In Into Darkness, there's a scene where the Enterprise enters the atmosphere of a planet,
Earth
During their descent, the crew members fall in all different directions through the ship and it seems to follow the pitch and roll of the ship in free fall. Problem is, when you're in free fall, you don't feel gravity.
Why are the crew members falling all over the place?
This was the only part of the movie that totally did not work to me. They depicted it as the gravitation of the Earth correlated with the direction in which people fall, not as a malfunction of the artificial gravity. And if it was a random on/off malfunction, this would only cause people to bounce around a little, which would look clearly different from what was shown in the scene. If they are in free fall, the microgravity would not give rise to the dramatic forces in that scene. If the friction of the Earth atmosphere was supposed to cause the fluttering and rotation of the ship, they would already be incinerated.
It seems an unlikely weakness of such an advanced vessel not to be designed in an aerodynamic fashion that avoids such dramatic fluttering. Otherwise I enjoyed the movie.
Artificial gravity was failing, but it was sporadic. It went off, came on, went of, came on - repeatedly. With many systems, when they fail, it's not simple. While (according to the TNG writer's tech manual), gravity is generated by devices under the floor that would continue for 8-10 hours without power, it seems the early model Enterprise had a different system for gravity. There's no reason to expect it to only work correctly or not at all.
We know a magnetic field around a magnet is curved. A gravitational field curves, too (otherwise ours wouldn't curve with the surface of the Earth). As the field fails, if it doesn't fail all at once, it could create flux in the field that would send crew members in one direction and ones on the other side of a gravity generator in another direction.
Also, the ship twisted and turned at times until it was in the atmosphere, which would create inertia and momentum that would throw people around.
It could perhaps be some kind of interaction with the ship's artificial gravity, which may well have been malfunctioning given the state of the Enterprise at that point.
The real answer, of course, is that the film-makers didn't think of that; or they did, and decided that the version of events as depicted would look better.
The cleanest answer, given the absurdity of the entire situation (a starship like Enterprise tumbling through the atmosphere without incinerating or coming apart?), is that Enterprise's saucer shape was intermittently acting as an air brake as she tumbled through the atmosphere. As such, the people inside would be "falling" toward a slower-moving Enterprise from time to time as she tumbled right-side up, slowed, then continued rotating to the side or front and sped back up. When Enterprise is more or less right-side-up, that's also when she's falling slowest (presenting the largest cross-section to her direction of movement), and so you'd actually get some sensation of gravity, though most likely not full gravity.
However, given this explanation, most of the scenes of people falling were inaccurate, as Enterprise would fall most slowly (and so the people inside would fall fastest) when she is falling near-parallel to her own Z-axis (that is, right-side-up or upside-down), and would fall faster (with the people inside moving more slowly relative to her) in attitudes where hallways were vertical and thus long, "dangerous" pitfalls. Most of the panicked people falling along hallways wouldn't be falling all that fast relative to Enterprise, and any impact would either be with a wall at relatively low speed, or with the floor or ceiling just a few feet away. The big thing to worry about is falling out away from a hallway or catwalk in a tall space, like Engineering or the main concourse-type area featured in a few scenes, and then falling down the "right" way as Enterprise tumbled through a level attitude.
But, out-of-universe in their defense, it takes a lot of shot planning and a lot more film fakery to make this type of thing look good. Consider Inception, specifically the hotel hallway scenes (which are stunning examples of playing with gravity in frame). For the van-tumbling scene where the hotel's pull of gravity keeps changing, they put the set on motorized rollers and turned it through 720 degrees with the camera matching the rotation. I don't know how they did the fully weightless scenes as the van dives into the water, but it's not inconceivable that they put a few of the smaller set elements on a "vomit comet" and the rest were wire rigs and digital trickery. None of this is out of the realm of possibility for any of the Star Trek shots, but most of them were of much bigger spaces, like the main concourse and cargo bay, and others, while more enclosed, were longer, and nearly every hallway in Enterprise is curved for the obvious reason. My guess is that they did quite a bit of blue-screen roller-hallway work, and larger set elements on hydraulics, but there's just no way you're going to exactly simulate the environment inside a starship tumbling through the atmosphere except, well, by being in a starship tumbling through the atmosphere. You're certainly not going to be able to get your actors to do any appreciable acting while they're busy keeping their feet.
Well, I enjoyed reading all of your theories. In short, the situation in the movie was not sufficiently explained and does go against the laws of physics and gravity. A closed object in free fall would allow all people inside to experience weightlessness. Essentially they would be floating. The principle is basically what allows NASA to train astronauts for the conditions in space without having to actually fly them there. NASA conducts weightless simulations aboard their KC-135 jumbo jet (AKA: the Vomit Comet) by plummeting to earth... Even if the on-board gravity simulation on Enterprise was failing or intermittent, the passengers would simply only fall back to the floor of the ship when it was active. They would certainly not be falling sideways through the ship as it was depicted in the 'Titanic-like ripoff' scenes. Good sci-fi movie aside from that ridiculous element.
