# Gravity! \[open spoilers\] **URL:** \ **Category:** Cafe Society\ **Created:** [May 10, 2013, 1:41am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950 "2013-05-10T01:41:11Z")\ **Posts on this page:** 20\ **Page:** 8
**Author:** ![Cubsfan](https://avatars.discourse-cdn.com/v4/letter/c/f4b2a3/32.png) [@Cubsfan](https://boards.straightdope.com/u/Cubsfan)\ **Post date:** [October 7, 2013, 4:48pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/141 "2013-10-07T16:48:52Z")
Anyone able to answer my question about clooneys rank from up thread? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 7, 2013, 5:09pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/142 "2013-10-07T17:09:47Z")
> [@Mithras](#): > > It’s not really delta-V but the debris only works the way it does to make an exciting movie. Specifically, its new orbit must intersect the single orbit used by every other spacecraft in at most two points. It taking out a single other object would be miraculous. But it hits every useful communications satellite and threatens every manned spacecraft on successive orbits. As previously noted, this was a result of a Kessler cascading collisional syndrome; in short, an energetic impact (in this case, the destruction of a Russian spy satellite by an anti-satellite system) produces a debris field with significantly diverging impulse to intersect with other objects in orbit, which produces more debris, et cetera, until a chain reaction makes entire swaths of orbital space into a non-operational environment. This was not a concoction of the screen writers; it was proposed by Donald Kessler of NASA’s Environmental Effects Project Office at Johnson Space Center in the late 'Seventies and has subsequently been the subject of many studies, simulations, and mitigation proposals. The effects of artificially produced debris have already been experienced on the STS, the ISS, and Mir, and although not conclusively demonstrated may have been the causative element for a handful of launch and space system failures in the last twenty years. The way the debris was portrayed–large chunks moving at a few hundred meters per second–was somewhat realistic, as impacts will often occur at thousands of meters per second resulting in molten droplets and small fragments of paint, fasteners, et cetera which would literally shred an unprotected astronaut. The speed at which these cascades can occur and, in the worst case, spread, is nothing short of astronomical, and we have been more lucky than smart that we have not experienced an unconfined cascade to date. That such a cascade would take out GPS and TDRSS while also impacting the orbit of the ISS and HST almost simultaneously is a bit of a stretch, but since the orbit and initial debris field of the origin incident were never specified, it is possible that a highly elliptical and inclined orbit could produce a broad spread of both azimuth and orbital energies, initiating cascades at various circular orbits in short order. > [@Kimstu](#): > > I’m also curious to learn if there’s any reason in the plot or in the moviemaking history why Dr Ryan Stone, the Bullock character, wasn’t written as an _optical_ engineer or some other engineering subfield that would make more sense in the context of the Hubble Space Telescope. Has any real-life researcher with “biomedical” in their job title ever even been _near_ the Hubble, in orbit or otherwise? There was some brief discussion that the system she was working on was a prototype based upon some scanning or imaging equipment that she was using in her research. This is not so implausible as it may seem; many of the algorithms used in searching and filtering cosmic fields are quite similar to those used to look at protein structures, because both are looking for complex and (relative to scale) long range interactions, and adapting specific hardware to something like the HST may require very discipline-specific expertise. (I’ll note that pretty much the same premise was used to justify a bunch of geriatrics flying a Shuttle repair/salvage mission in the much more implausible _Space Cowboys_.) I think the reason for this premise plotwise was to establish that Dr. Stone was not a space geek or professional astronaut and so was not as comfortable dealing with hazards and improvising as the flight jock Kowalski. That she had at least some rudimentary training with the Soyuz capsule is not surprising; this is likely part of astronaut core training, and might especially make sense if (as portrayed in the movie) the HST and ISS were in relatively close proximity such that a rescue mission could be mounted from or to the ISS. The actual procedures for landing the Soyuz, or for that matter the Shuttle, are actually pretty simple as