There is a scene in Mission To Mars which completely aggravates me because it defies very simple physics involving velocity, acceleration, and relative speeds.
The scene:
Four astronauts are drifting in space and need to hook up to a spacecraft using only their spacesuit thrusters. Time is critical because they are in a decaying orbit. Tim Robbins uses all of his thruster power to manuever toward the craft and hooks a tether to it (the tether is attached to the other three astronauts). But Tim Robbins is unable to hang on and tumbles away from the craft. Good so far.
When the other three astronauts reach the craft, one of them tries to rescue Tim using her suit thrusters. After using 49% of her power (and her “Point of No Return” light lights up) she still hasn’t reached him, so she uses her grappling gun to shoot a tether to him, but the line falls short by a few feet, thus the rescue attempt is unsuccessful.
The problems:
If she had used 49% of her power accelerating toward Tim (away from the craft), she never would have made it back. She was traveling at a fixed velocity away from the craft, she would have had to use another 49% power accelerating back toward the craft just to match its velocity. Then she would have had only 2% power to manuever toward the craft.
Even if she had reached Tim, it would require double the power to get them back to the craft (because together they would be approx. double the mass of just her). And taking point 1 into account, her 51% power would have only halved their velocity … they’d still be drifting from the craft, just at half the speed.
When she was accelerating toward Tim, she SEEMED to be closing the distance between them, but when she stopped thrusting at 51% power, their distance stayed equal, therefore she had matched his velocity. In reality, the opposite would happen. The distance between them would grow until she matched his velocity.
Assuming point 3 never happened, she could have saved him if she immediately shot the grappling line to him from the craft. While she was spending time accelerating towards him, he was drifting farther from the craft (and her). When she finally decided to use it, she was short by only a few feet.
To sum up all four points, the movie writers treated it as a situation of distance rather than velocity and acceleration. And what really bugged me about it was that the movie seemed like it was trying to be as scientifically accurate and realistic as possible. But the scene is completely absurd when you break down the logistics of it.
Dave didn’t blow the door to bits, he activated the explosive bolts to detach the door from the pod. Explosive bolts contain a tiny amount of charge, just enough to fracture and split the bolt itself. There may be additional charge (or even a separate rocket thruster) on the door to push it away from the pod, but that wouldn’t move the pod.
As for Mission to Mars, didn’t it have the “This looks like human DNA” scene? I really hate that. (In this case, they are pointing at a model of a DNA molecule maybe half a dozen base pairs long.)
But the door just…vanished. First there was a door, then there was this huge cloud, and out popped Dave. He bounced around the airlock for a few moments, and that was it. If the door wasn’t destroyed, where did it go? Yeah, now that you mention it, if it was intact, the thing should have been right there with him, which could have been quite a hazard…oh hell, now I’ve gotta watch again and see where the door went.
That’s a pet peeve of mine, too, but I honestly don’t remember that being in the movie. If so, then that’s easily the worst error.
Also,
Right there, you’ve probably already got an error. Orbits don’t decay, unless they’re very close to a black hole or similar object, or there’s some non-gravitational force at work. Now, if you’re too close to a planet, you might get some drag from the uppermost wisps of atmosphere, which can cause an orbit to decay, but the cliche of the decaying orbit shows up far more often than can be justified by that. In orbit, not only does what go up must come down, but also what goes down must come up.
Oops, i rewatched that scene and i was wrong about the decaying orbit bit. The spacecraft was in orbit around Mars and Tim Robbins was drifting away from the craft towards Mars. It would have taken the three astronauts half an hour to get the spacecraft up and running and by that time Tim would have hit the atmosphere. I’m not sure how plausible that is though, as Tim couldn’t have been traveling at more than 15 mph in relation to the craft.
FWIW, Starship Troopers was closer to a parody of an SF film than it was an actual non-meta SF film, so it’s pretty well critic proof on that account.
But one of the things that always bothers me is that in any movie where someone is shrunk down to bug size–except in A Bug’s Life–their environmental viscosity shrinks with them. When a person is shrunk to about the size of a drop of water, any water they interact with has drops in perfect proportion to their decreased size, instead of being a near solid. Instead of being trapped by surface tension, they’re just as likely to splash through the water as if full sized. Ditto things like cloth: the finest silk would be stiff as cardboard to them, but this is never the case.
Similar things happen with any kind of SF transport, like teleportation or whatever: the clothes always go with the body; ditto when there’s invisibility. Sometimes it makes sense, when the mechanism is shown to treat all the matter in question. But sometimes it doesn’t, and logically only the flesh of the subject would be rendered invisible, or elsewhere.
