Favorite "defy-physics" Movie/TV plot hole? (SPOILERS!)

Cafe Society
1

Although this could be a pit thread, I figured that it’s a common enough problem not to raise my ire to pit-worthy depths. It also could be IMHO, but seems to fit better here. I apologize if I guessed wrong.

In short, what’s your favorite blantant misuse of physics for the sake of a movie or TV plot point?

To get things started, how about X-Men 2 (caveat… I liked the movie but this bothered me):

The X-Men jet is capable of at least mach 4 flight and is radar and heat stealthed (according to the first movie). Why could two F-16’s stay with it? Why can two sidewinder missles lock on, fly straight, level and true through tornado force winds and hit a stealthed target that should be faster than the missles? Why didn’t the bullet simply flatten (or ricochet) off of Wolverine’s adamantium laced forehead?

And, perhaps the last James Bond film, Die Another Day, when:

The claim is made that a hovercraft won’t set off pressure mines because it “floats”. How about Newton’s laws people? A hovercraft’s weight doesn’t magically disappear. The air pressure under the skirt has to equal or exceed the weight of the hovercraft, thus having enough force to set off weight detonated mines.

Of course, the entire Star Trek franchise wins hands down, so please pick specific incidents that bothered you.

2

Originally from the “Cartoon Laws” thread, but it has made its way into “live” action movies as well. When someone with superhuman strength picks up an object (train car, building, truck, whatever) and moves it as if it were made of styrofoam. The object moves as if it were one, solid piece and the person’s feet don’t sink into the ground or anything. Sheesh.

Can’t think of any specific examples at this hour of the morning, but I know they’re out there.

3

I like the scene in Jaws where the shark comes out of the water…and growls. Sharks don’t growl.

4

Getting annoyed at this sort of thing is taking anal retentiveness much too far. They’re fun to point out, but if it bothers you, you should really just relax.

In any case, the basic premise of Space: 1999: The moon leaving orbit and traveling at FTL speeds. The show also showed a quart-sized bottle labelled “10 litres” and – not a scientific error, but a construction one – showing a structure built on the moon with windows that could be opened. The show beats Star Trek by a mile.

5

Well, the horrible “Lost in Space” movie comes to mind. Flying through an exploding planet? That’s wrong in just so many ways.

6

What seems to bother me the most is when a major plot point revolves around a seriously flawed interpertation of physics or science. I don’t mind the occassional “noise in space” or “making the kessel run in less than 12 parsecs”. But when the whole excuse for a five minute chase scene is based on a premise that would get you killed quickly, I find that I don’t enjoy the chase scene as much.

I can suspend my disbelief as long as the movie/tv show doesn’t force me out of that disbelief by relying heavily on seriously flawed ideas for major plot points.

And that’s anal-retentive to you. :wink:

7

There’s my point. There’s nothing scientifically wrong with that statement.

True, a parsec is a measure of distance, not time – in our universe. But Star Wars is specifically set in a universe “Long ago and far away,” so there’s no reason why their unit for time is not a parsec.

Science fiction is a literature of imagination (among other things), and it grieves me when people refuse to use theirs when watching it.

8

Armageddon.

That a single thermonuclear device could split an asteroid the size of Texas, as well as vaporizing all of the bazillion asteroidlets that are merely the size of, say, Rhode Island, even though they were on the other side of the asteroid from where the explosion took place and some were, in fact, days ahead of the asteroid in its trajectory.

9

I always thought Han was talking about making it under the shortest distance through the Kessel Run. For example, say the expanse was 5 parsecs but is extremely difficult to navigate cuz of some natural phenomena. A lot of the ships might have to make all sorts of crazy course corrections which would end up having the ships to travel like 15 parsecs to safely navigate through the Kessel Run. Han would be bragging that it took him a shorter distance to cross the KR by taking risks.

10

The Matrix. [spoiler]We build solar-powered supercomputers with AI. Then the sky goes out for some reason I can’t remember, and the computers need a new way to get energy. So they enslave all the humans and place us in a state of suspended animation, and get energy out of our brains somehow. And how do they keep us alive? By feeding us liquified newborns and dead people. IOW, the plot revolves around mankind being used in a devilish perpetual motion machine. Go go go second law of thermodynamics!

Not to mention the fact that humans are ALSO solar-powered. We get our energy from the sun and from eating plants and animals, which in turn got their energy from the sun.[/spoiler]

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True, but wasn’t that statement a reply to Luke questioning the speed of the ship?

“Is she fast?” You mean you’ve never heard of the Millenium Falcon?"
Of course, my memory may be faulty.

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Actually, I remember a particularly ingenious fan explanation for this, suggesting the Kessel Run was a shipping route through a region with one or more black holes. You could take the long way around (if you were chicken) or you could fly your ship very fast and very close to the singularities, taking a risky but efficient “short-cut”; in this case, a mere 12-parsec distance. The pilot who can take the straightest possible course is worthy of fame.

In any case, Han Solo’s boast isn’t critical to the plot and is hardly worth complaining about.

In a TV series like V or a film like Independence Day, interstellar aliens come to Earth in order to plunder it. which is strange since they could much more easily collect all the resources they need just by wandering though the asteroid belt or by grabbing a few comets.

