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Guns in outer space or a vacuum


Finagler 6853 Life

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Here is an Alpo-esque question.  If someone was in outer space, no oxygen, no gravity, if an astronaut were to fire a gun, would it go bang?  Is there enough oxygen in the case to ignite the powder and fire the round?  The same question only using a vacuum chamber.  If you suck all the air out, would the round fire?

 

Now my head hurts.

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The cartridge would fire. Reduced drag (no atmosphere) would vastly increase the range of the bullet, and reduced or zero gravity would reduce or eliminate the deflection. 
 

Oh — and you-d probably go tumbling out of control unless you were strapped to or braced against something. 

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Heh, this reminds of a science fiction short story about two opposing countries (probably the US & USSR) with bases on the Moon.  Someone was sent to the Moon to determine how the two sides were able to co-exist peacefully.  They are sitting in the commanding officer's office discussing it when the commanding officer looks at his watch and then tells the visitor to lie on the floor.  Seconds later a hail of bullets strike the base.  The CO tells the visitor that they and the enemy had fired at each quite often when they first arrived, but found that due the lack of atmosphere and the Moon's gravity, the bullets never reached escape velocity and instead circled the Moon striking the bases at predictable times every day or so.   I wish I could remember the name of the story.

 

On edit: It was probably in 'There Will be War Vols I-IX'    a science fiction anthology series edited by Jerry Pournelle

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Lots of videos on YouTube showing guns fired under water.  Cartridge goes bang without atmospheric oxygen.

 

Not sure I want to experiment with loading in an oxygen rich environment.    The 1967 Apollo capsule fire comes to mind.

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Some of the scifi writers have tackled zero gravity shooting, as others have pointed out.   The most rational method that I've read was with the shooter moving forward like a swimmer and firing as directly ahead as possible.  After a few shots, recoil screws up his momentum and there's a tumble while the shooter keeps going in the same direction.  Many authors that I've read have limited effective shooters to specially trained troops or oddball guns like gyrojets.

 

When reading science fiction, remember the need to suspend disbelief.  The fictional universe that the author has created doesn't necessarily follow the same laws of physics as reality.  You can have a group of 400 ships the size of the moon come into a star system and enter orbit around a planet without screwing up things like solar orbits or ocean tides because the author says so.

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Phasers on kill, Mr. Sulu!  Standby the photon torpedoes! 

 

An explosion in no atmosphere would produce no sound. (See Challenger accident, although the combustion did NOT go high-order.  :-(  )    And, if you were wearing a space suit, you wouldn't hear it anyway.

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2 hours ago, Chantry said:

Heh, this reminds of a science fiction short story about two opposing countries (probably the US & USSR) with bases on the Moon

 

Love that story.   The bean counter was there to find out why they needed more high powered computers when they already had so many.   I've read it in 2 or 3 anthologies. 

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2 hours ago, Assassin said:

What if you loaded the ammo in an Oxygen rich environment? Will that increase the pressure?

 

How much oxygen do you think would be in the case? 

 

Even if loaded in a pure oxygen environment there wouldn't be enough to make any difference.   Especially since the oxidizer is built into the propellant. 

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When I was in training for the Safeguard Missile System, I asked a similar question about the Spartan missile nuclear warhead.  The Spartan was designed to intercept incoming ICBMs in the exoatmosphere (space).  During one of the tests, the test non-nuke warhead received its detonation command 3K from the target.  It was declared a direct hit!  I asked, since the nuke pops in a vacuum, what kills the target?  The instructor said, "X-ray."

 

https://en.wikipedia.org/wiki/LIM-49_Spartan

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4 hours ago, Go West said:

I can visualize the shooter going backwards from the recoil.:o

I can picture the bullet never losing any velocity not changing course until getting close enough to a huge body to be effected by gravity or an atmosphere.

 

The recoil is going to set the shooter in motion the same way but the opposite direction.

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Along those lines. what do you suppose the actual effects would be on a person floating in space if they fired a laser like in Star Wars or a phaser like in Star Trek?

 

After all there is a lot of energy in the "shot". Photons have mass as do nadion particals.

 

How would Newtons 3rd law affect the shooter?

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4 minutes ago, Sedalia Dave said:

Along those lines. what do you suppose the actual effects would be on a person floating in space if they fired a laser like in Star Wars or a phaser like in Star Trek?

 

After all there is a lot of energy in the "shot". Photons have mass as do nadion particals.

 

How would Newtons 3rd law affect the shooter?