most of the actual maneuvers are completely automated in normal operation. It really is pretty much as simple as load a flight program for a given target point and push a sequence of buttons. The Soyuz (and presumably the Shén Zhōu) are designed to land on land or water and start screaming like Sarah Michelle Geller in a shitty horror movie. It may be a stretch that Stone figured out the controls on the totally unfamiliar Shén Zhōu (I have no idea how close it may or may not be to the Soyuz TMA) but given I figured out how to use a Japanese car GPS system despite not being able to make out any of the characters in just a few minutes, I’ll give it a pass. Realistically it would be more likely that she would die somewhere in orbit rather than surviving this leapfrog adventure from station to capsule to station, but that would not make for nearly as interesting or viscerally exciting of a film. Stranger ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 7, 2013, 5:24pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/143 "2013-10-07T17:24:46Z")
> [@Cubsfan](#): > > Anyone able to answer my question about clooneys rank from up thread? I didn’t hear a rank being stated, and I think it would be unusual to refer to a character by rank. Although many astronauts are active duty military and are seconded to NASA, they are usually referred to formally by operational role (“Commander”, “Pilot”, “Mission Specialist”) and informally by name. Remember that NASA is a civilian agency that is entirely separate from the Department of Defense, even though some of its operations support DoD programs. It is entirely possible for a lower ranking office in one service to have operational authority over a higher ranking officer from the same or another branch depending on operational role, and so the normal military chain of command is not in effect. > [@tracer](#): > > Indeed, the initial speculation that the Russians had shot a missile at one of their _spy_ satellites makes it even more suspicious. Spysats are all in Low Earth orbit – the closer to Earth they are, the more resolution their cameras can get on their subjects. There’s no way the debris from a spysat-missile collision could have enough oomph to climb all the way up to Geosynchronous orbit and start playing billiards with Comsats. This is not necessarily true. Optical satellites are likely in low but highly inclined and elliptical orbits designed to optimize dwell time over a specific area, but ELINT satellites, designed to cover a broader area may be in medium orbit or higher. Again, debris from a highly inclined or elliptical orbit may intersect a number of orbits in rapid succession. > [@tracer](#): > > EDIT: What I wanna know is, how did this random pile of debris get itself onto a **stable** 90-minute orbit (90 minutes would be a Low Earth orbit) that managed to circle the earth _three times_ before hitting the atmosphere? An intercept of, say, the ISS is going to produce a debris field with some component in a near orbit (slightly inclined with respect to the original plane of reference) with an intercept at approximately the same ascending node and at the same orbital interval. So, if the ISS were orbiting in a 90 minute orbit (it is actually at about 93 minutes) then some portion of a debris field from an original intercept would likely re-intercept at approximately the same interval, and because of the debris created by both self-intercepts and tidal forces may stretch and diverge. Stranger ---
**Author:** ![jharvey963](https://avatars.discourse-cdn.com/v4/letter/j/54ee81/32.png) [@jharvey963](https://boards.straightdope.com/u/jharvey963)\ **Post date:** [October 7, 2013, 5:36pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/144 "2013-10-07T17:36:14Z")
2 Quick comments. (Ok, 3) I loved this movie, despite its (few) science flaws. First comment. I thought the movie was very accurate on most aspects in space. One thing that struck me as inaccurate, though, was Sandra’s tears drifting off. I remember seeing a youtube video by that Canadian astronaut about wringing out a wet washrag. Even though he wrung it hard, all of the water stayed with the rag. So her tears should have stayed in her eyes. Yes, I know this the nit of nit-pickiness. 😃 Second, I first thought that the debris was in the exact same orbit as the shuttle. In that case, it wouldn’t take 90 minutes before they saw it again, but only 45 (as they passed on the other side of the earth). After a little internal fanwanking, however, I realized the orbits could have been inclined somewhat. And if there was some eccentricities, they could miss at one intersection of their orbits, and hit at the other. J. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [October 7, 2013, 8:02pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/145 "2013-10-07T20:02:07Z")
