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Good Science and Bad Science And Lack Thereof In Science Fiction Films and TV Series

Onyx

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Following on from that (falling and landing suddenly!) in a book rather than film, I recently read a real clanger:



You'd stop accelerating but you wouldn't stop moving and you'd almost certainly be moving fast enough by then for death or at least injury. Reversing the artificial gravity for exactly the right amount of time would work but would also have catastrophic rather than just inconvenient consequences for everyone else.

Frankly if an author/scriptwriter/director can't wrap their mind around basic physics they should avoid Science Fiction.
Aren't you assuming that "artigrav" works like gravity? Artigrav could be so different than gravity that when you remove it your body goes back to the momentum it would have had before entering artigrav.

Author's physics, author's rules.
 

Vertigo

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Aren't you assuming that "artigrav" works like gravity? Artigrav could be so different than gravity that when you remove it your body goes back to the momentum it would have had before entering artigrav.

Author's physics, author's rules.
That wouldn't be consistent with how it behaves in the rest of the book. And you could say that about anything in this thread and indeed anything in science fiction, which is where the grey areas come between hard SF, SF and what I'd describe as Science Fantasy.
 

psikeyhackr

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For me a curious thing about the movie, Gravity is the lack of discussion of when Sandra Bullock's character was supposed to release herself from the Canadarm.


It was broken loose from the shuttle and spinning and Cloony's character was yelling at her to release from the arm like it made no difference when she did it. Since it was rotating and moving in a line away from the shuttle what direction she would be hurled in would depend on the timing.

But for all of the talk about how accurate or inaccurate the movie was Neil DeGrasse Tyson has not discussed that. Yeah, just sling her faster away from the shuttle! :eek:
 

Onyx

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For me a curious thing about the movie, Gravity is the lack of discussion of when Sandra Bullock's character was supposed to release herself from the Canadarm.


It was broken loose from the shuttle and spinning and Cloony's character was yelling at her to release from the arm like it made no difference when she did it. Since it was rotating and moving in a line away from the shuttle what direction she would be hurled in would depend on the timing.

But for all of the talk about how accurate or inaccurate the movie was Neil DeGrasse Tyson has not discussed that. Yeah, just sling her faster away from the shuttle! :eek:
If you're talking about this scene, I would note that Canadarm is rotating around Bullock, not the other way around, so it isn't going to throw her as much as she is going to throw the arm. And she is rotating too fast for an uncomfortable specialist on their first walk to time much of anything.

 

psikeyhackr

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If you're talking about this scene, I would note that Canadarm is rotating around Bullock, not the other way around,
It has been a long time since I saw the movie but if they shot it that way then it is just another error.

The Canadarm is 15.2 m (50 ft) long and 38 cm (15 in) diameter with six degrees of freedom. It weighs 410 kg (900 lb) by itself, and 450 kg (990 lb) as part of the total system.
Canadarm - Wikipedia

The Apollo suit, including the life support backpack, weighed about 180 pounds. The Shuttle suit, including the life support system, weighs about 310 pounds. The suit itself weighs about 110 pounds. If an astronaut weighing 175 pounds wears the complete suit, the total weight is then about 485 pounds (310 + 175 =495).
In reality they would have rotated around their mutual center of gravity which would have had to be a few feet away from her.
 
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Onyx

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It has been a long time since I saw the movie but if they shot it that way then it is just another error.



Canadarm - Wikipedia



In reality they would have rotated around their mutual center of gravity which would have had to be a few feet away from her.
You're assuming that the mass is evenly distributed across the length of the arm. More likely the two ends are the heaviest parts, and the shuttle end was broken off. So if the majority of the arm's mass is left at the claw end, it is going to keep the CG near the astronaut.
 

psikeyhackr

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You're assuming that the mass is evenly distributed across the length of the arm. More likely the two ends are the heaviest parts, and the shuttle end was broken off. So if the majority of the arm's mass is left at the claw end, it is going to keep the CG near the astronaut.
There were 3 mass concentrations; the shoulder, the elbow and the wrist. In the film the upper arm broke leaving the shoulder with the shuttle. The elbow and wrist were rotating with Sandra. Each arm section was about 60 pounds and 25 feet long so the elbow was probably about 1/3rd of 750 pounds. That much weight at that distance would put the center of rotation some feet away from Bolluck. So releasing would alter her trajectory.

