Interstellar Movie - Conservation of Angular Momentum

AI Thread Summary
In "Interstellar," the ship generates rotation to create centrifugal force for simulated gravity, raising questions about the conservation of angular momentum. The initial angular momentum of the ship is zero, but when the engines fire, the gases expelled create an opposite angular momentum, conserving the overall angular momentum of the system. This principle mirrors how rockets increase linear momentum, where the expelled gases provide the necessary counterbalance. Additionally, rotation can be controlled using gyroscopes or flywheels, highlighting that the ship is not a closed system. Understanding these mechanics clarifies how the ship's rotation is achieved without violating conservation laws.
robbertypob
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OK, so I'm right in the middle of watching Interstellar and I've just seen the part where they have docked with the 'mothership' and they fire up their engines to get it to rotate. This is so they can generate a centrifugal force to simulate gravity.

My question is - first the ship was not rotating and they took action to make it rotate. How could this possibly be? Angular momentum started at 0 and was increased without any apparent external torque being applied.

Please could somebody help me out?
 
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robbertypob said:
How could this possibly be? Angular momentum started at 0 and was increased without any apparent external torque being applied.
Do you understand how rockets increase their linear momentum, without violating momentum conservation? Angular momentum is analogous.
 
Whole system(rocket + gases, which came out of engines) angular momentum was conserved. Gases, which came out of engines got opposite angular momentum.

Just like linear momentum is conserved when rocket accelerates - gases ,which come out of engine get opposite linear momentum,so whole system linear momentum is conserved.
robbertypob said:
My question is - first the ship was not rotating and they took action to make it rotate.
Only the ship is not closed system. Closed system is ship +Gases ,which come out of engines.
 
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Even without rockets you can control a craft's rotation using gyroscopes/flywheels.
 

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