Firstly, you should see Gravity, the movie and then come read this post.
During the first sequence of the movie, while a part of me was wondering how the director was able to pull off such a long sequence without a cut, another part was wondering if a spacewalk, similar to the one that Clooney’s character was doing, orbiting the shuttle and the telescope, is possible? This another part of me, is the reason for the post.
Everything about the movie is top class. The plot is interesting, shots are beautiful, the acting is amazing, the action is edge of the seat, the 3D and sound add to the experience and don’t distract. It also pulls off a lot of things, in space, so realistically that you are left wondering how they did it. The fact that I am still thinking about it, even 5 days after seeing the movie, should be proof of how well the movie is done.
A lot of news, movie review and tech sites have already explored the inaccuracies in the science in Gravity, the movie (some good links at the end of this post). Here are a few things that came to my mind and the explanations I found.
Is a untethered space walk possible?
Yes. But an astronaut is always tethered. Zipping around the way Clooney does is not possible with the current technology.
Checkout this video on space walk facts. Noticed the tethers on the astronaut?
Does the earth look similar to how they showed in the movie from space? Especially city lights, the cyclone and the aurora?
I always thought that at the speeds that you are traveling – 7.71km/s in case of ISS – circling the earth every 90 minutes, the city lights would be a blur (read how those night city light pictures are taken here). Then, the second thing that I kept thinking was wouldn’t you see the cyclonic cloud rotating slowly from that height?
They seem to have got the detailing of these things right in general as these real time video from ISS shows. The speed with which the earth rotates is definitely wrong. Even towards the end when the Chinese pod is making an entry, the earth is shown without much rotation.
1. View of hurricane Irene:
2. View of night lights & Aurora (time lapse from 1:29 to 2:43):
However, if they had shown the earth rotating as it would, I don’t think I would have concentrated on the lead actors.
If there is a puncture in your space suit, how would you die?
Hmm… I am sure that the way it was shown in the movie – people frozen stiff – would not be true. The appearance and condition will be grave and you wouldn’t want to see it. Here is a wonderful article that looks at what happens on exposure to vacuum in more detail.
Are Hubble, ISS and Tiangong visible from each other?
This one is definitely wrong and is the first thing pointed by many articles. ISS is at a height of 230 miles (370 km), Hubble is at a height of 347 miles (559 km) and the Tiangong is at a height of 362 kilometres (225 mi). With completely different orbits, they would definitely not be in line of sight of each other. Also, since their heights are different, they would also be rotating at different speeds.
Here is a wonderful 3D tracker from NASA to to track the current positions of HST, Tiangong & ISS.
Hopping out and into different shuttles would involve complex math and not as simple and manual as they shown in the movie. And forget using a fire extinguisher to jump any distance in space.
How fast can you get in and out of a space suit?
Twice in the movie, Sandra Bullock’s character gets in and out of the movie within a minute. Not to mention that she is dressed very appropriately for coming out of the suit. The following view show and explains how it is actually done.
There are multiple blogs that state that getting in and out is a minimum of 30-45 minute affair. In reality, it would probably have taken 90 minutes for Sandra’s character to get out and again into the suit in the ISS / Capsule. Which means the debris would have done a rotation around the earth and hit it already.
This one shown in the movie is pretty wrong.
How does fire and water behave in space?
Once Sandra’s character is in the ISS, they show a blob of fire and tear floating gently away.
Fire would probably burn as a blob and not like the typical fire that they showed burn and explode in the ISS. But, I am not actually sure about this one.
These video of how a tear drop and water behaves definitely proves that the makers got the behavior of water wrong.
How plausible was the atmospheric re-entry of Tiandong as shown in the movie?
I remember an elaborate sequence in Apollo 13 that shows the precautions that the astronauts take to hit the “re-entry corridor” at the correct angle.
I didn’t actually catch the reason why the Chinese ship was descending into earth in the first place. How was the capsule programmed to be in just the right angle at re-entry?
Edit: 7th Nov’13. I am wrong on this one. There is a nice explanation on the re-entry scene at Moviestack: A very narrow re-entry angle is true only for ships returning from deep space which have high speeds . Apollo crafts returning from the Moon had to hit very slim corridors because they had enough kinetic energy to either skip off the atmosphere or burn. Coming down from low orbit means a ship has thousands of miles per hour less speed, which reduces how bad it can potentially get. You can’t skip off the atmosphere because your energy is already too small for a higher altitude orbit. It’s also very hard to come in too steep. The reason for this again is energy, but in this case it’s limited by how much energy is available in the propellant used to slow the craft, which is necessary in order to come down. When a spacecraft deorbits, it fires its motor in the direction of travel, which bends its orbital path so that it dips down into the upper atmosphere. Once there the drag force slows the ship gradually even more so that it progressively loses horizontal speed. Ultimately all that left is the vertical rate of fall due to gravity.
To summarize, some of the things that they got wrong in this movie are glaring plot holes. Any other movie with these, the science & space aficionados would have pounced on. But this film is different, it gets a lot of other things right, so geeks seem have forgiven the makers of these errors.
Here are some nice articles that explore what the movie makers got wrong.
- UCLA: How realistic is ‘Gravity’?
- Vulture: An Astronaut Fact-checks Gravity
- Blastr: Analysis based on the trailer
- Time: Gravity Fact Check: What the Season’s Big Movie Gets Wrong
- Wired: Astrophysicist Neil deGrasse Tyson Fact-Checks Gravity on Twitter
- Jalopnik: The One Really Big Error In Gravity No One Seems To Be Talking About
Post published Oct 21, Edited Oct 23.