> [@Stranger\_On\_A\_Train](#): > > I think the reason for this premise plotwise was to establish that Dr. Stone was not a space geek or professional astronaut and so was not as comfortable dealing with hazards and improvising as the flight jock Kowalski. That she had at least some rudimentary training with the Soyuz capsule is not surprising; this is likely part of astronaut core training, and might especially make sense if (as portrayed in the movie) the HST and ISS were in relatively close proximity such that a rescue mission could be mounted from or to the ISS. The actual procedures for landing the Soyuz, or for that matter the Shuttle, are actually pretty simple as most of the actual maneuvers are completely automated in normal operation. […] > > It may be a stretch that Stone figured out the controls on the totally unfamiliar Shén Zhōu (I have no idea how close it may or may not be to the Soyuz TMA) but given I figured out how to use a Japanese car GPS system despite not being able to make out any of the characters in just a few minutes, I’ll give it a pass. Realistically it would be more likely that she would die somewhere in orbit rather than surviving this leapfrog adventure from station to capsule to station, but that would not make for nearly as interesting or viscerally exciting of a film. Oh, I have no problem suspending disbelief about the details of Stone’s quick learning curve and lucky survival as a rookie astronaut; as you say, that’s the sort of thing that makes a thriller exciting. But I still don’t see why a land-based optical engineer/telescope designer couldn’t be just as much a non-flight-jock Nervous Newbie In Space as a biomedical engineer, and it still seems to me that the former option would make much more sense for the movie’s premise. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [October 7, 2013, 8:26pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/146 "2013-10-07T20:26:22Z")
Dr Stone developed some sort of biomedical imaging software that ended up having applications to the Hubble telescope. It’s a plausible but largely irrelevant fact that only serves to enforce the idea that she is not a veteran member of the space program. Let’s just forget about the 90 minute debris cloud because it makes no sense. It only works if the debris is on the same exact orbit as the shuttle, ISS, and Chinese space station, but traveling in the exact opposite direction. If it were traveling in the same direction, the debris would have to be traveling at the same speed as the shuttle, etc or it would climb to a higher orbit, ever to be seen again. And in reality, each piece of debris would have it’s own orbit and would shortly be coming at our heroes randomly from every different direction. It’s just another example of a plot device to build tension. As in, 90 minutes are up, tense music starts, cue flashes of passing debris like the first drops of rain in a hurricane. ---
**Author:** ![Delayed\_Reflex](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/delayed_reflex/32/3172_2.png) [@Delayed\_Reflex](https://boards.straightdope.com/u/Delayed_Reflex)\ **Post date:** [October 7, 2013, 8:27pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/147 "2013-10-07T20:27:22Z")
> [@Kimstu](#): > > Oh, I have no problem suspending disbelief about the details of Stone’s quick learning curve and lucky survival as a rookie astronaut; as you say, that’s the sort of thing that makes a thriller exciting. > > But I still don’t see why a land-based optical engineer/telescope designer couldn’t be just as much a non-flight-jock Nervous Newbie In Space as a biomedical engineer, and it still seems to me that the former option would make much more sense for the movie’s premise. I expect it was done primarily to make Stone more sympathetic to the average audience - optical engineer/technician probably sounds terribly unsexy to the layman, while everybody loves medical doctors. Saw this on Friday and have to say it is one of the most enjoyable movies that I’ve seen in quite a while - breaktaking cinematography, incredibly thrilling sequences, and a nice length at 91 minutes. Definitely worthy of the stellar ratings that it’s received so far, IMO. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 7, 2013, 8:49pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/148 "2013-10-07T20:49:29Z")
> [@msmith537](#): > > Let’s just forget about the 90 minute debris cloud because it makes no sense. It only works if the debris is on the same exact orbit as the shuttle, ISS, and Chinese space station, but traveling in the exact opposite direction. No, this isn’t correct. In fact, if the debris field were traveling in the same orbital plane and arguments but in the opposite direction it would intercept at 45 minute intervals (again, assuming the ISS and other vehicles/stations are in a 90 minute orbital period). The reality is that the debris field formed by the initial impact is going to have some component moving in roughly the same elliptical arguments and mean anomaly at epoch but in an inclined orbit. The original body and the debris field may well reintercept at the common ascending node (relative to the Earth’s orbital plane or whatever reference plane you want to reference). Again, this is a cascading “syndrome”, so a single impact will produce a new field of debris that will spread and diverge in a range of orbital arguments and likely interact with the original field again and again, each time producing more fragments and a greater spread of the overall debris field. Although this was no doubt written in as a way to increase the tension (“Must…get…Soyuz…free…of…station…”) it is also not an unrealistic portrayal of the actual phenomenon of orbital debris. Stranger ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [October 7, 2013, 9:25pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/149 "2013-10-07T21:25:03Z")
One criticism I saw about the debris field is that it would be traveling at about ten times the speed of a bullet and so they would not have seen it coming. But I’m willing to chalk that up to dramatic license. ---
**Author:** ![Lightnin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lightnin/32/180_2.png) [@Lightnin](https://boards.straightdope.com/u/Lightnin)\ **Post date:** [October 7, 2013, 9:49pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/150 "2013-10-07T21:49:06Z")
One thing I kept thinking during the movie was, “Jesus, the Russians really fucked up the world when they shot down that satellite.” ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [October 7, 2013, 10:25pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/151 "2013-10-07T22:25:07Z")
> [@Lightnin](#): > > One thing I kept thinking during the movie was, “Jesus, the Russians really fucked up the world when they shot down that satellite.” Indeed! I look forward to seeing the political fallout of that, as well as the inevitable congressional hearings and accident investigation findings, in _Gravity 2_. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 7, 2013, 10:37pm UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/152 "2013-10-07T22:37:08Z")
> [@Lightnin](#): > > One thing I kept thinking during the movie was, “Jesus, the Russians really fucked up the world when they shot down that satellite.” That’s an understatement. A true cascading event at LEO could potentially make the entirety of the orbital altitude unavailable and could pose a major hazard to flying through into higher orbits. There is no way to protect operating spacecraft or launch vehicles against those kinds of hazards, and while there are some conceptual methods of how to clear out orbit (using aerogel “nets” or “laser brooms”, et cetera) none of these methods are realizable in the near term or even have been demonstrated to a proof of concept level. We could potentially lose satellite telecommunications, weather and climate observation, solar weather observation, and all other orbital applications indefinitely, as it would take thousands of years for material in the higher areas of LEO to degrade into a orbit where it would be subject to significant atmospheric drag and fall back to Earth. And now you know why space scientists and engineers were aghast about the 2007 Chinese ASAT test and following shootdown of USA-193 with a modified SM-3. The concerns about militarization of space aren’t just that it will lead to a new arms race or dampen commercial efforts, but that it has the potential to make orbital space literally uninhabitable by machine or person. Stranger ---
**Author:** ![SanDiegoTim](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@SanDiegoTim](https://boards.straightdope.com/u/SanDiegoTim)\ **Post date:** [October 8, 2013, 12:52am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/153 "2013-10-08T00:52:46Z")
The trailers are it. Impressive special effect in the 3D version, but no plot whatsoever. Just spent $18.00 per ticket to see it. Total waste of $36.00 and my time. ---
**Author:** ![Rollo\_Tomasi](https://avatars.discourse-cdn.com/v4/letter/r/58956e/32.png) [@Rollo\_Tomasi](https://boards.straightdope.com/u/Rollo_Tomasi)\ **Post date:** [October 8, 2013, 12:56am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/154 "2013-10-08T00:56:37Z")
Of course there’s a plot. The movie is made up of a series of events that form a narrative, which is the basic definition of a plot. It’s a rather easily described plot, actually. People need to stop falling back on “There’s no plot” when they really mean something like, “I was bored.” If that’s how you felt, that’s fine. But “no plot” is almost never accurate. ---
