gordon acquired the film rights for Twentieth Century Fox, before it eventually moved to Warner Bros. While writer Alan Moore had no interest in seeing his story on the big screen, screenwriter Sam Hamm (who penned the 1989 Batman) painstakingly condensed 12 brilliant issues into one manageable screenplay. Silver then brought on Terry Gilliam to direct the film, following up on the artistic — if not box office — success of Brazil in 1985.