The Movie: Gravity

  • #26
Bandersnatch
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I was under the impression that the Hubble, the ISS and the Chinese space pod/station are hundreds of miles away from each other.
They're all within 200km orbital-height-wise, but raising or lowering the orbit takes a relatively small amount of ΔV. Changing the orbital inclination, on the other hand requires huge ΔV. The back of my envelope says that change of 28 deg inclination at velocities ~7.5km/s requires ΔV=3.6km/s.
 
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  • #27
phinds
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Even beyond the inaccuracies that BobG pointed out, the PRECISION with which a totally amateur astronaut steers to both such rendezvous is absolutely not believable ESPECIALLY considering her final method of propulsion on the second rendezvous.

I also noted that at one point she was spinning, not terribly fast, inside one of the capsules and she pulled her knees up towards her chest a bit, the way an ice skater pulls in extremities to spin faster. Rather than spinning faster, she slowed down just a little. Very poor science editing.

I'm being nit-picky here because although the special effects were generally really good, I was totally disappointed in the movie overall and wish I had saved my money. I'm sure others will disagree (certainly the critics have).
 
  • #28
Evo
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I'm being nit-picky here because although the special effects were generally really good, I was totally disappointed in the movie overall and wish I had saved my money. I'm sure others will disagree (certainly the critics have).
I think people are overlooking the content of the movie and two less than stellar actors due to being wowed by special effects, seems all of the reviews praise the effects and consider it worth watching just for the wow factor.
 
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  • #29
phinds
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I think people are overlooking the content of the movie and two less than stellar actors due to being wowed by special effects, seems all of the reviews praise the effects and consider it worth watching just for the wow factor.

Yeah, that was my take-away as well. The story-line for me broke down about half way through. I happen to like both the actors but for me they couldn't save it.
 
  • #30
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Phil Plait is absolutely crazy about the movie. :biggrin: Great review worth reading.

If you scroll down past the gushing, (based on his review, I plan to watch the movie when it's on Netflix since I know I will procrastinate until it's no longer in theaters), he does go over the science mistakes, which I think our members will be interested in.

Start at "Orbital Mechanical Breakdown"

http://www.slate.com/blogs/bad_astronomy/2013/10/04/ba_movie_review_gravity.html
 
  • #31
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Just saw Gravity in 3D and I have to say that the 3D effect looked very good to me for the first time, especially on the astronaut's helmets. Seriously. Though, this movie seemed to be mostly about the visuals and what it would be like to be in space. The plot is serviceable for the purpose of the movie, but some leaps of logic had to be made for the plot which hurt the film for me slightly. I would give the movie 3 or 4 out of 5 stars and the Haribo gummy bears I had 4 or 5 out of 5 stars. Too bad the Maryland Science Center was not showing this movie, because I am sure the astronaut's helmets would have looked even better on an IMAX screen.
 
  • #33
meBigGuy
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Sandra Bullock is wrong for the role since her face won't respond to gravitational effects.
 
  • #34
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I just saw this and it wasn't too bad, a few technical nits but that is to be expected in any movie, if a movie was 100% accurate it would be 100% more dull I think. for example in order for her to cover the distances she did in this movie she would have been traveling hundreds of miles an hour so each time she bumped into something it should have rendered her unconscious if not dead.

that being said I think the character development and portrayal in this movie were excellent. Stone's reactions were very human and very believable. I didn't see it in 3D because the ticket would have been double the price at my theater, never the less I still found the film very enjoyable and worth each of the $5 I spent.
 
  • #35
Its probably alot more theater than science though I'm betting. ALthough they claimed they have focued more on the science aspect of it.
 
  • #36
BobG
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Phil Plait is absolutely crazy about the movie. :biggrin: Great review worth reading.

If you scroll down past the gushing, (based on his review, I plan to watch the movie when it's on Netflix since I know I will procrastinate until it's no longer in theaters), he does go over the science mistakes, which I think our members will be interested in.

Start at "Orbital Mechanical Breakdown"

http://www.slate.com/blogs/bad_astronomy/2013/10/04/ba_movie_review_gravity.html

•Speaking of which, I’m not sure shrapnel hitting the robot arm would cause it to go flying and spinning off. The impact is very high speed, and I’m not sure much momentum would transfer from the debris to the arm. Hypervelocity impacts are difficult to predict, though, and I could be wrong here.

Actually, this is interesting. At hypervelocities, any overlapping portions of the two objects would shatter and travel right through each other ("ghosting"). The collision is over before the effects of the collision can travel to the ends of the objects involved. So, Plait is right to be "not sure much momentum would transfer", but some surely would, even for hypervelocity impacts.

And what percentage of momentum from a 15,000 mph collision needs to be transferred to create an incredible amount of torque on the robot arm?

I was left wondering if the robot arm was spinning too fast in the movie or if it was spinning too slow.

(Saying hypervelocity impacts are difficult to predict might be an understatement. They're actually pretty darn hard to even study. How do you get a decent sized object up to the necessary speeds and where are you going conduct your collisions? In outer space? You build computer models based on what physics you do know and run simulations, hope your model is correct, and then wait for an actual collision to occur to see if the debris pattern matched your model.)
 
  • #37
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I saw Gravity a couple years ago - something like six month after if came out, and i was very very disappointed.