This was addressed in considerable detail in the film's official novelisation. In short, the artificial gravity is on the fritz and the gravity generator isn't getting enough power. This causes intermittent failures on various decks as the gravity switched between local (ship's) gravity and the real gravity from the planet below.
Scott grabbed for a handhold as his feet momentarily left the floor and he started to slide up the near wall. The ship’s gravity precessers were beginning to struggle against the competing pull of the Earth’s own gravity.
“There’s not gonna be an evacuation if there’s no power to stabilize the damn ship! ” he shouted at the captain. “We lose power to the precessers and artificial gravity will be all over the place. People will be literally climbin’ the walls trying to get to their evac shuttles.”
and
Throughout the confusion, it was all the ship’s compromised computer system could do to keep the artificial gravity on the wounded Enterprise from slewing crazily from one degree to another and slamming its crew around like ball bearings in a barrel.
and
The difficulty arose from the conflict between Earth’s intensifying pull and the increasingly erratic operation of the ship’s artificial gravity system. While the crew was prepared to deal with an emergency that saw them walking on floors one minute and ceilings the next, the constant gravitational flux forced everyone to go very slowly to avoid injury. As a result, the majority of the crew had yet to make it halfway to their designated shuttles.
It is practically immpossible for the Enterprise to free fall into Earth from a distance of 230,000 km, started when they are out of warp.
The distance of the Moon to the Earth is 384,400 km and the mass is 7,349*10^22 kg, the distance of the Enterprise to the Earth is 230,000 km and the mass is 1*10^9 kg (even lower) so do your calculations, but it doesn't sum up... The Enterprise shouldn't fall into the Earth... It is totally stupid. The Enterprise shouldn't be able of taking off from an atmosphere, but that is another discussion. It is not a bad film, but this is not Star Trek (TOS) :(
At 1:18:05, after leaving warp speed and being fired upon by the big ship, you can first see the big ship closest to the Enterprise and then the moon in the middle and the earth in the background. The moon is 384,400 km from earth and they said it was 237,000 km from earth, so that is the first mistake in the scene. Also the earth would be smaller than shown in this shot.
At 1:24:51 the Enterprise is beginning to be aligned to the undamaged larger ship which should be stationary because there is no reason to suggest otherwise. At 1:39:40 is the last time you see the moon, and it is still close with the large ship in between.
At 1:40:14 the Enterprise central power grid fails, but, being so far from earth, the gravitational pull is not strong enough to pull an object that hard, especially that far from earth seeing as gravity gets stronger the closer your are. If it was, we wouldn't have any (artificial) satellites.
7 minutes later the Enterprise reaches the tops of clouds at 1:47:15. Instead of the distance from the moon, let's use the movie figure of 237,000 km from earth in 7 minutes that's 2,031,428 km/h or 1,262,270 mph. For the movie sake, let's say the ship's outer hull can withstand the temperature and other forces of stress at that speed, the ship was damaged and the inside was exposed, it should have been ripped part.
As for the crew members falling in all directions I found this to be another mistake. It started in microgravity so the effects should be minimal. It should have been the ship pushing around the crew. In microgravity the ship should have moved first and only pushed crew members after the object in motion (Enterprise) set other objects in motion (crew).
With all that off my chest I feel better, and I still would recommend this cool movie to others.
Simplest answer is normally the most likely correct. So let me try a simple explanation. They were in a ship in space above the Earth. Power failed. Based on the target audience, and maximizing dramatic effect, they chose to ignore the science of the situation altogether here and go with what the audience would be most familiar with. That is:
Ship loses artificial gravity. Earth's gravity takes over. They totally ignore microgravity at that distance from Earth. As the ship is listing and tumbling over as it descends, people are being pulled toward the Earth, as if they were on the surface of the Earth itself. That is why the direction they are falling follows a circular pattern. They are playing to the lowest common denominator in the audience, someone who doesn't understand anything about gravity at all except from personal experience.
This is totally not what would really happen, but it's what they chose to show in the film.
Of course what would really happen, being 2/3 of the way to the moon, is that they would not be experiencing such dramatic gravitational forces, but just microgravity. If artificial gravity failed they'd just start floating around and having fun. They could have been experiencing centripetal forces however. Who knows. It was a fun movie and that is all that matters.
the crew members fall in all different directions through the ship and it seems to follow the pitch and roll of the ship in free fall. Problem is, when you're in free fall, you don't feel gravity
Well, sure, but take any crewmember and the Enterprise was not rotating around that particular crewmember. So gravity or no gravity, they're going to be slamming into walls.