The conversation during that scene implied that the arm was carrying her away but they had mutual complex movement. When she released would matter and possibly make it worse at the wrong time. Even if I was making the invalid assumption you accuse me of it would still be true. The wrist was about 5 feet long by itself. You can even see that in the film.
 

Onyx

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There were 3 mass concentrations; the shoulder, the elbow and the wrist. In the film the upper arm broke leaving the shoulder with the shuttle. The elbow and wrist were rotating with Sandra. Each arm section was about 60 pounds and 25 feet long so the elbow was probably about 1/3rd of 750 pounds. That much weight at that distance would put the center of rotation some feet away from Bolluck. So releasing would alter her trajectory.

The conversation during that scene implied that the arm was carrying her away but they had mutual complex movement. When she released would matter and possibly make it worse at the wrong time. Even if I was making the invalid assumption you accuse me of it would still be true. The wrist was about 5 feet long by itself. You can even see that in the film.
None of which changes the fact that the character had little chance of properly gauging and executing a useful release point. Have you ever been in an aircraft in a spin?
 

Onyx

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Thank you.

And I agree, the center of rotation, depending on how straight the arm is, will be several feet from Sandra. And in the film it looks like it is indeed at least 3-8 feet from her as the arm has lost about 1/3 of its original length. (Though we never see a static full screen shot of the spinning arm.) So she and the arm will move apart when released, which is also depicted in the film. Also depicted is Clooney saying "I can't see you. Release, release!".

What is it you think is wrong with this scene? If Clooney can't see her and she is spinning in two axes, what should he be telling her to do?
 

psikeyhackr

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What is it you think is wrong with this scene? If Clooney can't see her and she is spinning in two axes, what should he be telling her to do?
What I said was:
For me a curious thing about the movie, Gravity is the lack of discussion of when Sandra Bullock's character was supposed to release herself from the Canadarm.
They could have had her in sight of Clooney telling her to calm down and tell her when to release. Releasing at random could make matters worse But it is the lack of discussion of the rotation that I have found peculiar about this "accurate" movie.
 

Onyx

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What I said was:


They could have had her in sight of Clooney telling her to calm down and tell her when to release. Releasing at random could make matters worse But it is the lack of discussion of the rotation that I have found peculiar about this "accurate" movie.
I'm sure there would be some discussion if all the astronauts, engineers or physicists that saw it noticed something wrong with that scene. Given what is shown to be happening, I think the characters reacted realistically.
 

BAYLOR

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Lack Thereof - I still enjoy hearing made up science in old movies and early television shows.



Bad Science - People experimenting on themselves, or see someone do something stupid on Youtube, because they don't use common sense.



Hand of Death (1962)​

Good Science - Anything that can benefit humans on Earth and/or improve our world.


Hm, I do think there are issues with those three films.:D
 

BAYLOR

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I'm sure there would be some discussion if all the astronauts, engineers or physicists that saw it noticed something wrong with that scene. Given what is shown to be happening, I think the characters reacted realistically.
It did look good on the bog screen and in 3 D.:cool:
 

BAYLOR

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You're assuming that the mass is evenly distributed across the length of the arm. More likely the two ends are the heaviest parts, and the shuttle end was broken off. So if the majority of the arm's mass is left at the claw end, it is going to keep the CG near the astronaut.
Aren't all objects in Space regardless of size Weightless ?
 

psikeyhackr

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Aren't all objects in Space regardless of size Weightless ?
The Earth is in space. It is weightless. The Sun is in space. It is weightless.

I think the term "weightless" is a kind of a human scale evaluation. Since all mass creates the phenomenon of gravity every atom in any object has weight. Every atom in a wrench has weight in relation to the center of mass of the wrench.
 

BAYLOR

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Interstellar I found it Interesting that they had Advanced AI asa crew member. :)
 
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