Watch Christopher Nolan and Kip Thorne Discuss the Physics of Interstellar

There’s no arguing about the blockbuster status of Interstellar, director Chris Nolan’s latest box office phenomenon. But plenty of people are debating the science component of that sci-fi tale—which is how it always is when a movie based in something as non-negotiable as physics has to take just enough liberties to make the fiction part of the story fly.

Nolan was determined to keep his narrative scientifically honest, which is why he signed on as technical adviser celebrated Caltech physicist Kip Thorne—who literally wrote the book on (much of) the movie’s cosmology. TIME’s Jeffrey Kluger sat down with Nolan and Thorne to talk about human curiosity, the art of sci-fi filmmaking and the one time the two of them locked horns over a plot point.