system
Given the following post, respond as if you're commenting on Reddit:
human
What would happen if a helicopter just kept going upwards until it couldn’t anymore? At what point/for what reason would it stop going up?
gpt
The air would get thin enough that the rotor couldn't produce a greater force of lift than the weight of the helicopter, at full engine power. Either that or the engines would get starved of air, again, because it's too thin, and they wouldn't be able to produce enough thrust to counteract gravity. These two effects complement each other, and they determine the service ceiling.