Will a gun fire in space?

[indyjoe]

Your analysis is excellent ...

You've convinced me that it would take a significant time to cool. I forgot how tiny the S-B constant was, so that offsets the temp^4. All I was thinking of was the temp^4 part.

I also did a double take on the heat capacity, then I looked again and realized you're using joules and not calories. I've been programmed to use calories for heat calculations the last three years!

You have shamed me into submission, Mr. S.

I was actually surprised it would cool that slowly as well. I went through the math twice.

 

[moischmoe]

As a fellow nerd, I would point out that "hits something or burns up on re-entry" is redundant.

I disagree. A bullet could hit something, but not burn up on re-entry. Not all objects in space have an atmosphere. The bullet could hit an asteroid, or comet, or the moon without burning up.

Also, it MIGHT not burn up when re-entering the earth's atmosphere either. The shuttle is going about 17,000 mph (25,000 fps) when it starts to hit the atmosphere. It's the shuttles forward speed that makes it get so hot, not it's vertical (falling) speed. Things burn up because they are going so fast when they hit atmosphere, not because of the fall. A fast bullet is around 5,000 fps. (Even faster in space.) If you shot a bullet in the opposite directing that the shuttle is traveling, it's speed, relative to the earth, would only be 20,000 fps. MAYBE not fast enough to burn up.

 

[rhino]

I was actually surprised it would cool that slowly as well. I went through the math twice.

Well, you also reminded me that I should have done some of the same calculations before I pontificated! Well played.

 

[indyjoe]

Yes but semi auto function may be effected

Why? All semi auto systems that I can think of would have no problems in the vacuum.

 

[Hiram2005]

I voted bacon......hope there's biscuits.