What does Drexel physics professor Dave Goldberg, PhD, have in common with George R. R. Martin, Stephen King and Guillermo del Toro? They all recently helped rank ‘The 100 best sci-fi movies’ for Time Out magazine.

Goldberg, who specializes in theoretical cosmology and astrophysics, was one of over 130 international movie and television personalities, scientists, science-fiction authors and film critics who were polled about their favorite flicks. The sci-fi enthusiasts used their own favorite movies to contribute to the publication’s list, which included movies as old as 1927’s “Metropolis” and as recent as 2013’s “Gravity.”

The participants were asked to describe their top 10 films, picked using their own definition of what a good sci-fi film would accomplish. To write his own, Goldberg, who is also the director of the undergraduate physics program and associate dean for research and graduate education in the College of Arts and Sciences, prepared by reading other top 100 lists. He even held a roundtable discussion with graduate students.

“For me, science fiction includes any film that uses either extraterrestrial life or as-yet-unknown technology to forward the plot, whether or not either element is at the heart the film. To be truly great sci-fi, I feel as though the internal rules of the world need to be well-established and most importantly, self-consistent,” he said.

One of the best examples? “The Terminator,” which Goldberg says “is the most outstandingly self-consistent time-travel narrative out there.” On the other end of the spectrum lies “Back to the Future,” which he thinks is “a mess in terms of self-consistency of the time-travel rules,” but is still a great movie.

Goldberg came up with a list that was so diverse, it would be too hard to rank them — and it was a sound list, too, since all of the titles made their way onto the list.

Here are his choice movies, listed chronologically: