Excerpt from Chapter 1:
THE NOBLE CAUSE:
Striking a Blow for Decency in Movie Physics
IT'S ONLY A MOVIE
"It's only a movie," is often spoken by fans in defense of flicks with flaky physics, as though reviewing movies for physics content is an insult. But isn't the fact that Hollywood thinks they can feed us stupid physics the real insult? Let me explain why reviewing movies for something they need is not insulting, or unnecessary-starting with a hypothetical. Imagine a football movie: a group of plucky individualists have been forged into a team by the tough yet big-hearted coach. No one gave them a chance; yet, here they are in the big game playing their hearts out as Murphy, their beloved teammate, lies in the hospital with bandaged eyes, listening to the contest via radio.
The team is behind and desperate. It's the seventh down in the eleventh quarter, so they punt a touchdown pass from the 127th yard line. But wait, this isn't football. It's nonsense. Anyone with football knowledge would think it was ridiculous; some would be offended. The scene would never appear in a movie-not because it's unlikely or hackneyed, but because it's unthinkable to take artistic license with the rules of football. (For those who don't favor American-style football, substitute basketball, soccer, hockey, or just about any other team sport. With a few modifications, the plot will still work.)
Artistic license isn't a driver's license; it's an ambulance license. It grants the right to break rules without suffering petty penalties like traffic tickets. But rule breaking can cause errors, leading to serious penalties: wrecks. Rule breaking requires care; it's not a good idea unless there's a good reason. Hollywood would never take such a gamble with the manmade rules of football.
So, when it comes to something profound like the guiding rules of the universe, why, of course, break the rules at will-no risk here.
Okay, I realize that Hollywood isn't likely to reform, but at least by discussing bad movie physics it's possible to repair some of the damage done to our clear thinking by constant exposure to foolishness. Sadly, Hollywood has a rational reason for affording more respect to the rules of football than the laws of physics: audiences are more likely to know them. Ironically, movies may be part of the cure for this ailment: Hollywood's bad physics examples are good physics teaching tools. Besides, movies are almost as entertaining as physics, so what could be more fun than combining the two?
In 1997, after years of watching one Hollywood physics wreck after another, I took a stand for decency in movie physics by founding what has become the premier movie physics site on the Internet. Since American moviegoers are used to rating systems warning of possible affronts to their sensibilities from strong language, violence, and sexuality, and since warning systems are, of course, highly effective deterrents, how could I resist? I created a similar system to warn about affronts from bad physics. Well, maybe ratings aren't so effective but at least they're fun.
Movie Physics Rating System:
GP = Good physics in general
PGP = Pretty good physics (just enough flaws to be fun)
GP-13 = Children under 13 might be tricked into thinking the physics were pretty good; parental guidance is suggested
RP = Retch
XP = Obviously physics from an unknown universe
NR = Unrated. When a movie is obviously a parody, fantasy, cartoon, or is clearly based on a comic book, it can't be rated but may still have some interesting physics worth discussing.
THE IMPACT ON ARTISTIC QUALITY
To understand when the rules (the laws of physics) should not be broken, it's best to start with the situations where they can or should be. These include cartoons, parodies, and fantasies. Even top-notch science fiction routinely stretches the boundaries of physics for the sake of story.
Time-travel is a good example of acceptable physics-bending for the sake of story. Ask ten physicists about time travel and you'll get eleven different answers, and that's with two abstaining.
The truth is nobody really knows for sure if it's possible, let alone how to do it. Without it, however, there would be no Terminator movies, a definite loss of some great cinematic moments (not to mention catchy gubernatorial campaign slogans). In The Terminator [PGP] (1984), computers/machines have developed consciousness and a need for entertainment along with it. What to do: work a few math problems-for a computer, how mundane-or kill off humanity? It's a no-brainer: kill people.
Unfortunately, those irascible humans are unenthusiastic about extinction. A human leader steps forward and pulls together an effective resistance movement.To remedy this affront, the machines send a terminator-a metal robot covered with living tissue (Arnold
Schwarzenegger)-back in time to assassinate the resistance leader's mother and snuff the movement before it starts.The humans, somehow, get wind of the plot and send back one of their own to protect the mother. Both protector and terminator arrive naked since, according to the movie, anything nonliving has to be surrounded by living tissue in order to be transported backwards through time. (Evidently hair, dead skin, and fingernails are the exception.)
Okay, the business about having to surround metal with living tissue and only send naked people back in time has no scientific basis, but it's necessary for the film's central conflict. If the human could carry a futuristic weapon, he could easily blow away the terminator and spoil the fun. Instead, he's a rabbit desperately trying to avoid the jaws of a bloodthirsty wolf in possibly the highest intensity chase ever filmed.
The nakedness also taps into the deepest levels of the human psyche. Imagine arriving naked, not just at work or school but in an entirely different era. The moviemakers do the arrival scene right: they depict a gray area of physics, time travel, with a minimum of scientific mumbo-jumbo and considerable artistic purpose. It's another matter to defy well-established physics principles for no good reason. Any bright high school physics student (probably not a target audience) can easily spot such foolishness. Many people feel it-like an annoying itch-even when they have no physics background whatsoever. They may not be able to verbalize reasons but have experienced gravity, velocity, acceleration, force, and energy firsthand their entire lives. Individuals with military experience-shooting guns, setting off explosives, flying helicopters-are especially cranky about the itch. Here's a scary thought: in spite of physics' reputation for difficulty, it's really not all that hard to learn; verbalizing soon follows.
