## Saturday, December 3, 2016

### Passengers Movie Trailer Physics

I recently saw a trailer advertising the upcoming film "Passengers", starring Chris Pratt and Jennifer Lawrence. The movie is a science fiction thriller that takes place in outer space. The trailer can be seen here: https://www.youtube.com/watch?v=ATlwHzJKssQ . As shown in the trailer, a malfunction on the space shuttle causes the artificial gravity of the ship to be turned off while the character played by Jennifer Lawrence is taking a dip in the swimming pool. The result is that she is caught in a bubble that is rising upwards. I was curious about the physics behind this scene, and decided to think about it using some of the knowledge that we have learned in class this semester. Would it be possible to actually get stuck in that bubble? When the character is swimming she is able to float on the water. This is a result of both the force of gravity and the buoyancy force, we are assuming the volume of a human to be 0.069 cubic meters.

Fb= ρ fluidVfluid(g)= 1000 kg/m2*0.069m3*9.8m/s2= 1690N
Fg=mg= 62.6kg*9.8m/s2=613N

As we can see, the buoyancy force is much greater than the force of gravity, so she is pushed upwards while in the water. However, when the gravity stops, the buoyancy force becomes 0, as there is no Fg. It is therefore actually considerable that she would no longer be able to float to the top of the bubble, as shown in the trailer.

#### 1 comment:

1. There are three big physics errors in this movie :
(1) Arcturus is 36 LY from Earth. So no way to cross it after a 30 years trip travelling at half speed of light (such a trip brings you roughly at 15 light-years even taking into account relativistic corrections)

(2) When the vessel suffers an energy supply failure, we see a brutal stop of the artificial gravity. No way : The overall design of the vessel is that of a spinning wheel/cylinder. The artificial gravity in the habitable zones of the vessel is obtained by spinning-up the vessel on trip beginning. This never ends, except if you spin-down the vessel. Exactly like planet Earth : it never ends spinning except if an apocalyptic process stops it (actually there is one, but very slow, and it is not my purpose). In the movie Moonraker, a similar sequence is shown, but the scenarist shows explicitely the activation of some spin-down jets that stop the rotation of the space station wheel.

(3) Common to Passengers and Moonraker movies : when you stop artificial gravity, i.e. you abruptly spin-down the vessel, every passenger, as every free object in the cabins must keep on its inertial movement. This means everybody should fly and crash to the ceilings. This is true for sleepers in their beds, and also for Jennifer Lawrence swimming : she - and all of the water - should go and splash the ceiling of the swimming pool. Then, everything bounces and floats endlessly in the zero gravity of the space ship, this is correctly shown in both movies.