It is the 1st, 2nd, and 3rd laws.

 

The result would match the prediction. Advanced high school physics (or basic college physics, second semester). Can be calculated and then observed with one of these:

 

Crookes_radiometer.jpg

 

A small amount of mass contains a lot of energy, so conversely a strong laser is the equivalent of a small amount of mass.

 

Black absorbs energy more than white, so shoot a laser at the black side of the flags and watch the device spin. How fast will it spin? Well, the flags have mass and the laser has a mass-equivalent energy.

 

Paraphrasing...

1st Law: The flags stay at rest until acted on by an outside force.

2nd Law: Momentum (mass X velocity) is conserved.

3rd Law: The change in momentum over time is proportional to the applied force.

 

 

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I submit that a shot fired in space would not be totally silent.

 

Simply, some of the rapidly expanding gasses would impact the shooter's helmet (or even a microphone), and would in itself cause a detectable "sound."  Not the *BOOM* of a shot fired in an atmosphere, of course, but not totally silent at arm's length.  

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55 minutes ago, Forty Rod SASS 3935 said:

I can picture the bullet never losing any velocity not changing course until getting close enough to a huge body to be effected by gravity or an atmosphere.

 

The recoil is going to set the shooter in motion the same way but the opposite direction.

But the mass of the shooter will prevent a large amount of movement.

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42 minutes ago, Sedalia Dave said:

Along those lines. what do you suppose the actual effects would be on a person floating in space if they fired a laser like in Star Wars or a phaser like in Star Trek?

 

After all there is a lot of energy in the "shot". Photons have mass as do nadion particals.

 

How would Newtons 3rd law affect the shooter?

Laser just enemy light. No effect on the laser shooter. Now a photon torpedo would be another thing.

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6 hours ago, Assassin said:

What if you loaded the ammo in an Oxygen rich environment? Will that increase the pressure?

The additional oxygen would be miniscule compared to the volume of gasses in the detonation of one cartridge worth of nitroglycerin or nitrocellulose.

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1 hour ago, Hardpan Curmudgeon SASS #8967 said:

I submit that a shot fired in space would not be totally silent.

 

Simply, some of the rapidly expanding gasses would impact the shooter's helmet (or even a microphone), and would in itself cause a detectable "sound."  Not the *BOOM* of a shot fired in an atmosphere, of course, but not totally silent at arm's length.  

I disagree. The expanding gas would be much less dense than air. I think the amount of the expanding gas from a cartridge would not be sufficient enough in volume to impact the helmet to the extent it would cause a vibration detectable by the ear.

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1 hour ago, Utah Bob #35998 said:

But the mass of the shooter will prevent a large amount of movement.

 

1 hour ago, Forty Rod SASS 3935 said:

And if the gun isn't centered he's going to have one wild ride.

 

5 minutes ago, Ace_of_Hearts said:

And if you are a really good shot, you can shoot yourself in the back.

 

 

If we picture our shooter upright, facing to the left, firearm at shoulder height, and project the standard X, Y, Z axes, with X being front to back, Y being normal to that through his hips (roughly), and Z being normal to both and through his height, when he fires he will start spinning, slowly, on his Y axis (in this case we would see it as clockwise) while at the same time being pushed in a positive direction along his X axis.   In theory.  There may be some negative motion along his Z axis.  This is assuming that the origin (meeting of all three axes) is at his center of mass.

 

 

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8 hours ago, Marshal Mo Hare, SASS #45984 said:

Explosives have everything needed for the BOOM.

 

 

 

 

Same reason that you can fire a gun under water.

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On 2/8/2021 at 10:30 AM, Smuteye John SASS#24774 said:

Some of the scifi writers have tackled zero gravity shooting, as others have pointed out.   The most rational method that I've read was with the shooter moving forward like a swimmer and firing as directly ahead as possible.  After a few shots, recoil screws up his momentum and there's a tumble while the shooter keeps going in the same direction.  Many authors that I've read have limited effective shooters to specially trained troops or oddball guns like gyrojets.

 

When reading science fiction, remember the need to suspend disbelief.  The fictional universe that the author has created doesn't necessarily follow the same laws of physics as reality.  You can have a group of 400 ships the size of the moon come into a star system and enter orbit around a planet without screwing up things like solar orbits or ocean tides because the author says so.

I worked for the manufacturer of Gyrojets, MB Associates, for about 8 months after graduation from UCB in 1968-1969.  They had a vacuum chamber where they tested chaff dispensing gyrojets.

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