It’s a law of physics that there are two types of charges, positive and negative. So, after the acclaim and record box office of Warner Bros.’ “Gravity” this past weekend, an astrophysicist felt compelled to point out that he seems shocked to discover that it’s a piece of fiction.

Neil deGrasse Tyson, director of the Hayden Planetarium and presenter on the series “Cosmos: A Space-Time Odyssey,” offered a series of tweets Sunday night poking holes in various elements of the film. One example: “Nearly all satellites orbit Earth west to east yet all satellite debris portrayed orbited east to west.”

When a film is successful, it inevitably will receive criticism. A favorite target are films based on fact, such as “A Beautiful Mind” and “The King’s Speech.” Critics like to point out that the film does not scrupulously follow the facts as they detail the flaws in the real-life protagonists. Fiction films are cited less often.

Decades ago, David Letterman had a semi-regular segment called “Limited Perspective,” in which guests offered deadpan commentaries on the inaccuracies in some films, such as a dentist pointing out that historical films don’t work because the stars’ teeth are too nice for the period.

An added astrophysics note to movie lovers: In “E.T. the Extra-Terrestrial,” Elliott and E.T. are on a bicycle that suddenly starts flying through the air. Scientifically, that’s not possible either.