Another invisibility thing: In Hollow Man (which at least got the clothes thing right), the bright light burns his eyes because his eyelids are, of course, transparent. Well . . . if his eyelids are transparent, so are his eyeball parts: he’d be unable to see at all because the light would pass through his retina, which only works because it’s opaque. Ditto the refractablility of the lens, cornea, etc. If he saw anything, he’d see only totally unfocused white light.
OK, I watched the Bowman-in-the-airlock scene again, and that door just ain’t there once the bolts blow. One gets the impression from watching the scene that there’s a big blast of smoke/steam or very fine debris entering the airlock, but nothing big like a slab of metal. Whatever it is, it’s gone pretty fast as Dave flies in, and there’s nothing bouncing around but him. That door is either blown into a powder, or it flew so fast at the camera one cannot register it. But if that were the case, it would probably make a nice divot in the other side of the airlock, so I can’t imagine that’s what happened. Mysterious.
Hamish calls these “mosquito errors,” from a Far Side cartoon in which a male mosquito enters his house, hangs up his hat, and tells his wife, “What a day! I must have spread malaria across half the country.” Numerous readers wrote in to remind Gary Larson that it was the female that bites, not the male; of course, the idea that mosquitoes live in houses, wear clothes, speak English, etc., is perfectly reasonable.
To be fair, Nothing can kill the ARNOLDNATOR! Any wounds he gets will be little more then a scratch.
What bugs me in Airplane 2 is how Simon thought he was going to get back to earth in that stupid little escape capsule from that close to the sun after that premature ejection.
Solo and Co. In the original script, it makes specific reference to Obi-Wan’s sidelong glance at Luke as a reaction to Solo’s “obvious exaggeration” or somesuch.
Now, whether the exaggeration was meant to refer to the “parsecs as time” thing, or just bragging about an impossibly fast speed necessary to satisfy the “parsecs as distance” thing is undetermined. However, people that think they’re OH-SO-SMART for putting two-and-two together are unnaturally resistant to the idea that there’s a perfectly acceptable and sound explanation for either.
Yes! One of my big pet peeves. No tissue damage, no lingering pain or any indication that their heads and eyes almost exploded.
Usually I’m one for saying “If you wanted reality, what were you doing at a movie?” and let us be real and say that there was so very much non-sense in Total Recall, but that one point always annoyed me.
Hell, I didn’t care about that. I was more annoyed by the bit when Ahnuld first arrives on Mars in disguise and goons start shooting. If breaking the dome is so ridiculously easy, why are firearms so commonplace? How hard would it be for one of the rebel sympathizers to go on a kamikaze mission and hole Randy Weaver’s dome, with him in it? Further, a whole bunch of alarms go off instantly when the dome is breached, yet in order to close the blast doors, someone has to manually hit a button? Shouldn’t the doors descend automatically when the alarms go off?
And of course Sharon Stone wasn’t tied up nearly enough, but that’s more aesthetic than factual.
I’ve had a problem with the “big glass dome” model in any circumstances. The thinness of the Martian atomosphere makes it possible for bits of space debris that would never be a threat on Earth to reach the surface at very high velocities. Something with the kinetic energy of a bullet reaching the surface is probably a very rare event for any given patch of Martian soil; but when you make the target square kilometers in size, and leave it there for decades, the probability a few or many such rocks will hit it must approach 1 over the lifespan of the dome, I would imagine.
Whatever the dome is constructed of, it probably should have some kind of geodesic construction, with independent panels of some strong but pliable material. Certainly glass or anything of such a brittle character would be completely unacceptable over large areas, because the energetic formation of even a tiny perforation could lead immediately to cracks, which would rapidly enlarge with stresses, and a huge portion of the dome would simply blow out due to the pressures behind it.
Bugs bunny is in an airplane doing a power dive , and bout 80 feet from the ground he pulls the emergency brake, of course the airplane stops on a dime , defys gravity by hanging in mid air.
Bugs: Whew. Lucky this thing had air brakes!
The bit (and much of the footage) was recycled from an earlier Bugs toon called “Falling Hare”. The bomber plunges yet screeches to a halt in mid air:
Gremlin: [the tiny saboteur Bugs has been chasing throughout the cartoon, addressing audience] Sorry, folks. We’re out of gas!
Bugs: Yeah. [points to a wartime gas ration card] You know how it is with these A-cards!
