Physics vs. Fantasy

Physics professor Sean Carroll is Hollywood’s reality check

Dr. Sean Carroll

Sitting in the studio conference room, Cal Tech’s Prof. Carroll winced at the staff of Thor. No way could the Norse warriors drive a bunch of Frost Giants off the edge of a planet. C’mon. There’s this thing called hydrostatic equilibrium, see. It means that gravity tends to pull large masses – a.k.a. planets – into a spherical shape. But even if it was flat, gravity would keep the inhabitants securely upon it. “The Frost Giants wouldn’t fall off the planet,” Carroll explained. “They’d just be standing on the other side.” There was considerable grumbling, but science won. In the movie, the planet is round.

Sean Carroll was first called out of his classroom in 2007. Invited to lunch by Ron Howard and others working on the film adaptation of Dan Brown’s Angels & Demons, he was asked about an antimatter bomb that threatens to level the Vatican. Say what?

Well, let’s see.  Antimatter explodes in contact with air. A single gram of the stuff equals 40 kilotons of TNT. Think 3x the Hiroshima bomb. But in 30 years, CERN’s Large Hadron Collider in Switzerland has only produced ten billionths of a gram. So what would an antimatter bomb look like? Basically, a brief and harmless fizzle. But, okay, say you DID have an entire gram. It would have to be suspended in a magnetic field until set loose. And it wouldn’t be a single boom, but a series of blasts as air was pushed out by each explosion. Two years later when the film came out, Carroll was gratified to see he’d been heard and heeded.

Now that Prof. Carroll is on the studio’s radar, he’s been called in for a host of movies and TV shows, like: Tron: Legacy, Dr. Strange, and The Big Bang Theory.  For an episode of Bones, he had to devise a murder method – a form of radioactivity with a half-life too short to leave traces.

But let’s be perfectly clear. Sean Carroll’s job isn’t to make the science in movies real, but plausible. As David Kirby, author of Lab Coats in Hollywood, explains, “Audiences are willing to release their grip on reality for a few hours – but only to a point. Defy the laws of planetary physics and your blockbuster could go the way of Battlefield Earth, Superman IV, and other Hollywood punch lines.”