**Author:** ![Critical1](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@Critical1](https://boards.straightdope.com/u/Critical1)\ **Post date:** [October 8, 2013, 12:56am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/155 "2013-10-08T00:56:39Z")
> [@Dr.Strangelove](#): > > Which two delta V errors? As has been noted, the fact that the three satellites were in the same orbit was a decision by the director, not a scientific error. And the boosted maneuvering unit was well within the realm of plausibility, even if NASA doesn’t use one. I may be using delta v in the wrong tense here, coming down the flu heading towards the soyez (or whatever its called) right after the shuttle is toasted. “almost out of fuel, better wait til the last possible second and burn it all hoping its enough for us to crash dramaticaly into it instead of making tiny adjustments early and making a much gentler landing more on target and with much less drama” “gonna bail outta this thing after firing off the landing thrusters at the last possible second hoping I dont screw this up catastropically and burn all the fuel in my fire extinguisher trying to correct a really bad mistake instead of bailing out much earlier and making multiple smaller adjustments using much less fuel in the process” god damn amature hour up in this bitch ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [October 8, 2013, 1:46am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/156 "2013-10-08T01:46:46Z")
[QUOTE=Dewey Finn] One criticism I saw about the debris field is that it would be traveling at about ten times the speed of a bullet and so they would not have seen it coming. But I’m willing to chalk that up to dramatic license. [/quote] Possibly. But if it’s going in the same general direction, the debris might only be traveling a couple hundred or a thousand mph relative to the Explorer (which is also traveling 20,000 mph). Still fast enough to hit it like a missile but slow enough to see with the naked IMAX camera. ---
**Author:** ![alphaboi867](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alphaboi867/32/3898_2.png) [@alphaboi867](https://boards.straightdope.com/u/alphaboi867)\ **Post date:** [October 8, 2013, 2:19am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/157 "2013-10-08T02:19:51Z")
I saw it over the weekend in IMAX 3D with my mother. I liked and don’t really have anything to add. Mom liked it too; though she was confused by none of the spacecraft having locks (she also put the 3D glasses in her purse at the end). :smack: ---
**Author:** ![DummyGladHands](https://avatars.discourse-cdn.com/v4/letter/d/49beb7/32.png) [@DummyGladHands](https://boards.straightdope.com/u/DummyGladHands)\ **Post date:** [October 8, 2013, 2:38am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/158 "2013-10-08T02:38:07Z")
I prefer more movie with my action. And as the boyfriend is 6’8’, we always sit in the row directly behind the handicapped section, where there is a lot of leg room. I was ducking space debris. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [October 8, 2013, 2:55am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/159 "2013-10-08T02:55:56Z")
All it was was 91 minutes of tension, minimalist narrative and disciplined storytelling, in an adequate use of the 3D medium. Best $24 I’ve spent all year. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [October 8, 2013, 3:59am UTC](https://boards.straightdope.com/t/gravity-open-spoilers/657950/160 "2013-10-08T03:59:11Z")
> [@Rollo\_Tomasi](#): > > Of course there’s a plot. The movie is made up of a series of events that form a narrative, which is the basic definition of a plot. It’s a rather easily described plot, actually. > > People need to stop falling back on “There’s no plot” when they really mean something like, “I was bored.” If that’s how you felt, that’s fine. But “no plot” is almost never accurate. Who are you, the literality police? “It has no plot” is a perfectly reasonable and pretty much universally understood (if slightly hyperbolic) idiomatic way of saying that one found the plot of something to be too simple and linear to engage one’s interest. It is not just saying that one was bored, it is giving an explanation of that boredom, and an indication of why others (people who enjoy a complex plot) may be bored too, in terms of the actual characteristics of the work. [Previous page](https://boards.straightdope.com/t/gravity-open-spoilers/657950.md?page=7) [Next page](https://boards.straightdope.com/t/gravity-open-spoilers/657950.md?page=9)