It takes years to make a movie, with hundreds, sometimes even thousands, of people working together.

Amid the strain of budgets, creative disagreements and other aspects of the filmmaking process, small details fall by the wayside.

Realism can be one of the casualties of the process. Who hasn't watched a film and thought, "Come on, that's not possible"?

Films are ultimately meant to entertain, and "the rule of cool” — the idea that what's fun and entertaining is most important — often wins out over plausability.

But sometimes a special group will be called in to make sure the movie gets it right: science consultants.

For many of these professors and researchers, science fiction is the go-to genre.

"The difference between science fiction and fantasy is that science fiction has a basis in actual science," said Mohamed Noor, a biologist at Duke University, who has consulted for two seasons of "Star Trek: Discovery." "[Our job] is to make it so that basis in reality is as accurate as possible."

In practice, that means ensuring ideas presented in the show are either consistent with scientific principles or that a hypothesis about what might be possible in the future is also grounded in current science.

In one episode, the "Discovery" writers were looking for a new alien species with a mysterious disease that would be extremely difficult to cure.

Noor suggested using prion diseases.

These extremely rare diseases are caused by protein mutations in the........

© Deutsche Welle