Buses jumping a 15 meter gap in a highway, as in Speed? No way. Humans plummeting 80 stories without a single broken bone (Spider-Man 3)? Uh-uh. What about Tom Cruise and Dougray Scott walking away from a 160-kilometer-per-hour midair motorcycle collision (Mission Impossible II)?
”Applying Newton’s second law, this collision would result in accelerations of around 200 g’s,” calculates Adam Weiner, a high school physics teacher, lecturer, and author of Don’t Try This at Home! The Physics of Hollywood Movies (Kaplan, 2007). ”150 g’s is usually fatal.”
Weiner is part of a small cottage industry of scientists and educators that includes James Kakalios (The Physics of Superheroes), Lawrence Krauss (The Physics of Star Trek), and Philip C. Plait (Bad Astronomy: Misconceptions and Misuses Revealed, From Astrology to the Moon Landing ”Hoax”), who delight in poking fun at the science-defying feats of action stars and superheroes.
On 6 August, Weiner spoke at ”When Worlds Collide: The Science of Movies,” a seminar at the Los Angeles headquarters of the Academy of Motion Picture Arts and Sciences sponsored by its Science and Technology Council. He asked the 1000 attendees who filled the theater, ”How many of you have seen a movie and wondered if that was physically possible?” Applause. ”How many have seen a movie and thought, ’That’s completely ridiculous.’?” Bigger applause. ”That’s what this talk is about!” he said, laughing.
”We all know Superman isn’t real, but when we watch a movie like The Core, where they’re portraying things that are seemingly scientific, they have a greater obligation to get it right,” Weiner said during a prepanel reception. ”For example, in The Core, they say, ’The frequency of seismic waves changes as it goes across an interface,’ when it’s actually not true. When a wave goes across an interface, the frequency is constant, but the wavelength changes. It wouldn’t hurt the plot to get that one right.”
Weiner acknowledged films that have gone out of their way to be scientifically accurate: 2001: A Space Odyssey (for its rotating space station to approximate gravity), Apollo 13 (which depicted weightlessness through parabolic flight and exquisitely counterbalanced platforms), and Titanic (for explaining how the added weight of flooding seawater exceeded the buoyant force, causing the ship to sink). So why does Hollywood so often get its science wrong?
”Usually, there’s no pressure to have films scientifically accurate—it’s more about art than science,” said stunt coordinator Dan Bradley, who served as second unit director for The Bourne Ultimatum. ”In my work I try to keep it feeling real, like paying attention to how fast things fall. But it’s about entertainment. What reality is to a movie audience has more to do with other movies they’ve seen than what real life is. That’s really the crux of the problem.”
”Much of my job as special effects supervisor is to violate the laws of physics to serve the film,” said Matt Sweeney, who has earned three technical achievement awards from the Academy. ”Take the example of an explosion in space. If an audience sees an explosion, they expect to hear a sound. They don’t realize there’s no sound in space. So you gotta have it; it’s art, not science.”
Still, the seminar provided some hope for purists. A number of other attendees—including Oscar-winning visual effects supervisors Robert Legato (Titanic) and Scott Stokdyk (Spider-Man 2), Oscar-winning special effects supervisor John Frazier (Spider-Man 2), and Oscar-nominated special effects supervisor Shane Mahan (Iron Man)—described their attempts to apply scientific and engineering principles to scenes that seem to break all known physical laws.
For Spider-Man 3’s ”birth of Sandman” sequence, in which a human figure is formed out of sand, Stokdyk studied the movement of sand. ”No science could possibly explain what the movie depicts, but we grounded it in the physics of what sand really does,” he said. ”There was an art and a science component—for example, dry sand will never have a steeper angle than 30 to 38 degrees. We studied real sand fluid simulations, then matched it on a computer.”
For Iron Man, Mahan studied the movement of wing-suit skydiving, which achieves lift through fabric sewn between the legs and under the arms, to better approximate Iron Man’s flight sequence. So perhaps Hollywood just needs to find more joy in scientific accuracy. Todd Hallowell, an executive producer and the second unit director of Apollo 13, recalled a special screening of the movie for astronauts. ”Afterward, a guy came up to me and shook my hand and said, ’You guys got it right.’ I said, ’Well, thank you very much.’ He said, ’By the way, my name’s Buzz Aldrin.’ It was probably the greatest compliment I’ve ever had in my life.”
About the Author
Susan Karlin, based in Los Angeles, contributes frequently to IEEE Spectrum. She recently wrote for us about superheroes, scientists, and comic books in, ”The Design and Engineering of Superheroes.”