I admit that my expectations where probably a bit on the high side. The movie was highly rated, i like George and Sandra... and space stuff... So what happened?

The story line has the ingredients for a poignant drama, the acting is convincing and the visuals astounding... BUT it all sounded so fake to me that it ruined it all.

--- Spoilers ahead ---

I doubt you can be so unlucky as being hit by debris from a blown out satellite that quickly - maybe after a few years in orbit? I doubt any space suit has enough "capacity" to accomplish the rescue depicted in the movie... but i may be wrong or it may be possible in not long... I can't imagine all those man made stations being so close to each other at any one time up there... I don't believe you can just "hop" from one to the other that easily... And the cherry on the cake is the final random reentry... and landing safely in a lake, just a few meter from a sand shore!

I don't mind so much when James Bond or Tony Stark do funny things because i take it as entertainment, fantasy, parody or fiction. But Gravity definitely plays the reality card and pretends to depict a potentially real situation and i just can't stand the lousy science in that case. If you can ignore that it's a movie worth seeing.
 
  • #38
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If you go into a movie made by Whollyweird you're expecting good science I hope you have your crying towel with you.
 
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  • #39
phinds
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I don't believe you can just "hop" from one to the other that easily.
As has been pointed out somewhere on this forum, the actual orbits are something like 100 miles apart vertically, making the "hop" just silly in terms of actual physics.
 
  • #40
DaveC426913
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I can't imagine all those man made stations being so close to each other at any one time up there... I don't believe you can just "hop" from one to the other that easily..
OK, it's certainly guilty of some contrivance. What film isn't? Try to find a film in whcih there isn;t a fabulous coincidence of the right thing showing up at the right time and place.

There's a reason for that. They don't make stories about the times when it didn't work out.


. And the cherry on the cake is the final random reentry... and landing safely in a lake, just a few meter from a sand shore!
Why do you think that was lucky? IIRC, some Chinese capsules were designed to touchdown on land. Instead, (more for symbolic purposes really) it fell into a lake.
 
  • #41
billy_joule
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If you go into a movie made by Whollyweird you're expecting good science I hope you have your crying towel with you.
Exactly.
To those upset with the inaccuracies, what sci-fi films are accurate?
 
  • #42
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Exactly.
To those upset with the inaccuracies, what sci-fi films are accurate?

Star wars doesn't pretend to be accurate. This movie does. That's the difference.
 
  • #43
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Star wars doesn't pretend to be accurate. This movie does. That's the difference.
You sound like a true attorney. :biggrin:
In my opinion, all movies are more or less entertaining albeit fake.
 
  • #44
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You sound like a true attorney. :biggrin:
In my opinion, all movies are more or less entertaining albeit fake.

Sure, but it's about suspending disbelief. If I watch star wars and I Yoda lifting up a space ship, that's cool. But if I see Yoda suddenly flying with light speed without a spaceship, that's not cool. On the other hand, if I suddenly see Nash lifting a spaceship in a beautiful mind, that's not cool since it doesn't fit what you deem to be possible in the movie.

Suspension of disbelief means that you're totally invested in the movie that you're "living it". If something outrageous happens you are suddenly aware again that it's just a movie, and that's not fun.

In the case of gravity, it just didn't work for me. The excuse that "it's just a movie so of course it's fake" doesn't hold up: I don't WANT to be reminded it's just a movie, I want to think it's real.
 
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  • #45
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Exactly.
To those upset with the inaccuracies, what sci-fi films are accurate?
Starship Troopers was totally accurate.

Except for the parts shown on the screen.

I mean there must have been at least one bit that was close to the book, right? Right? It just got cut because ... REASONS!
 
  • #46
Filip Larsen
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As an engineer watching Gravity I had a lot eye rolling moments where, as micromass puts it, the movie revealed that it was just a movie made to entertain people who don't really know how stuff in space works. The problem for me is that it in some sense this feeds bullshit to the viewers, that is, by constructing a sense of realism and then fail on several occasions will leave the general audience less informed about how the world actually works because they are unable to discern what is correct and what is wrong.

I understand that many of those moments I had could probably be "defended" by the general argument that if you make a space movie involving realistic aerospace systems and their operation then the audience will probably find it very boring and confusing (which is pretty much an argument against movies being overly realistic in any high-tech segment). Still, as a professional you are left with the impression that a movie like Gravity with a little effort could have fared much better. For instance, most (all?) interior scenes of rotating structures are effectively modelled as non-rotating since they are full of free-floating objects defying the basic physical laws of a rotating system. Since they were clearly able to do highly dynamic exterior shots I was disappointed they didn't do the same in the interior shot and I suspect that it leaves a fair amount of people with a reinforced impression that in space everything floats, even inside rotating structures.

Yes, I know, its just a movie, so if you are just about to press the reply button to tell me that, then there really is no need :smile:
 
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  • #47
DaveC426913
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Star wars doesn't pretend to be accurate. This movie does. That's the difference.
Star Wars also doesn't pretend to be science fiction.

Micromass' question was what science-fiction movies are accurate?
 
  • #48
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Star Wars also doesn't pretend to be science fiction.

Micromass' question was what science-fiction movies are accurate?

Star wars is space opera. Space opera is a subgenre of science fiction. It's semantics anyway and completely misses my point.
 

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