Non Sequitur by Wiley Miller for July 27, 2008
July 26, 2008
July 28, 2008
Transcript:
Danae: Whatcha doin', Jeffery? Jeffery: Trying to figure something out. Danae: Wanna talk about it? Jeffery: 'K... If you were on the moon, which is a vacuum, and tried to shoot a gun, would it fire? After all, combustion needs an atmosphere with oxygen... ...Or does the casing of the bullet create its own atmosphere? If so, the bullet would travel farther in the reduced gravity, but would it travel faster than it does here on Earth? Danae: Only a boy would think of bringing a gun to the moon. Jeffery: See? This is what happens every time I try to have a serious discussion with a girl!
One would presume that Wiley should know these details, in which case he is selling Jeffery substantially short in this scenario.
The whole point of propellants – in armaments and rocketry – is that they are complete, containing their own oxidiser(s). The atmosphere is in all respects an impediment, restricting the travel of the projectile and destabilising its trajectory (with the only possible exception that it may actuallylubricate the bullet as it travels down the barrel ). Other than that, the lack of atmosphere in the barrel would allow the bullet to achieve a greater exit velocity. The bullet would on all counts, travel further – I am not sure whether it could actually achieve escape velocity.
Spin stabilisation would still occur – but be less necessary or more effective as there would be negligible deviation of the projectile’s travel in the absence of atmosphere through tumbling.