13

That’s not what I was trying to get at. My problem is not with science fiction, just with the liberties taken with science. I can use my imagination and come up with dozens of ways that a parsec could be a time or distance measurement and the sentence would make sense. At least one Star Wars site even claim that the parsec is a distance measure used for a specific set of intercepts with moving targets. So a short distance implies both great skill and speed. It upsets most people because everything else is normal English. So it comes accross as a technical word used incorrectly. But it’s minor and can be ignored.

I can think of no way that a hovercraft could travel over a minefield without triggering the pressure mines.

One is a minor point of semantics that is easily glossed over. The other is a fundamental mistake that provides the basis for a major scene in the film.

I can live with one but not the other. That’s where I was going with this thread.

Some more examples (from Star Trek, because it’s so illustrative):

Acceptable: Ignoring time dilation and relativity. If you don’t go there, I won’t either.
Not Acceptable: Having one random episode where relativity suddenly plays a major plot point… forcing the viewer to wonder about all those other times where it was completely ignored

Acceptable: A mutagenic virus that can transition from species to species. Possible with some imagination.
Not-acceptable: A virus that forces the “introns” of your DNA to express themselves forcing you to “devolve” into an ancestor creature. There are so many things wrong with this plot line from a DNA/Evolution/Biochemistry/Mass balance perspective that it can only be described as Treknobabble. Two minutes of research on google, or a basic biology book would have made the writers realize the plot was dumb.

As long as the book/movie/tv show is internally consistent and doesn’t force me to recognize major violations of the laws of physics, I’m happy. But when I’m left wondering whether the script writer had a high school science education, I’m not mentally in the story anymore. It’s not a failure of imagination, it’s more a case of wanting a quality product.

14

Everything in Independence Day. If the ships were as large as they were, the pressure would have totally flattened everything beneath them: they were utterly huge and extremely close. Oops. There are a lot of other major flaws explained at the movie’s entry at www.imdb.com.

15

How about Eraser? I haven’t seen it in a while, but I remember these two:

  1. Arnold falls a rather large distance out of plane at one point without a parachute and lands on a car. No major injury.

  2. There is a shoot-out between two people in a hall, on either side of a bulletproof glass wall. Of course the wall stops their bullets from hitting the other guy, but I’ve always thought they’d both be dead from the ricochets.

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Everybody, on three: “A WIZARD DID IT!”

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If you’re gonna make up a unit of measurement, don’t give it a name that’s the same as a unit for something that really exists. Either that, or don’t use real units for your fictional system. Any way you look at it “Making a Kessel run is 12 parsecs” is dumb. It’s distracting to those of us who know and use parsecs.

At least it’s not confined to Star Wars. In Battlestar Galactica they used “microns” as a unit of distance. Of course, "microns’ is a unit of distance – it’s one millionth of a meter, or a thousandth of a millimeter.
So when Lorne Greene told us that the bad guys were “12 microns away”, you wanted to go into Maxwell Smart mode and say, “Missed it by that much!”

18

I haven’t seen the film in question, so I’m not certain of the specifics, but I don’t think you’re fully considering the specifics of the situation. A hovercraft obviously still exerts pressure on the surface it operates over, but that pressure will be vastly less per square inch than a vehicle or person. The weight of the vehicle is being distributed over the entire surface area of the cushion, not just the square footage of a treads/wheels/feet/whatever in contact with the ground. It is the same principal that makes snowshoes and skis work, gave the T-34 tank superior performance in mud and snow, and allows hovercraft to travel over water.

A quick estimate based on my own feet would be a surface area of around 60-70 square inches (podiatrists/shoemakers/etc. are welcome to provide better data). At a weight of 175 lbs, that would mean I exert a pressure of about 2.5lbs/sq in. standing normally. Lift one foot to walk, and I double my ground pressure. Walking with a normal gait, heel to toe, probably at least redoubles my pressure, and momentum might increase it still further. Given that it wouldn’t be desirable for a landmine to go off at the slightest touch, lest it be detonated by mice, falling leaves, or freezing earth, it could effectively be fuzed to go off under perhaps 3 to 5 pounds of pressure, and perhaps more. Military personnel with knowledge of anti-personnel mines, please feel free to contribute.

A hypothetical 3,000 lb (loaded weight, again anyone with real world data please feel free to contribute) small hovercraft, measuring 9’ by 5’, would be expected to exert ground pressure of less than half a pound per square inch. Thus, it would be likely to run harmlessly over just about anything.

Interestingly, while a tracked vehicle’s normal ground pressure might well be almost as low as a person’s, You still probably wouldn’t want to be run over by one. To the extent the tank runs over any “bump”, the pressure on that object would increase as noted above with regard to walking, until that object either gets pressed into the primary surface, or is itself flattened out. I suppose that, on very muddy ground, a relatively fragile object might survive the experience, though.

I gather the same principles could apply to the alien ships of Independence Day, though I would think that anti-gravity propulsion would likely exert no pressure at all. Of course, science-wise, that’s the least of the film’s problems…

19

In Independence day, that would only hold if the aliens were using some sort of reaction-mass throwing drive. I don’t think they were, because if they knew about reaction mass, any sensible alien would have sat in the asteroid belt and pitched rocks at the cities of Earth.

Then again, these are the same aliens who can fly from another planet, but are too stupid to come up with their own communication satellites, so they hijack ours to synchronize their attack.

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Fortunately, the USMC could.